Apache Karaf Container 4.x

1. Overview

Apache Karaf is a modern polymorphic application container.

Karaf can be used as a standalone container, supporting a wide range of applications and technologies. It also supports the "run anywhere" concept (on any machine with Java, cloud, docker images, …) using the embedded mode.

It’s a lightweight, powerful, and enterprise ready platform.

With this flexibility, Karaf is the perfect solution for microservices, systems integration, big data, and much more.

Apache Karaf is powered by OSGi (but you don’t need to know what OSGi is to use Karaf).

Apache Karaf uses either the Apache Felix or Eclipse Equinox OSGi frameworks, providing additional features on top of the framework.

Apache Karaf can be scaled from a very lightweight container to a fully featured enterprise service: it’s a very flexible and extensible container, covering all the major needs.

Here is a short list of provided features:

Hot deployment: simply drop a file in the deploy directory, Apache Karaf will detect the type of the file and try to deploy it.
Complete Console: Apache Karaf provides a complete Unix-like console where you can completely manage the container.
Dynamic Configuration: Apache Karaf provides a set of commands focused on managing its own configuration. All configuration files are centralized in the etc folder. Any change in a configuration file is noticed and reloaded.
Advanced Logging System: Apache Karaf supports all the popular logging frameworks (slf4j, log4j, etc). Whichever logging framework you use, Apache Karaf centralizes the configuration in one file.
Provisioning: Apache Karaf supports a large set of URLs where you can install your applications (Maven repository, HTTP, file, etc). It also provides the concept of "Karaf Features" which is a way to describe your application.
Management: Apache Karaf is an enterprise-ready container, providing many management indicators and operations via JMX.
Remote: Apache Karaf embeds an SSHd server allowing you to use the console remotely. The management layer is also accessible remotely.
Security: Apache Karaf provides a complete security framework (based on JAAS), and provides a RBAC (Role-Based Access Control) mechanism for console and JMX access.
Instances: multiple instances of Apache Karaf can be managed directly from a main instance (root).
OSGi frameworks: Apache Karaf is not tightly coupled to one OSGi framework. By default, Apache Karaf runs with the Apache Felix Framework, but you can easily switch to Equinox (just change one property in a configuration file).

2. Quick Start

These instructions should help you get Apache Karaf up and running in 5 to 15 minutes.

2.1. Prerequisites

Karaf requires a Java SE 8 or higher to run. Refer to http://www.oracle.com/technetwork/java/javase/ for details on how to download and install Java SE 1.8 or greater.

Open a Web browser and access the following URL: http://karaf.apache.org/download.html
Download the binary distribution that matches your system (zip for windows, tar.gz for unixes)
Extract the archive to a new folder on your hard drive; for example in c:\karaf - from now on this directory will be referenced as <KARAF_HOME>.

Note	Windows users should use 7zip or other unzip tool to support files longer than 255 characters.

2.2. Start the server

Open a command line console and change the directory to <KARAF_HOME>.

To start the server, run the following command in Windows:

bin\karaf.bat

respectively on Unix:

bin/karaf

You should see the following information on the command line console:

        __ __                  ____
       / //_/____ __________ _/ __/
      / ,<  / __ `/ ___/ __ `/ /_
     / /| |/ /_/ / /  / /_/ / __/
    /_/ |_|\__,_/_/   \__,_/_/

  Apache Karaf (4.2.0)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit '<ctrl-d>' or type 'system:shutdown' or 'logout' to shutdown Karaf.

karaf@root()>

2.3. Shell console basics

You can now run your first command. Simply type the <tab> key in the console.

karaf@root()>
karaf: do you wish to see to see all 356 possibilities (219 lines)?
karaf@root()> Display all 294 possibilities? (y or n)
...
shell:logout                        shell:more                          shell:new                           shell:printf                        shell:sleep                         shell:sort                          shell:source
shell:stack-traces-print            shell:tac                           shell:tail                          shell:threads                       shell:watch                         shell:wc                            shell:while
shutdown                            sleep                               sort                                source                              ssh                                 ssh                                 ssh-host-change
ssh-port-change                     ssh:ssh                             stack-traces-print                  start                               start-level                         status                              stop
su                                  sudo                                system                              system:framework                    system:name                         system:property                     system:shutdown
system:start-level                  system:version                      tac                                 tail                                threads                             tree-show                           uninstall
update                              user-add                            user-delete                         user-list                           version                             version-list                        wait
watch                               wc                                  while

You can then grab more specific help for a given command using the --help option for this command:

karaf@root()> bundle:list --help
DESCRIPTION
        bundle:list

        Lists all installed bundles.

SYNTAX
        bundle:list [options] [ids]

ARGUMENTS
        ids
                The list of bundle (identified by IDs or name or name/version) separated by whitespaces

OPTIONS
        -name, -n
                Show bundle name
        -u
                Shows the update locations
        -r
                Shows the bundle revisions
        --no-ellipsis

        -l
                Show the locations
        -s
                Shows the symbolic name
        --context, -c
                Use the given bundle context
                (defaults to 0)
        --help
                Display this help message
        -t
                Specifies the bundle threshold; bundles with a start-level less than this value will not get printed out.
        --no-format
                Disable table rendered output

Note that the console supports tab completion so if you start typing a command it will show all possible completions and also auto complete if there is only one completion.

2.4. Deploy a sample application

While you will learn in the Karaf user’s guide how to fully use and leverage Apache Karaf, let’s install a sample Apache Camel application for now:

Copy and paste the following commands in the console:

feature:repo-add camel
feature:install deployer camel-blueprint aries-blueprint
cat > deploy/example.xml <<END
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0">

    <camelContext xmlns="http://camel.apache.org/schema/blueprint">
        <route>
            <from uri="timer://test?fixedRate=true&amp;period=2000" />
            <setBody>
                <simple>Message at ${date:now:yyyy-MM-dd HH:mm:ss}</simple>
            </setBody>
            <to uri="log:test" />
        </route>
    </camelContext>

</blueprint>
END

The example that is installed is using Camel to start a timer every 2 seconds and output a message in the log. The previous commands downloaded the Camel features descriptor and installed the example feature.

You can display the log in the shell:

karaf@root()> log:display
...
2017-10-13 10:04:11,225 | INFO  | 7 - timer://test | test                             | 28 - org.apache.camel.camel-core - 2.20.0 | Exchange[ExchangePattern: InOnly, BodyType: String, Body: Message at 2017-10-13 10:04:11]
2017-10-13 10:04:13,225 | INFO  | 7 - timer://test | test                             | 28 - org.apache.camel.camel-core - 2.20.0 | Exchange[ExchangePattern: InOnly, BodyType: String, Body: Message at 2017-10-13 10:04:13]

2.5. Stopping and uninstalling the sample application

To stop and uninstall the demo, run the following command:

karaf@root()> bundle:stop example.xml
karaf@root()> bundle:uninstall example.xml

2.6. Stopping Karaf

To stop Karaf from the console, enter ^D in the console:

^D

Alternatively, you can also run the following command:

karaf@root()> feature:install system
karaf@root()> system:shutdown
Confirm: halt instance root (yes/no): yes
karaf@root()>

halt is also an alias for system:shutdown:

karaf@root()> halt

2.7. Cleaning the Karaf state

Normally Karaf remembers the features and bundles you installed and started. To reset Karaf into a clean state, just delete the data directory when Karaf is not running.

2.8. Summary

This document shows how simple it is to get Apache Karaf up and running and install a simple Apache Camel application.

3. Update Notes (from Karaf 3.x to 4.x versions)

This section is dedicated to users of previous Apache Karaf version.

Note	For the users upgrading from Karaf 2.x, please see the "Update Notes (from 2.x to 3.x)" in the Karaf 3.x documentation first.

Note	Karaf 4.x supports Java8.

3.1. Distributions

Apache Karaf 4.x is available as tar.gz and zip archives. The content is the same and works on either Unix or Windows platforms. The bin folder contains both sh and bat scripts.

3.2. Commands

Karaf 4 commands are close to the ones provided in Karaf 3.

The sub-shell modes are the same (in etc/org.apache.karaf.shell.cfg or using shell:completion command).

However, some minor changes have been introduced and new commands available:

Apache Karaf 4.x
feature:requirement-list
feature:requirement-add
feature:requirement-remove
feature:regions
feature:start
feature:stop
jaas:group-create
jaas:group-add
jaas:group-delete
jaas:group-list
jaas:group-role-add
jaas:group-role-delete
jaas:su
jaas:sudo
shell:edit
shell:env
shell:less
shell:stack-traces-print
shell:threads
shell:while
log:list
bundle:capabilities
bundle:diag
bundle:id
bundle:load-test
bundle:requirements
bundle:resolve
system:name

Apache Karaf 4.x

feature:requirement-list

feature:requirement-add

feature:requirement-remove

feature:regions

feature:start

feature:stop

jaas:group-create

jaas:group-add

jaas:group-delete

jaas:group-list

jaas:group-role-add

jaas:group-role-delete

jaas:su

jaas:sudo

shell:edit

shell:env

shell:less

shell:stack-traces-print

shell:threads

shell:while

log:list

bundle:capabilities

bundle:diag

bundle:id

bundle:load-test

bundle:requirements

bundle:resolve

system:name

We encourage the users to use the --help option to check the name and type of arguments and options.

In term of development, you can still use the blueprint definition as you do in Karaf 2.x & 3.x (with the corresponding annotations).

However, in Karaf 4.x, you can use DS and new annotations and avoid the usage of a blueprint XML.

The new annotations are available: @Service, @Completion, @Parsing, @Reference. It allows you to completely define the command in the command class directly.

To simplify the generation of the code and OSGi headers, Karaf 4.x provides the karaf-services-maven-plugin (in org.apache.karaf.tooling Maven groupId).

Take a look in the developer guide for the command development "new style" details.

3.3. Features repositories

Karaf 4.x provides:

mvn:org.apache.karaf.features/enterprise/4.0.x/xml/features
mvn:org.apache.karaf.features/framework/4.0.x/xml/features
mvn:org.apache.karaf.features/spring/4.0.x/xml/features
mvn:org.apache.karaf.features/standard/4.0.x/xml/features
mvn:org.apache.karaf.features/static/4.0.x/xml/features

3.4. Features resolver

Apache Karaf 4.x brings a complete new feature resolver. The purpose is to simplify the features installation and lifecycle. The new resolver now checks the feature requirements (defined directly in the features XML), and check which bundles provides the capabilities to satisfy these requirements. It allows Karaf to automatically install bundles required by features.

For "old style" feature (features XML using namespace from Karaf 2.x or 3.x), this feature is not enabled. As soon as you use a "new style" feature (with namespace 1.3.0 used by Karaf 4.x), this feature is enabled.

3.5. Namespaces

Apache Karaf 4.x brings updated version of the namespaces:

Supported features namespaces:
- karaf-features-1.0.0.xsd
- karaf-features-1.1.0.xsd
- karaf-features-1.2.0.xsd
- karaf-features-1.2.1.xsd
- karaf-features-1.3.0.xsd
Supported jaas namespaces:
- karaf-jaas-1.0.0.xsd
- karaf-jaas-1.1.0.xsd
Supported shell namespaces:
- karaf-shell-1.0.0.xsd
- karaf-shell-1.1.0.xsd

3.6. Maven plugin

A cleanup of the goals provided by {{karaf-maven-plugin}} has been done.

Now the provided goals are:

karaf:archive to create a tar.gz or zip of a Karaf distribution
karaf:assembly to create a custom Karaf distribution assembly
karaf:kar to create a kar file
karaf:verify to verify and validate Karaf features
karaf:features-add-to-repository to recursively copy features XML and content into a folder (repository)
karaf:features-export-meta-data to extract the metadata from a features XML
karaf:features-generate-descriptor to generate a features XML
karaf:commands-generate-help to generate help/documentation on the commands
karaf:run to run a Karaf container directly from Maven
karaf:client to interact with a remote Karaf instance
karaf:deploy to deploy an application to a remote Karaf instance

3.7. Update guide

We encourage users to start a fresh Apache Karaf 4.x container.

If you upgrade an existing container, lib and system folder have to be updated (just an override copy).

For the etc folder, a diff is required as some properties have changed and new configurations are available.

4. User Guide

4.1. Installation

Apache Karaf is a lightweight container, that is very easy to install and administer, on both Unix and Windows platforms.

4.1.1. Requirements

Hardware:

50 MB of free disk space for the Apache Karaf binary distribution.

Operating Systems:

Windows: Windows 8, Windows 7, Windows 2003, Windows Vista, Windows XP SP2, Windows 2000.
Unix: RedHat Enterprise Linux, Debian, SuSE/OpenSuSE, CentOS, Fedora, Ubuntu, MacOS, AIX, HP-UX, Solaris, any Unix platform that supports Java.

Environment:

Java SE 1.8 or greater (http://www.oracle.com/technetwork/java/javase/).
The JAVA_HOME environment variable must be set to the directory where the Java runtime is installed,

4.1.2. Using Apache Karaf binary distributions

Apache Karaf is available in two distributions, both as a tar.gz and zip archives.

The "default" distribution is a "ready to use" distribution, with pre-installed features.

The "minimal" distribution is like the minimal distributions that you can find for most of the Unix distributions. Only the core layer is packaged, most of the features and bundles are downloaded from Internet at bootstrap. It means that Apache Karaf minimal distribution requires an Internet connection to start correctly. The features provided by the "minimal" distribution are exactly the same as in the "default" distribution, the difference is that the minimal distribution will download the features from Internet.

Installation on Windows platform

Note	The JAVA_HOME environment variable has to be correctly defined. To accomplish that, press Windows key and Break key together, switch to "Advanced" tab and click on "Environment Variables".

From a browser, navigate to http://karaf.apache.org/download.html.
Download Apache Karaf binary distribution in the zip format: apache-karaf-4.0.0.zip.
Extract the files from the zip file into a directory of your choice (it’s the KARAF_HOME).

Note	Remember the restrictions concerning illegal characters in Java paths, e.g. \!, % etc.

Note

In case you have to install Karaf into a very deep path or a path containing illegal characters for Java paths, e.g. \!, % etc., you may add a bat file to start -> startup that executes

subst S: "C:\your very % problematic path!\KARAF"

so your Karaf root directory is S: --- which works for sure and is short to type.

Installation on Unix platforms

Note	The JAVA_HOME environment variable has to be correctly defined. Check the current value using echo $JAVA_HOME If it’s not correct, fix it using: export JAVA_HOME=....

From a browser, navigate to http://karaf.apache.org/download.html.
Download Apache Karaf binary distribution in the tar.gz format: apache-karaf-4.0.0.tar.gz.
Extract the files from the tar.gz file into a directory of your choice (it’s the KARAF_HOME). For example:

tar zxvf apache-karaf-4.0.0.tar.gz

Note	Remember the restrictions concerning illegal characters in Java paths, e.g. \!, % etc.

Installation on Debian GNU/linux

There is an unofficial debian package of karaf:

Add the key of the unofficial debian archive containing karaf

wget -O - https://apt.bang.priv.no/apt_pub.gpg | apt-key add -

Open /etc/apt/sources.list in a text editor and add the following lines:

# Unofficial APT archive for apache karaf
deb http://apt.bang.priv.no/public stable main

Update the APT package index and install the package
```
apt-get update
apt-get install openjdk-8-jdk karaf
```

The installed karaf will run as user karaf, group karaf, listening to the usual default karaf ports, be started with systemd, with KARAF_ETC in /etc/karaf and KARAF_DATA in /var/lib/karaf/data.

Note	When/if the link:`https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=881297`[Debian Request For Package (RFP) of karaf] results in an official karaf package becoming available, the unofficial debian package will be discontinued.

4.1.3. Post-Installation steps

Thought it is not always required, it is strongly advised to set up the JAVA_HOME environment property to point to the JDK you want Apache Karaf to use before starting it. This property is used to locate the java executable and should be configured to point to the home directory of the Java SE 8 installation.

By default, all Apache Karaf files are "gathered" in one directory: KARAF_HOME.

You can define your own directory layout, by using some Karaf environment variables:

KARAF_DATA is the location of the data folder, where Karaf stores temporary files.
KARAF_ETC is the location of the etc folder, where Karaf stores configuration files.
KARAF_BASE is the Karaf base folder. By default KARAF_BASE is the same as KARAF_HOME.

4.1.4. Building from Sources

If you intend to build Apache Karaf from the sources, the requirements are a bit different:

Hardware:

500 MB of free disk space for the Apache Karaf source distributions or SVN checkout, the Maven build and the dependencies Maven downloads.

Environment:

Java SE Development Kit 1.8 or greater (http://www.oracle.com/technetwork/java/javase/).
Apache Maven 3.5.0 or greater (http://maven.apache.org/download.html).

Building on Windows platform

You can get the Apache Karaf sources from:

the sources distribution apache-karaf-4.0.0-src.zip available at http://karaf.apache.org/download.html. Extract the files in the directory of your choice.
by checking out the git repository:

git clone https://github.com/apache/karaf karaf

Use Apache Maven to build Apache Karaf:

mvn clean install

Note	You can speed up the build by bypassing the unit tests: mvn clean install -DskipTests

Now, you can find the built binary distribution in assemblies\apache-karaf\target\apache-karaf-4.0.0.zip.

Building on Unix platforms

You can get the Apache Karaf sources from:

the sources distribution apache-karaf-4.0.0-src.tar.gz available at http://karaf.apache.org/download.html. Extract the files in the directory of your choice.
by checking out the git repository:

git clone https://github.com/apache/karaf karaf

Use Apache Maven to build Apache Karaf:

mvn clean install

Note	You can speed up the build by bypassing the unit tests: mvn clean install -DskipTests

Now, you can find the built binary distribution in assemblies/apache-karaf/target/apache-karaf-4.0.0.tar.gz.

4.2. Directory structure

The directory layout of a Karaf installation is as follows:

/bin: control scripts to start, stop, login, …
/examples: contains several examples to start with Apache Karaf
/etc: configuration files
/data: working directory
- /data/cache: OSGi framework bundle cache
- /data/generated-bundles: temporary folder used by the deployers
- /data/log: log files
/deploy: hot deploy directory
/instances: directory containing [instances|instances]
/lib: contains libraries
- /lib/boot: contains the system libraries used at Karaf bootstrap
- /lib/endorsed: directory for endorsed libraries
- /lib/ext: directory for JRE extensions
/system: OSGi bundles repository, laid out as a Maven 2 repository

Note	The `data` folder contains all the working and temporary files for Karaf. If you want to restart from a clean state, you can wipe out this directory, which has the same effect as using the clean option to the Karaf start.

4.3. Start, stop, restart, connect

4.3.1. Start

Apache Karaf supports different start modes:

the "regular" mode starts Apache Karaf in the foreground, including the shell console.
the "server" mode starts Apache Karaf in the foreground, without the shell console.
the "background" mode starts Apache Karaf in the background.

You can also manage Apache Karaf as a system service (see System Service section).

Regular mode

The regular mode uses the bin/karaf Unix script (bin\karaf.bat on Windows). It’s the default start process.

It starts Apache Karaf as a foreground process, and displays the shell console.

On Unix:

bin/karaf
        __ __                  ____
       / //_/____ __________ _/ __/
      / ,<  / __ `/ ___/ __ `/ /_
     / /| |/ /_/ / /  / /_/ / __/
    /_/ |_|\__,_/_/   \__,_/_/

  Apache Karaf (4.0.0)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit '<ctrl-d>' or type 'system:shutdown' or 'logout' to shutdown Karaf.

karaf@root()>

On Windows:

bin\karaf.bat
        __ __                  ____
       / //_/____ __________ _/ __/
      / ,<  / __ `/ ___/ __ `/ /_
     / /| |/ /_/ / /  / /_/ / __/
    /_/ |_|\__,_/_/   \__,_/_/

  Apache Karaf (4.0.0)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit '<ctrl-d>' or type 'system:shutdown' or 'logout' to shutdown Karaf.

karaf@root()>

Note	Closing the console or shell window will cause Apache Karaf to terminate.

Server mode

The server mode starts Apache Karaf as a foreground process, but it doesn’t start the shell console.

To use this mode, you use the server argument to the bin/karaf Unix script (bin\karaf.bat on Windows).

On Unix:

bin/karaf server

On Windows:

bin\karaf.bat server

Note	Closing the console or shell window will cause Apache Karaf to terminate.

You can connect to the shell console using SSH or client (see the Connect section in this page).

Background mode

The background mode starts Apache Karaf as a background process.

To start in background mode, you have to use bin/start Unix script (bin\start.bat on Windows).

On Unix:

bin/start

On Windows:

bin\start.bat

You can connect to the shell console using SSH or client (see the Connect section in this page).

Clean start

Apache Karaf stores all previously applications installed and changes that you did in the data folder.

If you want to start from a clean state, you can remove the data folder.

For convenience, you can use the clean argument to the bin/karaf Unix script (bin\karaf.bat on Windows).

On Unix:

bin/karaf clean

bin/start clean

On Windows:

bin\karaf.bat clean

bin\start.bat clean

Customize variables

Apache Karaf accepts environment variables:

JAVA_MIN_MEM: minimum memory for the JVM (default is 128M).
JAVA_MAX_MEM: maximum memory for the JVM (default is 512M).
JAVA_PERM_MEM: minimum perm memory for the JVM (default is JVM default value).
JAVA_MAX_PERM_MEM: maximum perm memory for the JVM (default is JVM default value).
KARAF_HOME: the location of your Apache Karaf installation (default is found depending on where you launch the startup script).
KARAF_BASE: the location of your Apache Karaf base (default is KARAF_HOME).
KARAF_DATA: the location of your Apache Karaf data folder (default is KARAF_BASE/data).
KARAF_ETC: the location of your Apache Karaf etc folder (default is KARAF_BASE/etc).
KARAF_OPTS: extra arguments passed to the Java command line (default is null).
KARAF_DEBUG: if true, enable the debug mode (default is null). If debug mode is enabled, Karaf starts a JDWP socket on port 5005. You can plug your IDE to define breakpoints, and run step by step.

You can define these environment variables in bin/setenv Unix script (bin\setenv.bat on Windows).

For instance, to set the minimum and maximum memory size for the JVM, you can define the following values:

On Unix:

# Content of bin/setenv
export JAVA_MIN_MEM=256M
export JAVA_MAX_MEM=1024M

On Windows:

rem Content of bin\setenv.bat
set JAVA_MIN_MEM=256M
set JAVA_MAX_MEM=1024M

Connect

Even if you start Apache Karaf without the console (using server or background modes), you can connect to the console. This connection can be local or remote. It means that you can access to Karaf console remotely.

To connect to the console, you can use the bin/client Unix script (bin\client.bat on Windows).

On Unix:

bin/client
Logging in as karaf
360 [pool-2-thread-3] WARN org.apache.sshd.client.keyverifier.AcceptAllServerKeyVerifier - Server at /0.0.0.0:8101 presented unverified key:
        __ __                  ____
       / //_/____ __________ _/ __/
      / ,<  / __ `/ ___/ __ `/ /_
     / /| |/ /_/ / /  / /_/ / __/
    /_/ |_|\__,_/_/   \__,_/_/

  Apache Karaf (4.0.0)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit 'system:shutdown' to shutdown Karaf.
Hit '<ctrl-d>' or type 'logout' to disconnect shell from current session.

karaf@root()>

On Windows:

bin\client.bat
Logging in as karaf
360 [pool-2-thread-3] WARN org.apache.sshd.client.keyverifier.AcceptAllServerKeyVerifier - Server at /0.0.0.0:8101 presented unverified key:
        __ __                  ____
       / //_/____ __________ _/ __/
      / ,<  / __ `/ ___/ __ `/ /_
     / /| |/ /_/ / /  / /_/ / __/
    /_/ |_|\__,_/_/   \__,_/_/

  Apache Karaf (4.0.0-SNAPSHOT)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit 'system:shutdown' to shutdown Karaf.
Hit '<ctrl-d>' or type 'logout' to disconnect shell from current session.

karaf@root()>

By default, client tries to connect on localhost, on port 8101 (the default Apache Karaf SSH port).

client accepts different options to let you connect on a remote Apache Karaf instance. You can use --help to get details about the options:

On Unix:

bin/client --help
Apache Karaf client
  -a [port]     specify the port to connect to
  -h [host]     specify the host to connect to
  -u [user]     specify the user name
  --help        shows this help message
  -v            raise verbosity
  -r [attempts] retry connection establishment (up to attempts times)
  -d [delay]    intra-retry delay (defaults to 2 seconds)
  -b            batch mode, specify multiple commands via standard input
  -f [file]     read commands from the specified file
  [commands]    commands to run
If no commands are specified, the client will be put in an interactive mode

On Windows:

bin\client.bat --help
Apache Karaf client
  -a [port]     specify the port to connect to
  -h [host]     specify the host to connect to
  -u [user]     specify the user name
  --help        shows this help message
  -v            raise verbosity
  -r [attempts] retry connection establishment (up to attempts times)
  -d [delay]    intra-retry delay (defaults to 2 seconds)
  -b            batch mode, specify multiple commands via standard input
  -f [file]     read commands from the specified file
  [commands]    commands to run
If no commands are specified, the client will be put in an interactive mode

Actually, client is a SSH client. You can use any SSH client to connect, like OpenSSH (ssh command) on Unix, or Putty on Windows.

For instance, on Unix, you can do:

ssh karaf@localhost -p 8101
Authenticated with partial success.
Authenticated with partial success.
Authenticated with partial success.
Password authentication
Password:
        __ __                  ____
       / //_/____ __________ _/ __/
      / ,<  / __ `/ ___/ __ `/ /_
     / /| |/ /_/ / /  / /_/ / __/
    /_/ |_|\__,_/_/   \__,_/_/

  Apache Karaf (4.0.0-SNAPSHOT)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit 'system:shutdown' to shutdown Karaf.
Hit '<ctrl-d>' or type 'logout' to disconnect shell from current session.

karaf@root()>

4.3.2. Stop

When you start Apache Karaf in regular mode, the logout command or CTRL-D key binding logs out from the console and shuts Apache Karaf down.

When you start Apache Karaf in background mode (with the bin/start Unix script (bin\start.bat on Windows)), you can use the bin/stop Unix script (bin\stop.bat on Windows).

More generally, you can use the shutdown command (on the Apache Karaf console) that works for all cases.

The shutdown command is very similar to the the shutdown Unix command.

To shutdown Apache Karaf now, you can simply use shutdown:

karaf@root()> shutdown -h
Confirm: halt instance root (yes/no):

The shutdown command asks for a confirmation. If you want to bypass the confirmation step, you can use the -f (--force) option:

karaf@root()> shutdown -f

You can also use directly halt which is an alias to shutdown -f -h.

The shutdown command accepts a time argument. With this argument, you can define when you want to shutdown the Apache Karaf container.

The time argument can have different formats. First, it can be an absolute time in the format hh:mm, in which hh is the hour (1 or 2 digits) and mm is the minute of the hour (in two digits). Second, it can be in the format m (or +m), in which m is the number of minutes to wait. The word now is an alias for 0.

For instance, the following command will shutdown Apache Karaf at 10:35am:

karaf@root()> system:shutdown 10:35

Another example to shutdown Apache Karaf in 10 minutes:

karaf@root()> system:shutdown 10

Like for other commands, you can find details on the shutdown command man page:

karaf@root()> shutdown --help
DESCRIPTION
        system:shutdown

        Shutdown Karaf.

SYNTAX
        system:shutdown [options] [time]

ARGUMENTS
        time
                Shutdown after a specified delay. The time argument can have different formats. First, it can be an abolute time in the format hh:mm, in which hh is the hour (1 or 2 digits) and mm is the minute of the hour (in two digits). Second, it can be in the format +m, in which m is the number of minutes to
                wait. The word now is an alias for +0.

OPTIONS
        -c, --clean, --clean-all, -ca
                Force a clean restart by deleting the data directory
        -f, --force
                Force the shutdown without confirmation message.
        -h, --halt
                Halt the Karaf container.
        --help
                Display this help message
        -cc, --clean-cache, -cc
                Force a clean restart by deleting the cache directory
        -r, --reboot
                Reboot the Karaf container.

4.3.3. Status

When you start Apache Karaf in background mode, you may want to check the current status.

To do so, you can use the bin/status Unix script (bin\status.bat on Windows).

Note	The status script returns 0 exit code if Apache Karaf is running, 1 exit code else.

On Unix:

bin/status
Not Running ...

bin/status
Running ...

On Windows:

bin\status.bat
Not Running ...

bin\status.bat
Running ...

4.3.4. Restart

The shutdown command accepts the -r (--restart) option to restart Apache Karaf:

karaf@root()> system:shutdown -r

Note	This command does not start a new JVM. It simply restarts the OSGi framework.

4.3.5. SystemMBean

Apache Karaf provides the JMX SystemMBean dedicated to control of the container itself.

The SystemMBean object name is org.apache.karaf:type=system.

The SystemMBean provides different attributes and operations, especially operations to halt or reboot the container:

reboot() reboots Apache Karaf now (without cleaning the cache)
reboot(time) reboots Apache Karaf at a given time (without cleaning the cache). The time format is the same as the time argument of the shutdown command.
rebootCleanCache(time) reboots Apache Karaf at a given time, including the cleanup of the cache.
rebootCleanAll(time) reboots Apache Karaf at a given time, including the cleanup of the whole data folder.
halt() shutdown Apache Karaf now.
halt(time) shutdown Apache Karaf at a given time. The time format is the same as the time argument of the shutdown command.

4.4. Integration in the operating system

In the previous chapter, we saw the different scripts and commands to start, stop, restart Apache Karaf.

Instead of using these commands and scripts, you can integrate Apache Karaf directly in your operating system service control using:

Service Wrapper
Service Script Templates

The above methods allow you to directly integrate Apache Karaf:

like a native Windows Service
like a Unix daemon process

4.4.1. Service Wrapper

The "Service Wrapper" correctly handles "user log outs" under Windows, service dependencies, and the ability to run services which interact with the desktop.

It also includes advanced fault detection software which monitors an application. The "Service Wrapper" is able to detect crashes, freezes, out of memory and other exception events, then automatically react by restarting Apache Karaf with a minimum of delay. It guarantees the maximum possible uptime of Apache Karaf.

Supported platforms

Windows 8, 7, 2008 R2, 2003, Vista (32 and 64 bits architecture)
Linux RedHat Enterprise Linux, Debian, CentOS, Fedora, Ubuntu (32 and 64 bits architecture)
FreeBSD 9.x, 8.x
AIX 5.x, 6.x, 7.x (Power architecture)
Solaris 8, 9, 10 (x86/Sparc, 32 and 64 bits architecture)
HP-UX 10.x, 11.x (32 and 64 bits architecture)
SGI Irix
MacOS X

Installation

Apache Karaf Service Wrapper is an optional feature. You have to install the "Service Wrapper" installer first.

In the console:

karaf@root()> feature:install service-wrapper

Now, you have the wrapper:install command, to "register" Apache Karaf as service/daemon on your system:

karaf@root()> wrapper:install --help
DESCRIPTION
        wrapper:install

        Install the container as a system service in the OS.

SYNTAX
        wrapper:install [options]

OPTIONS
        -d, --display
                The display name of the service.
                (defaults to karaf)
        --help
                Display this help message
        -s, --start-type
                Mode in which the service is installed. AUTO_START or DEMAND_START (Default: AUTO_START)
                (defaults to AUTO_START)
        -n, --name
                The service name that will be used when installing the service. (Default: karaf)
                (defaults to karaf)
        -D, --description
                The description of the service.
                (defaults to )

The wrapper:install command detects the running Operating Service and provides the service/daemon ready to be integrated in your system.

For instance, on a Ubuntu/Debian Linux system:

karaf@root()> wrapper:install
Creating file: /opt/apache-karaf-4.0.0/bin/karaf-wrapper
Creating file: /opt/apache-karaf-4.0.0/bin/karaf-service
Creating file: /opt/apache-karaf-4.0.0/etc/karaf-wrapper.conf
Creating missing directory: /opt/apache-karaf-4.0.0/lib/wrapper
Creating file: /opt/apache-karaf-4.0.0/lib/wrapper/libwrapper.so
Creating file: /opt/apache-karaf-4.0.0/lib/wrapper/karaf-wrapper.jar
Creating file: /opt/apache-karaf-4.0.0/lib/wrapper/karaf-wrapper-main.jar

Setup complete.  You may wish to tweak the JVM properties in the wrapper configuration file:
        /opt/apache-karaf-4.0.0/etc/karaf-wrapper.conf
before installing and starting the service.


Ubuntu/Debian Linux system detected:
  To install the service:
    $ ln -s /opt/apache-karaf-4.0.0/bin/karaf-service /etc/init.d/

  To start the service when the machine is rebooted:
    $ update-rc.d karaf-service defaults

  To disable starting the service when the machine is rebooted:
    $ update-rc.d -f karaf-service remove

  To start the service:
    $ /etc/init.d/karaf-service start

  To stop the service:
    $ /etc/init.d/karaf-service stop

  To uninstall the service :
    $ rm /etc/init.d/karaf-service

Note	You can install the wrapper without starting Karaf using bin/shell wrapper:install command.

You can note that wrapper:install command detected the running operating system ("Ubuntu/Debian Linux system detected").

You have a complete explanation and list of system commands to perform to integrate Apache Karaf in your systemV:

ln -s /opt/apache-karaf-4.0.0/bin/karaf-service /etc/init.d/
update-rc.d karaf-service defaults

Karaf also supports the systemd service, so you can use systemctl instead of a SystemV based service:

systemctl enable /opt/apache-karaf-4.0.2/bin/karaf.service

This will enable Karaf at system boot.

Uninstall

The wrapper:install provides the system commands to perform to uninstall the service/daemon.

For instance, on Ubuntu/Debian, to uninstall the Apache Karaf service, you have to remove the karaf-service script from the runlevel scripts:

rm /etc/init.d/karaf-service

If you preferred the systemd service instead of systemV:

systemctl disable karaf

You can remove the "Wrapper Service" installer after that:

karaf@root()> feature:uninstall service-wrapper

Note for MacOS users

On MacOS you can install the service for a user or for the system.

If you want to add bin/org.apache.karaf.KARAF as user service move this file into ~/Library/LaunchAgents/:

mv bin/org.apache.karaf.KARAF.plist ~/Library/LaunchAgents/

If you want to add org.apache.karaf.KARAF as system service move this into /Library/LaunchDaemons:

sudo mv bin/org.apache.karaf.KARAF.plist /Library/LaunchDaemons/

Change owner and rights:

sudo chown root:wheel /Library/LaunchDaemons/org.apache.karaf.KARAF.plist
sudo chmod u=rw,g=r,o=r /Library/LaunchDaemons/org.apache.karaf.KARAF.plist

You can test your service:

launchctl load ~/Library/LaunchAgents/org.apache.karaf.KARAF.plist
launchctl start org.apache.karaf.KARAF
launchctl stop org.apache.karaf.KARAF

Finally, after restart your session or system you can use launchctl command to start and stop your service.

If you want to remove the service call:

launchctl remove org.apache.karaf.KARAF

Configuration

When using scripts in the Apache Karaf bin folder, you can using bin/setenv Unix script (bin\setenv.bat on Windows) as described in the [Start, stop, restart, connect|start-stop] section of the documentation.

Note	The `bin/setenv` Unix script (`bin\setenv.bat` on Windows) is not used by the Apache Karaf Service Wrapper.

To configure Apache Karaf started by the Service Wrapper, you have to tune the etc/karaf-wrapper.conf file. If you provided the name option to the wrapper:install command, the file is etc/karaf-yourname.conf.

In this file, you can configure the different environment variables used by Apache Karaf. The Service Wrapper installer automatically populates these variables for you during the installation (using wrapper:install command). For instance:

set.default.JAVA_HOME is the JAVA_HOME used to start Apache Karaf (populated during Service Wrapper installation).
set.default.KARAF_HOME is the location of your Apache Karaf installation (populated during Service Wrapper installation).
set.default.KARAF_BASE is the location of your Apache Karaf installation (populated during Service Wrapper installation).
set.default.KARAF_DATA is the location of the Apache Karaf data folder (populated during Service Wrapper installation).
set.default.KARAF_ETC is the location of the Apache Karaf etc folder (populated during Service Wrapper installation).
wrapper.java.additional is used to pass additional arguments to the Java command, indexed by the argument number. The next index to use is 11.
wrapper.java.initmemory is the initial JVM memory size (the -Xms). It’s not set by default (JVM default).
wrapper.java.maxmemory is the maximum JVM memory size (the -Xmx). It’s set to 512M by default.
wrapper.logfile is the location of the Service Wrapper log file. It’s set to %KARAF_DATA%/log/wrapper.log by default.
wrapper.logfile.loglevel is the Service Wrapper log level. It’s set to INFO by default.
wrapper.logfile.maxsize is the Service Wrapper log file maximum size (before rotation). It’s set to 10m (10MB) by default.
wrapper.logfile.maxfiles is the number of Service Wrapper log files created (and rotated). It’s set to 5 by default.
wrapper.syslog.loglevel is the integration with Unix syslog daemon. By default, it’s set to none meaning disabled.
wrapper.ntservice.name is Windows service specific and defines the Windows service name. It’s set to the name option of the wrapper:install command, or karaf by default.
wrapper.ntservice.displayname is Windows service specific and defines the Windows service display name. It’s set to the display option of the wrapper:install command, or karaf by default.
wrapper.ntservice.description is Windows service specific and defines the Windows service description. It’s set to the description option of the wrapper:install command, or empty by default.
wrapper.ntservice.starttype is Windows service specific and defines if the Windows service is started automatically with the service, or just on demand. It’s set to AUTO_START by default, and could be switched to DEMAND_START.

This is a example of the generated etc/karaf-wrapper.conf file:

# ------------------------------------------------------------------------
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ------------------------------------------------------------------------

#********************************************************************
# Wrapper Properties
#********************************************************************
set.default.JAVA_HOME=/opt/jdk/1.7.0_21
set.default.KARAF_HOME=/opt/apache-karaf-4.0.0
set.default.KARAF_BASE=/opt/apache-karaf-4.0.0
set.default.KARAF_DATA=/opt/apache-karaf-4.0.0/data
set.default.KARAF_ETC=/opt/apache-karaf-4.0.0/etc

# Java Application
wrapper.working.dir=%KARAF_BASE%
wrapper.java.command=%JAVA_HOME%/bin/java
wrapper.java.mainclass=org.apache.karaf.wrapper.internal.Main
wrapper.java.classpath.1=%KARAF_HOME%/lib/karaf-wrapper.jar
wrapper.java.classpath.2=%KARAF_HOME%/lib/karaf.jar
wrapper.java.classpath.3=%KARAF_HOME%/lib/karaf-jaas-boot.jar
wrapper.java.classpath.4=%KARAF_HOME%/lib/karaf-wrapper-main.jar
wrapper.java.classpath.5=%KARAF_HOME%/lib/karaf-org.osgi.core.jar
wrapper.java.library.path.1=%KARAF_HOME%/lib/

# Application Parameters.  Add parameters as needed starting from 1
#wrapper.app.parameter.1=

# JVM Parameters
# note that n is the parameter number starting from 1.
wrapper.java.additional.1=-Dkaraf.home=%KARAF_HOME%
wrapper.java.additional.2=-Dkaraf.base=%KARAF_BASE%
wrapper.java.additional.3=-Dkaraf.data=%KARAF_DATA%
wrapper.java.additional.4=-Dkaraf.etc=%KARAF_ETC%
wrapper.java.additional.5=-Dkaraf.startLocalConsole=false
wrapper.java.additional.6=-Dkaraf.startRemoteShell=true
wrapper.java.additional.7=-Djava.io.tmpdir=%KARAF_DATA%/tmp
# Uncomment if you need libraries on Java 8
#wrapper.java.additional.9=-Djava.endorsed.dirs=%JAVA_HOME%/jre/lib/endorsed:%JAVA_HOME%/lib/endorsed:%KARAF_HOME%/lib/endorsed
#wrapper.java.additional.10=-Djava.ext.dirs=%JAVA_HOME%/jre/lib/ext:%JAVA_HOME%/lib/ext:%KARAF_HOME%/lib/ext

# Uncomment to enable jmx
#wrapper.java.additional.n=-Dcom.sun.management.jmxremote.port=1616
#wrapper.java.additional.n=-Dcom.sun.management.jmxremote.authenticate=false
#wrapper.java.additional.n=-Dcom.sun.management.jmxremote.ssl=false

# Uncomment to enable YourKit profiling
#wrapper.java.additional.n=-Xrunyjpagent

# Uncomment to enable remote debugging
#wrapper.java.additional.n=-Xdebug -Xnoagent -Djava.compiler=NONE
#wrapper.java.additional.n=-Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=5005

# Initial Java Heap Size (in MB)
#wrapper.java.initmemory=3

# Maximum Java Heap Size (in MB)
wrapper.java.maxmemory=512


#********************************************************************
# Wrapper Logging Properties
#********************************************************************
# Format of output for the console.  (See docs for formats)
wrapper.console.format=PM

# Log Level for console output.  (See docs for log levels)
wrapper.console.loglevel=INFO

# Log file to use for wrapper output logging.
wrapper.logfile=%KARAF_DATA%/log/wrapper.log

# Format of output for the log file.  (See docs for formats)
wrapper.logfile.format=LPTM

# Log Level for log file output.  (See docs for log levels)
wrapper.logfile.loglevel=INFO

# Maximum size that the log file will be allowed to grow to before
#  the log is rolled. Size is specified in bytes.  The default value
#  of 0, disables log rolling.  May abbreviate with the 'k' (kb) or
#  'm' (mb) suffix.  For example: 10m = 10 megabytes.
wrapper.logfile.maxsize=10m

# Maximum number of rolled log files which will be allowed before old
#  files are deleted.  The default value of 0 implies no limit.
wrapper.logfile.maxfiles=5

# Log Level for sys/event log output.  (See docs for log levels)
wrapper.syslog.loglevel=NONE

#********************************************************************
# Wrapper Windows Properties
#********************************************************************
# Title to use when running as a console
wrapper.console.title=karaf

#********************************************************************
# Wrapper Windows NT/2000/XP Service Properties
#********************************************************************
# WARNING - Do not modify any of these properties when an application
#  using this configuration file has been installed as a service.
#  Please uninstall the service before modifying this section.  The
#  service can then be reinstalled.

# Name of the service
wrapper.ntservice.name=karaf

# Display name of the service
wrapper.ntservice.displayname=karaf

# Description of the service
wrapper.ntservice.description=

# Service dependencies.  Add dependencies as needed starting from 1
wrapper.ntservice.dependency.1=

# Mode in which the service is installed.  AUTO_START or DEMAND_START
wrapper.ntservice.starttype=AUTO_START

# Allow the service to interact with the desktop.
wrapper.ntservice.interactive=false

4.4.2. Service Script Templates

By using the "Service Script Templates", you can run Apache Karaf with the help of operating system specific init scripts.

Note	As opposed to the Service Wrapper, the templates targeting Unix systems do not rely on 3rd party binaries

You can find these templates under the bin/contrib directory.

Unix

The karaf-service.sh utility helps you to generate ready to use scripts by automatically identifying the operating system, the default init system and the template to use.

Note	You may still need to customize the generated files to adapt them to your environment.

The utility karaf-service.sh can be configured by defining environment variables or by passing command line options:

Command line option

Environment variable

Description

-k

KARAF_SERVICE_PATH

Karaf installation path (mandatory)

-d

KARAF_SERVICE_DATA

Karaf data path (default to ${KARAF_SERVICE_PATH}/data)

-c

KARAF_SERVICE_CONF

Karaf configuration file (default to ${KARAF_SERVICE_PATH/etc/${KARAF_SERVICE_NAME}.conf

-t

KARAF_SERVICE_ETC

Karaf etc path (default to ${KARAF_SERVICE_PATH/etc}

-p

KARAF_SERVICE_PIDFILE

Karaf pid path (default to ${KARAF_SERVICE_DATA}/${KARAF_SERVICE_NAME}.pid)

-n

KARAF_SERVICE_NAME

Karaf service name (default karaf)

-e

KARAF_ENV

Karaf environment variable (can be repeated)

-u

KARAF_SERVICE_USER

Karaf user

-g

KARAF_SERVICE_GROUP

Karaf group (default ${KARAF_SERVICE_USER)

-l

KARAF_SERVICE_LOG

Karaf console log (default to ${KARAF_SERVICE_DATA}/log/${KARAF_SERVICE_NAME}-console.log)

-f

KARAF_SERVICE_TEMPLATE

Template file to use

-x

KARAF_SERVICE_EXECUTABLE

Karaf executable name (defaul karaf

Systemd

When karaf-service.sh detects Systemd, it generates three files:

a systemd unit file to manage the root Apache Karaf container
a systemd environment file with variables used by the root Apache Karaf container
a systemd template unit file to manage Apache Karaf child containers

Example

$ ./karaf-service.sh -k /opt/karaf-4 -n karaf-4
Writing service file "/opt/karaf-4/bin/contrib/karaf-4.service"
Writing service configuration file ""/opt/karaf-4/etc/karaf-4.conf"
Writing service file "/opt/karaf-4/bin/contrib/karaf-4@.service"

$ cp /opt/karaf-4/bin/contrib/karaf-4.service /etc/systemd/system
$ cp /opt/karaf-4/bin/contrib/karaf-4@.service /etc/systemd/system

$ systemctl enable karaf-4.service

SysV

When karaf-service.sh detects a SysV system, it generates two files:

an init script to manage the root Apache Karaf container
an environment file with variables used by the root Apache Karaf container

Example

$ ./karaf-service.sh -k /opt/karaf-4 -n karaf-4
Writing service file "/opt/karaf-4/bin/contrib/karaf-4"
Writing service configuration file "/opt/karaf-4/etc/karaf-4.conf"

$ ln -s /opt/karaf-4/bin/contrib/karaf-4 /etc/init.d/
$ chkconfig karaf-4 on

Note	To enable service startup upon boot, please consult your operating system init guide

Solaris SMF

When karaf-service.sh detects a Solaris system, it generates a single file:

Example

$ ./karaf-service.sh -k /opt/karaf-4 -n karaf-4 -u lburgazz -g lburgazz
Writing service file "/opt/karaf-4/bin/contrib/karaf-4.xml"

$ svccfg validate /opt/karaf-4/bin/contrib/karaf-4.xml
$ svccfg import /opt/karaf-4/bin/contrib/karaf-4.xml

Note	The generated SMF descriptor is defined as transient so the start method is executed once

Windows

Installation of Apache Karaf as windows service is supported through winsw.

Steps:

Rename karaf-service-win.exe to the service name i.e karaf-4.exe
Rename karaf-service-win.xml to match the service name i.e. karaf-4.xml
Customize the service descriptor to fit your needs
Use the service executable to install/star/stop the service

Example

C:\opt\apache-karaf-4\bin\contrib> karaf-4.exe install
C:\opt\apache-karaf-4\bin\contrib> karaf-4.exe start

4.5. Using the console

4.5.1. Available commands

To see a list of the available commands in the console, you can use the help:

karaf@root()> help
bundle                            Enter the subshell
bundle:capabilities               Displays OSGi capabilities of a given bundles.
bundle:classes                    Displays a list of classes/resources contained in the bundle
bundle:diag                       Displays diagnostic information why a bundle is not Active
bundle:dynamic-import             Enables/disables dynamic-import for a given bundle.
bundle:find-class                 Locates a specified class in any deployed bundle
bundle:headers                    Displays OSGi headers of a given bundles.
bundle:id                         Gets the bundle ID.
...

You have the list of all commands with a short description.

You can use the tab key to get a quick list of all commands:

karaf@root()> Display all 294 possibilities? (y or n)
...

4.5.2. Subshell and completion mode

The commands have a scope and a name. For instance, the command feature:list has feature as scope, and list as name.

Karaf "groups" the commands by scope. Each scope form a subshell.

You can directly execute a command with its full qualified name (scope:name):

karaf@root()> feature:list
...

or enter in a subshell and type the command contextual to the subshell:

karaf@root()> feature
karaf@root(feature)> list

You can note that you enter in a subshell directly by typing the subshell name (here feature). You can "switch" directly from a subshell to another:

karaf@root()> feature
karaf@root(feature)> bundle
karaf@root(bundle)>

The prompt displays the current subshell between ().

The exit command goes to the parent subshell:

karaf@root()> feature
karaf@root(feature)> exit
karaf@root()>

The completion mode defines the behaviour of the tab key and the help command.

You have three different modes available:

GLOBAL
FIRST
SUBSHELL

You can define your default completion mode using the completionMode property in etc/org.apache.karaf.shell.cfg file. By default, you have:

completionMode = GLOBAL

You can also change the completion mode “on the fly” (while using the Karaf shell console) using the shell:completion command:

karaf@root()> shell:completion
GLOBAL
karaf@root()> shell:completion FIRST
karaf@root()> shell:completion
FIRST

shell:completion can inform you about the current completion mode used. You can also provide the new completion mode that you want.

GLOBAL completion mode is the default one in Karaf 4.0.0 (mostly for transition purpose).

GLOBAL mode doesn’t really use subshell: it’s the same behavior as in previous Karaf versions.

When you type the tab key, whatever in which subshell you are, the completion will display all commands and all aliases:

karaf@root()> <TAB>
karaf@root()> Display all 273 possibilities? (y or n)
...
karaf@root()> feature
karaf@root(feature)> <TAB>
karaf@root(feature)> Display all 273 possibilities? (y or n)

FIRST completion mode is an alternative to the GLOBAL completion mode.

If you type the tab key on the root level subshell, the completion will display the commands and the aliases from all subshells (as in GLOBAL mode). However, if you type the tab key when you are in a subshell, the completion will display only the commands of the current subshell:

karaf@root()> shell:completion FIRST
karaf@root()> <TAB>
karaf@root()> Display all 273 possibilities? (y or n)
...
karaf@root()> feature
karaf@root(feature)> <TAB>
karaf@root(feature)>
info install list repo-add repo-list repo-remove uninstall version-list
karaf@root(feature)> exit
karaf@root()> log
karaf@root(log)> <TAB>
karaf@root(log)>
clear display exception-display get log set tail

SUBSHELL completion mode is the real subshell mode.

If you type the tab key on the root level, the completion displays the subshell commands (to go into a subshell), and the global aliases. Once you are in a subshell, if you type the TAB key, the completion displays the commands of the current subshell:

karaf@root()> shell:completion SUBSHELL
karaf@root()> <TAB>
karaf@root()>
* bundle cl config dev feature help instance jaas kar la ld lde log log:list man package region service shell ssh system
karaf@root()> bundle
karaf@root(bundle)> <TAB>
karaf@root(bundle)>
capabilities classes diag dynamic-import find-class headers info install list refresh requirements resolve restart services start start-level stop
uninstall update watch
karaf@root(bundle)> exit
karaf@root()> camel
karaf@root(camel)> <TAB>
karaf@root(camel)>
backlog-tracer-dump backlog-tracer-info backlog-tracer-start backlog-tracer-stop context-info context-list context-start context-stop endpoint-list route-info route-list route-profile route-reset-stats
route-resume route-show route-start route-stop route-suspend

4.5.3. Unix like environment

Karaf console provides a full Unix like environment.

Help or man

We already saw the usage of the help command to display all commands available.

But you can also use the help command to get details about a command or the man command which is an alias to the help command. You can also use another form to get the command help, by using the --help option to the command.

So these commands

karaf@root()> help feature:list
karaf@root()> man feature:list
karaf@root()> feature:list --help

All produce the same help output:

DESCRIPTION
        feature:list

        Lists all existing features available from the defined repositories.

SYNTAX
        feature:list [options]

OPTIONS
        --help
                Display this help message
        -o, --ordered
                Display a list using alphabetical order
        -i, --installed
                Display a list of all installed features only
        --no-format
                Disable table rendered output

Completion

When you type the tab key, Karaf tries to complete:

subshell
commands
aliases
command arguments
command options

Alias

An alias is another name associated to a given command.

The shell:alias command creates a new alias. For instance, to create the list-installed-features alias to the actual feature:list -i command, you can do:

karaf@root()> alias "list-features-installed = { feature:list -i }"
karaf@root()> list-features-installed
Name       | Version | Required | State   | Repository     | Description
------------------------------------------------------------------------------------------------------------------------------
feature    | 4.0.0   | x        | Started | standard-4.0.0 | Features Support
shell      | 4.0.0   | x        | Started | standard-4.0.0 | Karaf Shell
deployer   | 4.0.0   | x        | Started | standard-4.0.0 | Karaf Deployer
bundle     | 4.0.0   | x        | Started | standard-4.0.0 | Provide Bundle support
config     | 4.0.0   | x        | Started | standard-4.0.0 | Provide OSGi ConfigAdmin support
diagnostic | 4.0.0   | x        | Started | standard-4.0.0 | Provide Diagnostic support
instance   | 4.0.0   | x        | Started | standard-4.0.0 | Provide Instance support
jaas       | 4.0.0   | x        | Started | standard-4.0.0 | Provide JAAS support
log        | 4.0.0   | x        | Started | standard-4.0.0 | Provide Log support
package    | 4.0.0   | x        | Started | standard-4.0.0 | Package commands and mbeans
service    | 4.0.0   | x        | Started | standard-4.0.0 | Provide Service support
system     | 4.0.0   | x        | Started | standard-4.0.0 | Provide System support
kar        | 4.0.0   | x        | Started | standard-4.0.0 | Provide KAR (KARaf archive) support
ssh        | 4.0.0   | x        | Started | standard-4.0.0 | Provide a SSHd server on Karaf
management | 4.0.0   | x        | Started | standard-4.0.0 | Provide a JMX MBeanServer and a set of MBeans in

At login, the Apache Karaf console reads the etc/shell.init.script file where you can create your aliases. It’s similar to a bashrc or profile file on Unix.

ld = { log:display $args } ;
lde = { log:exception-display $args } ;
la = { bundle:list -t 0 $args } ;
ls = { service:list $args } ;
cl = { config:list "(service.pid=$args)" } ;
halt = { system:shutdown -h -f $args } ;
help = { *:help $args | more } ;
man = { help $args } ;
log:list = { log:get ALL } ;

You can see here the aliases available by default:

ld is a short form to display log (alias to log:display command)
lde is a short form to display exceptions (alias to log:exception-display command)
la is a short form to list all bundles (alias to bundle:list -t 0 command)
ls is a short form to list all services (alias to service:list command)
cl is a short form to list all configurations (alias to config:list command)
halt is a short form to shutdown Apache Karaf (alias to system:shutdown -h -f command)
help is a short form to display help (alias to *:help command)
man is the same as help (alias to help command)
log:list displays all loggers and level (alias to log:get ALL command)

You can create your own aliases in the etc/shell.init.script file.

Key binding

Like on most Unix environments, the Karaf console supports some key bindings:

the arrows key to navigate in the commands history
CTRL-D to logout/shutdown Karaf
CTRL-R to search previously executed command
CTRL-U to remove the current line

Pipe

You can pipe the output of one command as input to another one. It’s a pipe, using the | character:

karaf@root()> feature:list |grep -i war
pax-war                       | 4.1.4                            |          | Uninstalled | org.ops4j.pax.web-4.1.4  | Provide support of a full WebContainer
pax-war-tomcat                | 4.1.4                            |          | Uninstalled | org.ops4j.pax.web-4.1.4  |
war                           | 4.0.0                            |          | Uninstalled | standard-4.0.0           | Turn Karaf as a full WebContainer
blueprint-web                 | 4.0.0                            |          | Uninstalled | standard-4.0.0           | Provides an OSGI-aware Servlet ContextListener fo

Grep, more, find, …

Karaf console provides some core commands similar to a Unix environment:

shell:alias creates an alias to an existing command
shell:cat displays the content of a file or URL
shell:clear clears the current console display
shell:completion displays or change the current completion mode
shell:date displays the current date (optionally using a format)
shell:each executes a closure on a list of arguments
shell:echo echoes and prints arguments to stdout
shell:edit calls a text editor on the current file or URL
shell:env displays or sets the value of a shell session variable
shell:exec executes a system command
shell:grep prints lines matching the given pattern
shell:head displays the first line of the input
shell:history prints the commands history
shell:if allows you to use conditions (if, then, else blocks) in script
shell:info prints various information about the current Karaf instance
shell:java executes a Java application
shell:less file pager
shell:logout disconnects shell from current session
shell:more is a file pager
shell:new creates a new Java object
shell:printf formats and prints arguments
shell:sleep sleeps for a bit then wakes up
shell:sort writes sorted concatenation of all files to stdout
shell:source executes commands contained in a script
shell:stack-traces-print prints the full stack trace in the console when the execution of a command throws an exception
shell:tac captures the STDIN and returns it as a string
shell:tail displays the last lines of the input
shell:threads prints the current thread
shell:watch periodically executes a command and refresh the output
shell:wc prints newline, words, and byte counts for each file
shell:while loop while the condition is true

You don’t have to use the fully qualified name of the command, you can directly use the command name as long as it is unique. So you can use head instead of shell:head

Again, you can find details and all options of these commands using help command or --help option.

Scripting

The Apache Karaf Console supports a complete scripting language, similar to bash or csh on Unix.

The each (shell:each) command can iterate in a list:

karaf@root()> list = [1 2 3]; each ($list) { echo $it }
1
2
3

Note	The same loop could be written with the `shell:while` command: karaf@root()> a = 0 ; while { %((a+=1) <= 3) } { echo $a } 1 2 3

You can create the list yourself (as in the previous example), or some commands can return a list too.

We can note that the console created a "session" variable with the name list that you can access with $list.

The $it variable is an implicit one corresponding to the current object (here the current iterated value from the list).

When you create a list with [], Apache Karaf console creates a Java ArrayList. It means that you can use methods available in the ArrayList objects (like get or size for instance):

karaf@root()> list = ["Hello" world]; echo ($list get 0) ($list get 1)
Hello world

We can note here that calling a method on an object is directly using (object method argument). Here ($list get 0) means $list.get(0) where $list is the ArrayList.

The class notation will display details about the object:

karaf@root()> $list class
...
ProtectionDomain     ProtectionDomain  null
 null
 <no principals>
 java.security.Permissions@6521c24e (
 ("java.security.AllPermission" "<all permissions>" "<all actions>")
)


Signers              null
SimpleName           ArrayList
TypeParameters       [E]

You can "cast" a variable to a given type.

karaf@root()> ("hello world" toCharArray)
[h, e, l, l, o,  , w, o, r, l, d]

If it fails, you will see the casting exception:

karaf@root()> ("hello world" toCharArray)[0]
Error executing command: [C cannot be cast to [Ljava.lang.Object;

You can "call" a script using the shell:source command:

karaf@root> shell:source script.txt
True!

where script.txt contains:

foo = "foo"
if { $foo equals "foo" } {
  echo "True!"
}

Note

The spaces are important when writing scripts. For instance, the following script is not correct:

if{ $foo equals "foo" } ...

and will fail with:

karaf@root> shell:source script.txt
Error executing command: Cannot coerce echo "true!"() to any of []

because a space is missing after the if statement.

As for the aliases, you can create init scripts in the etc/shell.init.script file. You can also name your script with an alias. Actually, the aliases are just scripts.

See the Scripting section of the developers guide for details.

4.5.4. Security

The Apache Karaf console supports a Role Based Access Control (RBAC) security mechanism. It means that for the user connected to the console, you can define, depending on the user’s groups and roles, the permission to execute some commands, or limit the values allowed for the arguments.

Console security is detailed in the Security section of this user guide.

4.6. Remote

Apache Karaf supports a complete remote mechanism allowing you to remotely connect to a running Apache Karaf instance. More over, you can also browse, download, and upload files remotely to a running Apache Karaf instance.

Apache Karaf embeds a complete SSHd server.

Note	For security reason, by default, `karaf` user is disabled. To allow the logon, you have to have an user. You can enable `karaf` user by uncommenting the user in `etc/users.properties`: karaf = karaf,_g_:admingroup _g_\:admingroup = group,admin,manager,viewer,systembundles,ssh

4.6.1. SSHd server

When you start Apache Karaf, it enables a remote console that can be accessed over SSH.

This remote console provides all the features of the "local" console, and gives a remote user complete control over the container and services running inside of it. As the "local" console, the remote console is secured by a RBAC mechanism (see the Security section of the user guide for details).

In addition to the remote console, Apache Karaf also provides a remote filesystem. This remote filesystem can be accessed using a SCP/SFTP client.

Configuration

The configuration of the SSHd server is stored in the etc/org.apache.karaf.shell.cfg file:

################################################################################
#
#    Licensed to the Apache Software Foundation (ASF) under one or more
#    contributor license agreements.  See the NOTICE file distributed with
#    this work for additional information regarding copyright ownership.
#    The ASF licenses this file to You under the Apache License, Version 2.0
#    (the "License"); you may not use this file except in compliance with
#    the License.  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#    limitations under the License.
#
################################################################################

#
# These properties are used to configure Karaf's ssh shell.
#

#
# Via sshPort and sshHost you define the address you can login into Karaf.
#
sshPort = 8101
sshHost = 0.0.0.0

#
# The sshIdleTimeout defines the inactivity timeout to logout the SSH session.
# The sshIdleTimeout is in milliseconds, and the default is set to 30 minutes.
#
sshIdleTimeout = 1800000

#
# sshRealm defines which JAAS domain to use for password authentication.
#
sshRealm = karaf

#
# The location of the hostKey file defines where the private key of the server
# is located. If no file is at the defined location it will be ignored.
#
hostKey = ${karaf.etc}/host.key

#
# The password required to decrypt the private key of the server stored in
# 'hostKey'. This is not required if the private key stored in 'hostKey' is
# not encrypted
#hostKeyPassword =

#
# The location of the hostKeyPub file defines where the public key of the server
# is located. If no file is at the defined location it will be ignored.
#
#hostKeyPub = ${karaf.etc}/host.key.pub

#
# sshRole defines the role required to access the console through ssh
#
# sshRole = ssh

#
# Defines if the SFTP system is enabled or not in the SSH server
#
sftpEnabled=true

#
# Self defined key size in 1024, 2048, 3072, or 4096
# If not set, this defaults to 2048.
#
# keySize = 2048

#
# Specify host key algorithm, defaults to RSA
#
# algorithm = RSA

#
# Defines the completion mode on the Karaf shell console. The possible values are:
# - GLOBAL: it's the same behavior as in previous Karaf releases. The completion displays all commands and all aliases
#           ignoring if you are in a subshell or not.
# - FIRST: the completion displays all commands and all aliases only when you are not in a subshell. When you are
#          in a subshell, the completion displays only the commands local to the subshell.
# - SUBSHELL: the completion displays only the subshells on the root level. When you are in a subshell, the completion
#             displays only the commands local to the subshell.
# This property define the default value when you use the Karaf shell console.
# You can change the completion mode directly in the shell console, using shell:completion command.
#
completionMode = GLOBAL

The etc/org.apache.karaf.shell.cfg configuration file contains different properties to configure the SSHd server:

sshPort is the port number where the SSHd server is bound (by default, it’s 8101).
sshHost is the address of the network interface where the SSHd server is bound. The default value is 0.0.0.0, meaning that the SSHd server is bound on all network interfaces. You can bind on a target interface by providing the IP address of the network interface.
hostKey is the location of the host.key file. By defaut, it uses etc/host.key. This file stores the private key of the SSHd server.
hostKeyPassword is the password required to decrypt the private key of the server stored in hostKey, if the key is stored in an encrypted form. Note that Karaf does not use this property to encrypt the private key when generating it, only for reading external keys that are already encrypted. Also note that specifying a hostKeyPassword might require installing the BouncyCastle provider to support the desired encryption algorithm.
hostKeyPub is the location of the public key of the server.
sshRole is the default role used for SSH access. See the [Security section|security] of this user guide for details.
sftpEnabled controls if the SSH server starts the SFTP system or not. When enabled, Karaf SSHd supports SFTP, meaning that you can remotely access the Karaf filesystem with any sftp client.
keySize is the key size used by the SSHd server. The possible values are 1024, 2048, 3072, or 4096. The default value is 2048.
algorithm is the host key algorithm used by the SSHd server. The possible values are DSA, EC or RSA. The default value is RSA.

The SSHd server configuration can be changed at runtime:

by editing the etc/org.apache.karaf.shell.cfg configuration file
by using the config:* commands

At runtime, when you change the SSHd server configuration, you have to restart the SSHd server to load the changes. You can do it with:

karaf@root()> bundle:restart -f org.apache.karaf.shell.ssh

The Apache Karaf SSHd server supports key/agent authentication and password authentication.

Console clients

System native clients

The Apache Karaf SSHd server is a pure SSHd server, similar to a OpenSSH daemon.

It means that you can directly use a SSH client from your system.

For instance, on Unix, you can directly use OpenSSH:

~$ ssh -p 8101 karaf@localhost
Authenticated with partial success.
Authenticated with partial success.
Authenticated with partial success.
Password authentication
Password:
        __ __                  ____
       / //_/____ __________ _/ __/
      / ,<  / __ `/ ___/ __ `/ /_
     / /| |/ /_/ / /  / /_/ / __/
    /_/ |_|\__,_/_/   \__,_/_/

  Apache Karaf (4.0.0)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit 'system:shutdown' to shutdown Karaf.
Hit '<ctrl-d>' or type 'logout' to disconnect shell from current session.

karaf@root()>

On Windows, you can use Putty, Kitty, etc.

If you don’t have a SSH client installed on your machine, you can use the Apache Karaf client.

`ssh:ssh` command

Apache Karaf itself provides a SSH client. When you are on the Apache Karaf console, you have the ssh:ssh command:

karaf@root()> ssh:ssh --help
DESCRIPTION
        ssh:ssh

        Connects to a remote SSH server

SYNTAX
        ssh:ssh [options] hostname [command]

ARGUMENTS
        hostname
                The host name to connect to via SSH
        command
                Optional command to execute

OPTIONS
        --help
                Display this help message
        -p, --port
                The port to use for SSH connection
                (defaults to 22)
        -P, --password
                The password for remote login
        -q
                Quiet Mode. Do not ask for confirmations
        -l, --username
                The user name for remote login

Thanks to the ssh:ssh command, you can connect to another running Apache Karaf instance:

karaf@root()> ssh:ssh -p 8101 karaf@192.168.134.2
Connecting to host 192.168.134.2 on port 8101
Connecting to unknown server. Add this server to known hosts ? (y/n)
Storing the server key in known_hosts.
Connected
        __ __                  ____
       / //_/____ __________ _/ __/
      / ,<  / __ `/ ___/ __ `/ /_
     / /| |/ /_/ / /  / /_/ / __/
    /_/ |_|\__,_/_/   \__,_/_/

  Apache Karaf (4.0.0)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit 'system:shutdown' to shutdown Karaf.
Hit '<ctrl-d>' or type 'logout' to disconnect shell from current session.

karaf@root()>

When you don’t provide the command argument to the ssh:ssh command, you are in the interactive mode: you have a complete remote console available, where you can type commands, etc.

You can also provide directly a command to execute using the command argument. For instance, to remotely shutdown a Apache Karaf instance:

karaf@root()> ssh:ssh -p 8101 karaf@localhost system:shutdown -f
Connecting to host localhost on port 8101
Connected

As the ssh:ssh command is a pure SSH client, it means that you can connect to a Unix OpenSSH daemon:

karaf@root()> ssh:ssh user@localhost
Connecting to host localhost on port 22
Connecting to unknown server. Add this server to known hosts ? (y/n)
Storing the server key in known_hosts.
Agent authentication failed, falling back to password authentication.
Password: Connected
Last login: Sun Sep  8 19:21:12 2013
user@server:~$

Apache Karaf client

The ssh:ssh command can only be run in a running Apache Karaf console.

For convenience, the ssh:ssh command is "wrapped" as a standalone client: the bin/client Unix script (bin\client.bat on Windows).

bin/client --help
Apache Karaf client
  -a [port]     specify the port to connect to
  -h [host]     specify the host to connect to
  -u [user]     specify the user name
  --help        shows this help message
  -v            raise verbosity
  -r [attempts] retry connection establishment (up to attempts times)
  -d [delay]    intra-retry delay (defaults to 2 seconds)
  -b            batch mode, specify multiple commands via standard input
  -f [file]     read commands from the specified file
  [commands]    commands to run
If no commands are specified, the client will be put in an interactive mode

For instance, to connect to a local Apache Karaf instance (on the default SSHd server 8101 port), you can directly use bin/client Unix script (bin\client.bat on Windows) without any argument or option:

bin/client
Logging in as karaf
343 [pool-2-thread-4] WARN org.apache.sshd.client.keyverifier.AcceptAllServerKeyVerifier - Server at /0.0.0.0:8101 presented unverified key:
        __ __                  ____
       / //_/____ __________ _/ __/
      / ,<  / __ `/ ___/ __ `/ /_
     / /| |/ /_/ / /  / /_/ / __/
    /_/ |_|\__,_/_/   \__,_/_/

  Apache Karaf (4.0.0)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit 'system:shutdown' to shutdown Karaf.
Hit '<ctrl-d>' or type 'logout' to disconnect shell from current session.

karaf@root()>

When you don’t provide the command argument to the bin/client Unix script (bin\client.bat on Windows), you are in the interactive mode: you have a complete remote console available, where you can type commands, etc.

You can also provide directly a command to execute using the command argument. For instance, to remotely shutdown a Apache Karaf instance:

bin/client "system:shutdown -f"
Logging in as karaf
330 [pool-2-thread-3] WARN org.apache.sshd.client.keyverifier.AcceptAllServerKeyVerifier - Server at /0.0.0.0:8101 presented unverified key:

As the Apache Karaf client is a pure SSH client, you can use to connect to any SSHd daemon (like Unix OpenSSH daemon):

bin/client -a 22 -h localhost -u user
Logging in as user
353 [pool-2-thread-2] WARN org.apache.sshd.client.keyverifier.AcceptAllServerKeyVerifier - Server at localhost/127.0.0.1:22 presented unverified key:
Password:
Welcome to Ubuntu 13.10 (GNU/Linux 3.11.0-13-generic x86_64)

 * Documentation:  https://help.ubuntu.com/

Last login: Tue Dec  3 18:18:31 2013 from localhost

Logout

When you are connected to a remote Apache Karaf console, you can logout using:

using CTRL-D key binding. Note that CTRL-D just logs out from the remote console in this case, it doesn’t shutdown the Apache Karaf instance (as CTRL-D does when used on a local console).
using shell:logout command (or simply logout)

Filesystem clients

Apache Karaf SSHd server also provides complete fileystem access via SSH. For security reasons, the available filesystem is limited to KARAF_BASE directory.

You can use this remote filesystem with any SCP/SFTP compliant clients.

Native SCP/SFTP clients

On Unix, you can directly use scp command to download/upload files to the Apache Karaf filesystem. For instance, to retrieve the karaf.log file remotely:

~$ scp -P 8101 karaf@localhost:/data/log/karaf.log .
Authenticated with partial success.
Authenticated with partial success.
Authenticated with partial success.
Password authentication
Password:
karaf.log

As you have access to the complete KARAF_BASE directory, you can remotely change the configuration file in the etc folder, retrieve log files, populate the system folder.

On Windows, you can use WinSCP to access the Apache Karaf filesystem.

It’s probably easier to use a SFTP complient client.

For instance, on a Unix system, you can use lftp or ncftp:

$ lftp
lftp :~> open -u karaf sftp://localhost:8101
Password:
lftp karaf@localhost:~> ls
-rw-r--r--   1 jbonofre jbonofre    27754 Oct 26 10:50 LICENSE
-rw-r--r--   1 jbonofre jbonofre     1919 Dec  3 05:34 NOTICE
-rw-r--r--   1 jbonofre jbonofre     3933 Aug 18  2012 README.md
-rw-r--r--   1 jbonofre jbonofre   101041 Dec  3 05:34 RELEASE-NOTES.md
drwxr-xr-x   1 jbonofre jbonofre     4096 Dec  3 12:51 bin
drwxr-xr-x   1 jbonofre jbonofre     4096 Dec  3 18:57 data
drwxr-xr-x   1 jbonofre jbonofre     4096 Dec  3 12:51 examples
drwxr-xr-x   1 jbonofre jbonofre     4096 Dec  3 13:02 deploy
drwxr-xr-x   1 jbonofre jbonofre     4096 Dec  3 17:59 etc
drwxr-xr-x   1 jbonofre jbonofre     4096 Dec  3 13:02 instances
drwxr-xr-x   1 jbonofre jbonofre     4096 Dec  3 13:02 lib
-rw-r--r--   1 jbonofre jbonofre        0 Dec  3 13:02 lock
drwxr-xr-x   1 jbonofre jbonofre     4096 Dec  3 12:51 system
lftp karaf@localhost:/>

You can also use a graphic client like filezilla, gftp, nautilus, etc.

On Windows, you can use filezilla, WinSCP, etc.

Apache Maven

The Apache Karaf system folder is the Karaf repository, that uses a Maven directory structure. It’s where Apache Karaf looks for the artifacts (bundles, features, kars, etc).

Using Apache Maven, you can populate the system folder using the deploy:deploy-file goal.

For instance, you want to add the Apache ServiceMix facebook4j OSGi bundle, you can do:

mvn deploy:deploy-file -Dfile=org.apache.servicemix.bundles.facebook4j-2.0.2_1.jar -DgroupId=org.apache.servicemix.bundles -DartifactId=org.apache.servicemix.bundles.facebook4j -Dversion=2.0.2_1 -Dpackaging=jar -Durl=scp://localhost:8101/system

Note	If you want to turn Apache Karaf as a simple Maven repository, you can use Apache Karaf Cave.

4.6.2. JMX MBeanServer

Apache Karaf provides a JMX MBeanServer.

This MBeanServer is available remotely, using any JMX client like jconsole.

You can find details on the [Monitoring section|monitoring] of the user guide.

4.7. Log

Apache Karaf provides a very dynamic and powerful logging system.

It supports:

the OSGi Log Service
the Apache Log4j v1 and v2 framework
the Apache Commons Logging framework
the Logback framework
the SLF4J framework
the native Java Util Logging framework

It means that applications can use any logging framework, Apache Karaf will use the central log system to manage the loggers, appenders, etc.

4.7.1. Configuration files

The initial log configuration is loaded from etc/org.ops4j.pax.logging.cfg.

This file is a standard Log4j configuration file.

You find the different Log4j elements:

loggers
appenders
layouts

You can add your own initial configuration directly in the file.

The default configuration is the following:

################################################################################
#
#    Licensed to the Apache Software Foundation (ASF) under one or more
#    contributor license agreements.  See the NOTICE file distributed with
#    this work for additional information regarding copyright ownership.
#    The ASF licenses this file to You under the Apache License, Version 2.0
#    (the "License"); you may not use this file except in compliance with
#    the License.  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#    limitations under the License.
#
################################################################################

# Root logger
log4j.rootLogger=INFO, out, osgi:*
log4j.throwableRenderer=org.apache.log4j.OsgiThrowableRenderer

# CONSOLE appender not used by default
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n

# File appender
log4j.appender.out=org.apache.log4j.RollingFileAppender
log4j.appender.out.layout=org.apache.log4j.PatternLayout
log4j.appender.out.layout.ConversionPattern=%d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
log4j.appender.out.file=${karaf.log}/karaf.log
log4j.appender.out.append=true
log4j.appender.out.maxFileSize=1MB
log4j.appender.out.maxBackupIndex=10

# Sift appender
log4j.appender.sift=org.apache.log4j.sift.MDCSiftingAppender
log4j.appender.sift.key=bundle.name
log4j.appender.sift.default=karaf
log4j.appender.sift.appender=org.apache.log4j.FileAppender
log4j.appender.sift.appender.layout=org.apache.log4j.PatternLayout
log4j.appender.sift.appender.layout.ConversionPattern=%d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %m%n
log4j.appender.sift.appender.file=${karaf.log}/$\\{bundle.name\\}.log
log4j.appender.sift.appender.append=true

The default configuration only define the ROOT logger, with INFO log level, using the out file appender. You can change the log level to any Log4j valid values (from the most to less verbose): TRACE, DEBUG, INFO, WARN, ERROR, FATAL.

The osgi:* appender is a special appender to send the log message to the OSGi Log Service.

A stdout console appender is pre-configured, but not enabled by default. This appender allows you to display log messages directly to standard output. It’s interesting if you plan to run Apache Karaf in server mode (without console).

To enable it, you have to add the stdout appender to the rootLogger:

log4j.rootLogger=INFO, out, stdout, osgi:*

The out appender is the default one. It’s a rolling file appender that maintains and rotates 10 log files of 1MB each. The log files are located in data/log/karaf.log by default.

The sift appender is not enabled by default. This appender allows you to have one log file per deployed bundle. By default, the log file name format uses the bundle symbolic name (in the data/log folder).

You can edit this file at runtime: any change will be reloaded and be effective immediately (no need to restart Apache Karaf).

Another configuration file is used by Apache Karaf: etc/org.apache.karaf.log.cfg. This files configures the Log Service used by the log commands (see later).

4.7.2. Log4j v2 support

Karaf supports log4j v2 backend.

To enable log4j v2 support you have to:

Edit etc/startup.properties to replace the line org/ops4j/pax/logging/pax-logging-service/1.8.4/pax-logging-service-1.8.4.jar=8 with org/ops4j/pax/logging/pax-logging-log4j2/1.8.4/pax-logging-log4j2-1.8.4.jar=8
Add pax-logging-log4j2 jar file in system/org/ops4j/pax/logging/pax-logging-log4j2/x.x/pax-logging-log4j2-x.x.jar where x.x is the version as defined in `etc/startup.properties
Edit etc/org.ops4j.pax.logging.cfg configuration file and add org.ops4j.pax.logging.log4j2.config.file=${karaf.etc}/log4j2.xml
Add the etc/log4j2.xml configuration file.

A default configuration in etc/log4j2.xml could be:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="INFO">
    <Appenders>
        <Console name="console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{ABSOLUTE} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n"/>
        </Console>
        <RollingFile name="out" fileName="${karaf.log}/karaf.log"
              append="true" filePattern="${karaf.log}/$${date:yyyy-MM}/fuse-%d{MM-dd-yyyy}-%i.log.gz">
           <PatternLayout>
             <Pattern>%d{ABSOLUTE} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n</Pattern>
           </PatternLayout>
           <Policies>
                <TimeBasedTriggeringPolicy />
                <SizeBasedTriggeringPolicy size="250 MB"/>
            </Policies>
        </RollingFile>
        <PaxOsgi name="paxosgi" filter="VmLogAppender"/>
    </Appenders>
    <Loggers>
        <Root level="INFO">
            <AppenderRef ref="console"/>
            <AppenderRef ref="out"/>
            <AppenderRef ref="paxosgi"/>
        </Root>
    </Loggers>
</Configuration>

4.7.3. `karaf.log.console` property

Before Karaf starts proper logging facilities (pax-logging), it may configure java.util.logging. Standard Java logging is used initially by the Main class and org.apache.karaf.main.lock.Lock implementations. In order to configure the logging level, please set the system property karaf.log.console to one of the standard JUL levels:

SEVERE (highest value)
WARNING
INFO
CONFIG
FINE
FINER
FINEST (lowest value)

Additionally, de-facto standard log4j(2) levels can be used:

TRACE
DEBUG
INFO
WARN
ERROR
OFF
DEFAULT

And because org.ops4j.pax.logging PID uses karaf.log.console property, it’s in fact better to use log4j levels instead:

log4j2.rootLogger.appenderRef.Console.filter.threshold.level = ${karaf.log.console:-OFF}

For example, setting karaf.log.console to INFO (or lower) will turn on these logs when starting Karaf:

Jul 04, 2017 7:53:18 AM org.apache.karaf.main.Main launch
INFO: Installing and starting initial bundles
Jul 04, 2017 7:53:18 AM org.apache.karaf.main.Main launch
INFO: All initial bundles installed and set to start
...

4.7.4. Commands

Instead of changing the etc/org.ops4j.pax.logging.cfg file, Apache Karaf provides a set of commands allowing to dynamically change the log configuration and see the log content:

`log:clear`

The log:clear command clears the log entries.

`log:display`

The log:display command displays the log entries.

By default, it displays the log entries of the rootLogger:

karaf@root()> log:display
2015-07-01 19:12:46,208 | INFO  | FelixStartLevel  | SecurityUtils                    | 16 - org.apache.sshd.core - 0.12.0 | BouncyCastle not registered, using the default JCE provider
2015-07-01 19:12:47,368 | INFO  | FelixStartLevel  | core                             | 68 - org.apache.aries.jmx.core - 1.1.1 | Starting JMX OSGi agent

You can also display the log entries from a specific logger, using the logger argument:

karaf@root()> log:display ssh
2015-07-01 19:12:46,208 | INFO  | FelixStartLevel  | SecurityUtils                    | 16 - org.apache.sshd.core - 0.12.0 | BouncyCastle not registered, using the default JCE provider

By default, all log entries will be displayed. It could be very long if your Apache Karaf container is running since a long time. You can limit the number of entries to display using the -n option:

karaf@root()> log:display -n 5
2015-07-01 06:53:24,143 | INFO  | JMX OSGi Agent   | core                             | 68 - org.apache.aries.jmx.core - 1.1.1 | Registering org.osgi.jmx.framework.BundleStateMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@27cc75cb with name osgi.core:type=bundleState,version=1.7,framework=org.apache.felix.framework,uuid=5335370f-9dee-449f-9b1c-cabe74432ed1
2015-07-01 06:53:24,150 | INFO  | JMX OSGi Agent   | core                             | 68 - org.apache.aries.jmx.core - 1.1.1 | Registering org.osgi.jmx.framework.PackageStateMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@27cc75cb with name osgi.core:type=packageState,version=1.5,framework=org.apache.felix.framework,uuid=5335370f-9dee-449f-9b1c-cabe74432ed1
2015-07-01 06:53:24,150 | INFO  | JMX OSGi Agent   | core                             | 68 - org.apache.aries.jmx.core - 1.1.1 | Registering org.osgi.jmx.framework.ServiceStateMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@27cc75cb with name osgi.core:type=serviceState,version=1.7,framework=org.apache.felix.framework,uuid=5335370f-9dee-449f-9b1c-cabe74432ed1
2015-07-01 06:53:24,152 | INFO  | JMX OSGi Agent   | core                             | 68 - org.apache.aries.jmx.core - 1.1.1 | Registering org.osgi.jmx.framework.wiring.BundleWiringStateMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@27cc75cb with name osgi.core:type=wiringState,version=1.1,framework=org.apache.felix.framework,uuid=5335370f-9dee-449f-9b1c-cabe74432ed1
2015-07-01 06:53:24,501 | INFO  | FelixStartLevel  | RegionsPersistenceImpl           | 78 - org.apache.karaf.region.persist - 4.0.0 | Loading region digraph persistence

You can also limit the number of entries stored and retained using the size property in the etc/org.apache.karaf.log.cfg file:

#
# The number of log statements to be displayed using log:display. It also defines the number
# of lines searched for exceptions using log:display exception. You can override this value
# at runtime using -n in log:display.
#
size = 500

By default, each log level is displayed with a different color: ERROR/FATAL are in red, DEBUG in purple, INFO in cyan, etc. You can disable the coloring using the --no-color option.

The log entries format pattern doesn’t use the conversion pattern defined in etc/org.ops4j.pax.logging.cfg file. By default, it uses the pattern property defined in etc/org.apache.karaf.log.cfg.

#
# The pattern used to format the log statement when using log:display. This pattern is according
# to the log4j layout. You can override this parameter at runtime using log:display with -p.
#
pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n

You can also change the pattern dynamically (for one execution) using the -p option:

karaf@root()> log:display -p "%d - %c - %m%n"
2015-07-01 07:01:58,007 - org.apache.sshd.common.util.SecurityUtils - BouncyCastle not registered, using the default JCE provider
2015-07-01 07:01:58,725 - org.apache.aries.jmx.core - Starting JMX OSGi agent
2015-07-01 07:01:58,744 - org.apache.aries.jmx.core - Registering MBean with ObjectName [osgi.compendium:service=cm,version=1.3,framework=org.apache.felix.framework,uuid=6361fc65-8df4-4886-b0a6-479df2d61c83] for service with service.id [13]
2015-07-01 07:01:58,747 - org.apache.aries.jmx.core - Registering org.osgi.jmx.service.cm.ConfigurationAdminMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@27cc75cb with name osgi.compendium:service=cm,version=1.3,framework=org.apache.felix.framework,uuid=6361fc65-8df4-4886-b0a6-479df2d61c83

The pattern is a regular Log4j pattern where you can use keywords like %d for the date, %c for the class, %m for the log message, etc.

`log:exception-display`

The log:exception-display command displays the last occurred exception.

As for log:display command, the log:exception-display command uses the rootLogger by default, but you can specify a logger with the logger argument.

`log:get`

The log:get command show the current log level of a logger.

By default, the log level showed is the one from the root logger:

karaf@root()> log:get
Logger | Level
--------------
ROOT   | INFO

You can specify a particular logger using the logger argument:

karaf@root()> log:get ssh
Logger | Level
--------------
ssh    | INFO

The logger argument accepts the ALL keyword to display the log level of all logger (as a list).

For instance, if you have defined your own logger in etc/org.ops4j.pax.logging.cfg file like this:

log4j.logger.my.logger = DEBUG

you can see the list of loggers with the corresponding log level:

karaf@root()> log:get ALL
Logger    | Level
-----------------
ROOT      | INFO
my.logger | DEBUG

The log:list command is an alias to log:get ALL.

`log:log`

The log:log command allows you to manually add a message in the log. It’s interesting when you create Apache Karaf scripts:

karaf@root()> log:log "Hello World"
karaf@root()> log:display
2015-07-01 07:20:16,544 | INFO  | Local user karaf | command                          | 59 - org.apache.karaf.log.command - 4.0.0 | Hello World

By default, the log level is INFO, but you can specify a different log level using the -l option:

karaf@root()> log:log -l ERROR "Hello World"
karaf@root()> log:display
2015-07-01 07:21:38,902 | ERROR | Local user karaf | command                          | 59 - org.apache.karaf.log.command - 4.0.0 | Hello World

`log:set`

The log:set command sets the log level of a logger.

By default, it changes the log level of the rootLogger:

karaf@root()> log:set DEBUG
karaf@root()> log:get
Logger | Level
--------------
ROOT   | DEBUG

You can specify a particular logger using the logger argument, after the level one:

karaf@root()> log:set INFO my.logger
karaf@root()> log:get my.logger
Logger    | Level
-----------------
my.logger | INFO

The level argument accepts any Log4j log level: TRACE, DEBUG, INFO, WARN, ERROR, FATAL.

By it also accepts the DEFAULT special keyword.

The purpose of the DEFAULT keyword is to delete the current level of the logger (and only the level, the other properties like appender are not deleted) in order to use the level of the logger parent (loggers are hierarchical).

For instance, you have defined the following loggers (in etc/org.ops4j.pax.logging.cfg file):

rootLogger=INFO,out,osgi:*
my.logger=INFO,appender1
my.logger.custom=DEBUG,appender2

You can change the level of my.logger.custom logger:

karaf@root()> log:set INFO my.logger.custom

Now we have:

rootLogger=INFO,out,osgi:*
my.logger=INFO,appender1
my.logger.custom=INFO,appender2

You can use the DEFAULT keyword on my.logger.custom logger to remove the level:

karaf@root()> log:set DEFAULT my.logger.custom

Now we have:

rootLogger=INFO,out,osgi:*
my.logger=INFO,appender1
my.logger.custom=appender2

It means that, at runtime, the my.logger.custom logger uses the level of its parent my.logger, so INFO.

Now, if we use the DEFAULT keyword with the my.logger logger:

karaf@root()> log:set DEFAULT my.logger

We have:

rootLogger=INFO,out,osgi:*
my.logger=appender1
my.logger.custom=appender2

So, both my.logger.custom and my.logger use the log level of the parent rootLogger.

It’s not possible to use the DEFAULT keyword with the rootLogger as it doesn’t have a parent.

`log:tail`

The log:tail is exactly the same as log:display but it continuously displays the log entries.

You can use the same options and arguments as for the log:display command.

By default, it displays the entries from the rootLogger:

karaf@root()> log:tail
2015-07-01 07:40:28,152 | INFO  | FelixStartLevel  | SecurityUtils                    | 16 - org.apache.sshd.core - 0.9.0 | BouncyCastle not registered, using the default JCE provider
2015-07-01 07:40:28,909 | INFO  | FelixStartLevel  | core                             | 68 - org.apache.aries.jmx.core - 1.1.1 | Starting JMX OSGi agent
2015-07-01 07:40:28,928 | INFO  | FelixStartLevel  | core                             | 68 - org.apache.aries.jmx.core - 1.1.1 | Registering MBean with ObjectName [osgi.compendium:service=cm,version=1.3,framework=org.apache.felix.framework,uuid=b44a44b7-41cd-498f-936d-3b12d7aafa7b] for service with service.id [13]
2015-07-01 07:40:28,936 | INFO  | JMX OSGi Agent   | core                             | 68 - org.apache.aries.jmx.core - 1.1.1 | Registering org.osgi.jmx.service.cm.ConfigurationAdminMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@27cc75cb with name osgi.compendium:service=cm,version=1.3,framework=org.apache.felix.framework,uuid=b44a44b7-41cd-498f-936d-3b12d7aafa7b

To exit from the log:tail command, just type CTRL-C.

4.7.5. JMX LogMBean

All actions that you can perform with the log:* command can be performed using the LogMBean.

The LogMBean object name is org.apache.karaf:type=log,name=*.

Attributes

Level attribute is the level of the ROOT logger.

Operations

getLevel(logger) to get the log level of a specific logger. As this operation supports the ALL keyword, it returns a Map with the level of each logger.
setLevel(level, logger) to set the log level of a specific logger. This operation supports the DEFAULT keyword as for the log:set command.

4.7.6. Advanced configuration

Filters

You can use filters on an appender. Filters allow log events to be evaluated to determine if or how they should be published.

Log4j provides ready to use filters:

The DenyAllFilter (org.apache.log4j.varia.DenyAllFilter) drops all logging events. You can add this filter to the end of a filter chain to switch from the default "accept all unless instructed otherwise" filtering behaviour to a "deny all unless instructed otherwise" behaviour.
The LevelMatchFilter (org.apache.log4j.varia.LevelMatchFilter is a very simple filter based on level matching. The filter admits two options LevelToMatch and AcceptOnMatch. If there is an exact match between the value of the LevelToMatch option and the level of the logging event, then the event is accepted in case the AcceptOnMatch option value is set to true. Else, if the AcceptOnMatch option value is set to false, the log event is rejected.
The LevelRangeFilter (org.apache.log4j.varia.LevelRangeFilter is a very simple filter based on level matching, which can be used to reject messages with priorities outside a certain range. The filter admits three options LevelMin, LevelMax and AcceptOnMatch. If the log event level is between LevelMin and LevelMax, the log event is accepted if AcceptOnMatch is true, or rejected if AcceptOnMatch is false.
The StringMatchFilter (org.apache.log4j.varia.StringMatchFilter) is a very simple filter based on string matching. The filter admits two options StringToMatch and AcceptOnMatch. If there is a match between the StringToMatch and the log event message, the log event is accepted if AcceptOnMatch is true, or rejected if AcceptOnMatch is false.

The filter is defined directly on the appender, in the etc/org.ops4j.pax.logging.cfg configuration file.

The format to use it:

log4j.appender.[appender-name].filter.[filter-name]=[filter-class]
log4j.appender.[appender-name].filter.[filter-name].[option]=[value]

For instance, you can use the f1 LevelRangeFilter on the out default appender:

log4j.appender.out.filter.f1=org.apache.log4j.varia.LevelRangeFilter
log4j.appender.out.filter.f1.LevelMax=FATAL
log4j.appender.out.filter.f1.LevelMin=DEBUG

Thanks to this filter, the log files generated by the out appender will contain only log messages with a level between DEBUG and FATAL (the log events with TRACE as level are rejected).

Nested appenders

A nested appender is a special kind of appender that you use "inside" another appender. It allows you to create some kind of "routing" between a chain of appenders.

The most used "nested compliant" appender are:

The AsyncAppender (org.apache.log4j.AsyncAppender) logs events asynchronously. This appender collects the events and dispatch them to all the appenders that are attached to it.
The RewriteAppender (org.apache.log4j.rewrite.RewriteAppender) forwards log events to another appender after possibly rewriting the log event.

This kind of appender accepts an appenders property in the appender definition:

log4j.appender.[appender-name].appenders=[comma-separated-list-of-appender-names]

For instance, you can create a AsyncAppender named async and asynchronously dispatch the log events to a JMS appender:

log4j.appender.async=org.apache.log4j.AsyncAppender
log4j.appender.async.appenders=jms

log4j.appender.jms=org.apache.log4j.net.JMSAppender
...

Error handlers

Sometime, appenders can fail. For instance, a RollingFileAppender tries to write to the filesystem but the filesystem is full, or a JMS appender tries to send a message but the JMS broker is not there.

As logs can be very critical to you, you have to be informed that the log appender failed.

This is the purpose of the error handlers. Appenders may delegate their error handling to error handlers, giving a chance to react to the errors of the appender.

You have two error handlers available:

The OnlyOnceErrorHandler (org.apache.log4j.helpers.OnlyOnceErrorHandler) implements log4j’s default error handling policy which consists of emitting a message for the first error in an appender and ignoring all following errors. The error message is printed on System.err. This policy aims at protecting an otherwise working application from being flooded with error messages when logging fails.
The FallbackErrorHandler (org.apache.log4j.varia.FallbackErrorHandler) allows a secondary appender to take over if the primary appender fails. The error message is printed on System.err, and logged in the secondary appender.

You can define the error handler that you want to use for each appender using the errorhandler property on the appender definition itself:

log4j.appender.[appender-name].errorhandler=[error-handler-class]
log4j.appender.[appender-name].errorhandler.root-ref=[true|false]
log4j.appender.[appender-name].errorhandler.logger-ref=[logger-ref]
log4j.appender.[appender-name].errorhandler.appender-ref=[appender-ref]

OSGi specific MDC attributes

The sift appender is a OSGi oriented appender allowing you to split the log events based on MDC (Mapped Diagnostic Context) attributes.

MDC allows you to distinguish the different source of log events.

The sift appender provides OSGi oritend MDC attributes by default:

bundle.id is the bundle ID
bundle.name is the bundle symbolic name
bundle.version is the bundle version

You can use these MDC properties to create a log file per bundle:

log4j.appender.sift=org.apache.log4j.sift.MDCSiftingAppender
log4j.appender.sift.key=bundle.name
log4j.appender.sift.default=karaf
log4j.appender.sift.appender=org.apache.log4j.FileAppender
log4j.appender.sift.appender.layout=org.apache.log4j.PatternLayout
log4j.appender.sift.appender.layout.ConversionPattern=%d{ABSOLUTE} | %-5.5p | %-16.16t | %-32.32c{1} | %-32.32C %4L | %m%n
log4j.appender.sift.appender.file=${karaf.log}/$\\{bundle.name\\}.log
log4j.appender.sift.appender.append=true

Enhanced OSGi stack trace renderer

By default, Apache Karaf provides a special stack trace renderer, adding some OSGi specific specific information.

In the stack trace, in addition of the class throwing the exception, you can find a pattern [id:name:version] at the end of each stack trace line, where:

id is the bundle ID
name is the bundle name
version is the bundle version

It’s very helpful to diagnosing the source of an issue.

For instance, in the following IllegalArgumentException stack trace, we can see the OSGi details about the source of the exception:

java.lang.IllegalArgumentException: Command not found:  *:foo
	at org.apache.felix.gogo.runtime.shell.Closure.execute(Closure.java:225)[21:org.apache.karaf.shell.console:4.0.0]
	at org.apache.felix.gogo.runtime.shell.Closure.executeStatement(Closure.java:162)[21:org.apache.karaf.shell.console:4.0.0]
	at org.apache.felix.gogo.runtime.shell.Pipe.run(Pipe.java:101)[21:org.apache.karaf.shell.console:4.0.0]
	at org.apache.felix.gogo.runtime.shell.Closure.execute(Closure.java:79)[21:org.apache.karaf.shell.console:4.0.0]
	at org.apache.felix.gogo.runtime.shell.CommandSessionImpl.execute(CommandSessionImpl.java:71)[21:org.apache.karaf.shell.console:4.0.0]
	at org.apache.karaf.shell.console.jline.Console.run(Console.java:169)[21:org.apache.karaf.shell.console:4.0.0]
	at java.lang.Thread.run(Thread.java:637)[:1.7.0_21]

Custom appenders

You can use your own appenders in Apache Karaf.

The easiest way to do that is to package your appender as an OSGi bundle and attach it as a fragment of the org.ops4j.pax.logging.pax-logging-service bundle.

For instance, you create MyAppender:

public class MyAppender extends AppenderSkeleton {
...
}

You compile and package as an OSGi bundle containing a MANIFEST looking like:

Manifest:
Bundle-SymbolicName: org.mydomain.myappender
Fragment-Host: org.ops4j.pax.logging.pax-logging-service
...

Copy your bundle in the Apache Karaf system folder. The system folder uses a standard Maven directory layout: groupId/artifactId/version.

In the etc/startup.properties configuration file, you define your bundle in the list before the pax-logging-service bundle.

You have to restart Apache Karaf with a clean run (purging the data folder) in order to reload the system bundles. You can now use your appender directly in etc/org.ops4j.pax.logging.cfg configuration file.

4.8. Configuration

4.8.1. Environment Variables & System Properties

Apache Karaf uses default configuration properties location in etc folder (KARAF_ETC).

You can override any configuration using either environment variables or system properties.

Basically, Apache Karaf is looking for property in env and system properties.

You can use PID_PROPERTY=VALUE syntax for environment variable and pid.property=value for system properties.

For instance, the following statement will override value sshPort in etc/org.apache.karaf.shell.cfg:

# environment variable
export ORG_APACHE_KARAF_SHELL_SSHPORT=8102

# system property
-Dorg.apache.karaf.shell.sshPort=8102

You can override any configuration property using this mechanism.

It’s possible to "append" a new value based on the content of a configuration property. For instance, you want to add a new features repository to the default value (define the etc/org.apache.karaf.features.cfg config file featuresRepositories property. You can use the following env variable:

export ORG_APACHE_KARAF_FEATURES_FEATURESREPOSITORIES='${featuresRepositories},mvn:org.apache.karaf.decanter/apache-karaf-decanter/2.5.0/xml/features'

It means that Karaf will take value of featuresRepositories property contained in the etc/org.apache.karaf.features.cfg configuration file and add mvn:org.apache.karaf.decanter/apache-karaf-decanter/2.5.0/xml/features.

4.8.2. Files

Apache Karaf stores and loads all configuration in files located in the etc folder.

By default, the etc folder is relative to the KARAF_BASE folder. You can define another location using the KARAF_ETC variable.

Each configuration is identified by a ID (the ConfigAdmin PID). The configuration file names follow the pid.cfg name convention.

For instance, etc/org.apache.karaf.shell.cfg means that this file is the file used by the configuration with org.apache.karaf.shell as PID.

A configuration file is a properties file containing key/value pairs:

property=value

Properties can be referenced inside configuration files using the syntax ${<name>}. Default and alternate values can be specified using ${<name>:-<default_value>} and ${<name>:+<alternate_value>} syntaxes respectively.

existing_property=baz
property1=${missing_property:-foo}   # "foo"
property2=${missing_property:+foo}   # empty string
property3=${existing_property:-bar}  # "baz"
property4=${existing_property:+bar}  # "bar"

Apache Karaf will look for system property as well. For instance, the following:

key=${foo}

means that key will contain bar if you start Karaf with -Dfoo=bar.

Environment variables can be referenced inside configuration files using the syntax ${env:<name>} (e.g. property=${env:FOO} will set "property" to the value of the enviroment variable "FOO"). Default and alternate values can be defined for them as well using the same syntax as above.

Apache Karaf also supports other syntax, supporting:

files on disk, for example to be used with Kubernetes secrets
environment variables
properties defined in etc/config.properties
system properties

Secret Files

Usually secrets (for example when provided by Kubernetes) will surface as files in a location. By default, the location is etc folder. However, you can point to any folder. The configuration is located in etc/config.properties:

org.apache.felix.configadmin.plugin.interpolation.secretsdir=${karaf.etc}

The file contents are opaque and contain the secret value as-is. To use content of a secret file in a configuration property, you can do:

user=my-user
password=$[secret:db.password]

The content of etc/db.password will by used as value for password property.

Environment variables

Exactly the same as ${env:USER}, you can use $[env:USER] syntax in a property:

greeting="Hello $[env:USER]"

With this syntax, default value is passed like this:

greeting="Hello $[env:USER;default=John]"

It’s also possible to define the type of the property:

port=$[env:PORT;type=Integer]

System properties

System property can be passed with -Dfoo=bar to the Karaf process or define in etc/config.properties.

You can use these properties using the following syntax:

port=$[prop:my.port;default=8080]

cfg files

In Apache Karaf, a configuration is a PID with a set of properties attached.

Apache Karaf automatically loads all *.cfg files from the etc folder.

You can configure the behaviour of the configuration files using some dedicated properties in the etc/config.properties configuration file:

...
#
# Configuration FileMonitor properties
#
felix.fileinstall.enableConfigSave = true
felix.fileinstall.dir    = ${karaf.etc}
felix.fileinstall.filter = .*\\.(cfg|config)
felix.fileinstall.poll   = 1000
felix.fileinstall.noInitialDelay = true
felix.fileinstall.log.level = 3
felix.fileinstall.log.default = jul
...

felix.fileinstall.enableConfigSave flush back in the configuration file the changes performed directly on the configuration service (ConfigAdmin). If true, any change (using config:* commands, MBeans, OSGi service) is persisted back in the configuration false. Default is true.
felix.fileinstall.dir is the directory where Apache Karaf is looking for configuration files. Default is ${karaf.etc} meaning the value of the KARAF_ETC variable.
felix.fileinstall.filter is the file name pattern used to load only some configuration files. Only files matching the pattern will be loaded. Default value is .*\\.(cfg|config) meaning *.cfg and *.config files.
felix.fileinstall.poll is the polling interval (in milliseconds). Default value is 1000 meaning that Apache Karaf "re-loads" the configuration files every second.
felix.fileinstall.noInitialDelay is a flag indicating if the configuration file polling starts as soon as Apache Karaf starts or wait for a certain time. If true, Apache Karaf polls the configuration files as soon as the configuration service starts.
felix.fileinstall.log.level is the log message verbosity level of the configuration polling service. The higher this value, the more verbose the configuration service is.
felix.fileinstall.log.default is the logging framework to use, jul meaning Java Util Logging.

You can change the configuration at runtime by directly editing the configuration file.

You can also do the same using the config:* commands or the ConfigMBean.

Apache Karaf persists configuration using its own persistence manager in the case of when available persistence managers do not support that. Configuration files are placed by default in KARAF_ETC, but it could be overridden via variable storage in etc/org.apache.karaf.config.cfg. If you want to disable the Karaf persistence manager, set the storage variable to an empty string (storage=).

4.8.3. `config:*` commands

Apache Karaf provides a set of commands to manage the configuration.

`config:list`

config:list displays the list of all configurations available, or the properties in a given configuration (PID).

Without the query argument, the config:list command display all configurations, with PID, attached bundle and properties defined in the configuration:

karaf@root()> config:list
----------------------------------------------------------------
Pid:            org.apache.karaf.service.acl.command.system.start-level
BundleLocation: mvn:org.apache.karaf.shell/org.apache.karaf.shell.console/4.0.0
Properties:
   service.guard = (&(osgi.command.scope=system)(osgi.command.function=start-level))
   * = *
   start-level = admin                           # admin can set any start level, including < 100
   start-level[/[^0-9]*/] = viewer               # viewer can obtain the current start level
   execute[/.*/,/[^0-9]*/] = viewer               # viewer can obtain the current start level
   execute = admin                           # admin can set any start level, including < 100
   service.pid = org.apache.karaf.service.acl.command.system.start-level
   start-level[/.*[0-9][0-9][0-9]+.*/] = manager # manager can set startlevels above 100
   execute[/.*/,/.*[0-9][0-9][0-9]+.*/] = manager # manager can set startlevels above 100
----------------------------------------------------------------
Pid:            org.apache.karaf.log
BundleLocation: mvn:org.apache.karaf.log/org.apache.karaf.log.core/4.0.0
Properties:
   service.pid = org.apache.karaf.log
   size = 500
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg
...

The query argument accepts a query using a LDAP syntax.

For instance, you can display details on one specific configuration using the following filter:

karaf@root()> config:list "(service.pid=org.apache.karaf.log)"
----------------------------------------------------------------
Pid:            org.apache.karaf.log
BundleLocation: mvn:org.apache.karaf.log/org.apache.karaf.log.core/4.0.0
Properties:
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   service.pid = org.apache.karaf.log
   size = 500

`config:edit`

config:edit is the first command to do when you want to change a configuration. config:edit command put you in edit mode for a given configuration.

For instance, you can edit the org.apache.karaf.log configuration:

karaf@root()> config:edit org.apache.karaf.log

The config:edit command doesn’t display anything, it just puts you in configuration edit mode. You are now ready to use other config commands (like config:property-append, config:property-delete, config:property-set, …).

If you provide a configuration PID that doesn’t exist yet, Apache Karaf will create a new configuration (and so a new configuration file) automatically.

All changes that you do in configuration edit mode are stored in your console session: the changes are not directly applied in the configuration. It allows you to "commit" the changes (see config:update command) or "rollback" and cancel your changes (see config:cancel command).

`config:property-list`

The config:property-list lists the properties for the currently edited configuration.

Assuming that you edited the org.apache.karaf.log configuration, you can do:

karaf@root()> config:property-list
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   service.pid = org.apache.karaf.log
   size = 500

`config:property-set`

The config:property-set command updates the value of a given property in the currently edited configuration.

For instance, to change the value of the size property of the previously edited org.apache.karaf.log configuration, you can do:

karaf@root()> config:property-set size 1000
karaf@root()> config:property-list
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   service.pid = org.apache.karaf.log
   size = 1000

If the property doesn’t exist, the config:property-set command creates the property.

You can use config:property-set command outside the configuration edit mode, by specifying the -p (for configuration pid) option:

karaf@root()> config:property-set -p org.apache.karaf.log size 1000
karaf@root()> config:list "(service.pid=org.apache.karaf.log)"
----------------------------------------------------------------
Pid:            org.apache.karaf.log
BundleLocation: mvn:org.apache.karaf.log/org.apache.karaf.log.core/4.0.0
Properties:
   service.pid = org.apache.karaf.log
   size = 1000
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg

Note	Using the `pid` option, you bypass the configuration commit and rollback mechanism.

`config:property-append`

The config:property-append is similar to config:property-set command, but instead of completely replacing the property value, it appends a string at the end of the property value.

For instance, to add 1 at the end of the value of the size property in org.apache.karaf.log configuration (and so have 5001 for the value instead of 500), you can do:

karaf@root()> config:property-append size 1
karaf@root()> config:property-list
   service.pid = org.apache.karaf.log
   size = 5001
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg

Like the config:property-set command, if the property doesn’t exist, the config:property-set command creates the property.

You can use the config:property-append command outside the configuration edit mode, by specifying the -p (for configuration pid) option:

karaf@root()> config:property-append -p org.apache.karaf.log size 1
karaf@root()> config:list "(service.pid=org.apache.karaf.log)"
----------------------------------------------------------------
Pid:            org.apache.karaf.log
BundleLocation: mvn:org.apache.karaf.log/org.apache.karaf.log.core/4.0.0
Properties:
   service.pid = org.apache.karaf.log
   size = 5001
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg

Note	Using the `pid` option, you bypass the configuration commit and rollback mechanism.

`config:property-delete`

The config:property-delete command deletes a property in the currently edited configuration.

For instance, you previously added a test property in org.apache.karaf.log configuration. To delete this test property, you do:

karaf@root()> config:property-set test test
karaf@root()> config:property-list
   service.pid = org.apache.karaf.log
   size = 500
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg
   test = test
karaf@root()> config:property-delete test
karaf@root()> config:property-list
   service.pid = org.apache.karaf.log
   size = 500
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg

You can use the config:property-delete command outside the configuration edit mode, by specifying the -p (for configuration pid) option:

karaf@root()> config:property-delete -p org.apache.karaf.log test

`config:update` and `config:cancel`

When you are in the configuration edit mode, all changes that you do using config:property* commands are stored in "memory" (actually in the console session).

Thanks to that, you can "commit" your changes using the config:update command. The config:update command will commit your changes, update the configuration, and (if possible) update the configuration files.

For instance, after changing org.apache.karaf.log configuration with some config:property* commands, you have to commit your change like this:

karaf@root()> config:edit org.apache.karaf.log
karaf@root()> config:property-set test test
karaf@root()> config:update
karaf@root()> config:list "(service.pid=org.apache.karaf.log)"
----------------------------------------------------------------
Pid:            org.apache.karaf.log
BundleLocation: mvn:org.apache.karaf.log/org.apache.karaf.log.core/4.0.0
Properties:
   service.pid = org.apache.karaf.log
   size = 500
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg
   test = test

On the other hand, if you want to "rollback" your changes, you can use the config:cancel command. It will cancel all changes that you did, and return to the configuration state just before the config:edit command. The config:cancel exits from the edit mode.

For instance, you added the test property in the org.apache.karaf.log configuration, but it was a mistake:

karaf@root()> config:edit org.apache.karaf.log
karaf@root()> config:property-set test test
karaf@root()> config:cancel
karaf@root()> config:list "(service.pid=org.apache.karaf.log)"
----------------------------------------------------------------
Pid:            org.apache.karaf.log
BundleLocation: mvn:org.apache.karaf.log/org.apache.karaf.log.core/4.0.0
Properties:
   service.pid = org.apache.karaf.log
   size = 500
   pattern = %d{ISO8601} | %-5.5p | %-16.16t | %-32.32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n
   felix.fileinstall.filename = file:/opt/apache-karaf-4.0.0/etc/org.apache.karaf.log.cfg

`config:delete`

The config:delete command completely deletes an existing configuration. You don’t have to be in edit mode to delete a configuration.

For instance, you added my.config configuration:

karaf@root()> config:edit my.config
karaf@root()> config:property-set test test
karaf@root()> config:update
karaf@root()> config:list "(service.pid=my.config)"
----------------------------------------------------------------
Pid:            my.config
BundleLocation: null
Properties:
   service.pid = my.config
   test = test

You can delete the my.config configuration (including all properties in the configuration) using the config:delete command:

karaf@root()> config:delete my.config
karaf@root()> config:list "(service.pid=my.config)"
karaf@root()>

`config:meta`

The config:meta command lists the meta type information related to a given configuration.

It allows you to get details about the configuration properties: key, name, type, default value, and description:

karaf@root()> config:meta -p org.apache.karaf.log
Meta type informations for pid: org.apache.karaf.log
key     | name    | type   | default                                                              | description
---------------------------------------------------------------------------------------------------------------------------------------
size    | Size    | int    | 500                                                                  | size of the log to keep in memory
pattern | Pattern | String | %d{ABSOLUTE} | %-5.5p | %-16.16t | %-32.32c{1} | %-32.32C %4L | %m%n | Pattern used to display log entries

4.8.4. JMX ConfigMBean

On the JMX layer, you have a MBean dedicated to the management of the configurations: the ConfigMBean.

The ConfigMBean object name is: org.apache.karaf:type=config,name=*.

Attributes

The Configs attribute is a list of all configuration PIDs.

Operations

listProperties(pid) returns the list of properties (property=value formatted) for the configuration pid.
deleteProperty(pid, property) deletes the property from the configuration pid.
appendProperty(pid, property, value) appends value at the end of the value of the property of the configuration pid.
setProperty(pid, property, value) sets value for the value of the property of the configuration pid.
delete(pid) deletes the configuration identified by the pid.
create(pid) creates an empty (without any property) configuration with pid.
update(pid, properties) updates a configuration identified with pid with the provided properties map.

4.9. Artifacts repositories and URLs

The main information provided by a feature is the set of OSGi bundles that defines the application. Such bundles are URLs pointing to the actual bundle jars. For example, one would write the following definition:

<bundle>https://repo1.maven.org/maven2/org/apache/servicemix/nmr/org.apache.servicemix.nmr.api/1.0.0-m2/org.apache.servicemix.nmr.api-1.0.0-m2.jar</bundle>

Doing this will make sure the above bundle is installed while installing the feature.

However, Karaf provides several URL handlers, in addition to the usual ones (file, http, etc…). One of these is the Maven URL handler, which allow reusing maven repositories to point to the bundles.

You can deploy bundles from file system without using Maven

As we can use file: as protocol handler to deploy bundles, you can use the following syntax to deploy bundles when they are located in a directory which is not available using Maven

<bundle>file:base/bundles/org.apache.servicemix.nmr.api-1.0.0-m2.jar</bundle>

Note: The path is relative to the Apache Karaf installation directory

4.9.1. Maven URL Handler

The equivalent of the above bundle would be:

<bundle>mvn:org.apache.servicemix.nmr/org.apache.servicemix.nmr.api/1.0.0-m2</bundle>

In addition to being less verbose, the Maven url handlers can also resolve snapshots and can use a local copy of the jar if one is available in your Maven local repository.

The org.ops4j.pax.url.mvn bundle resolves mvn URLs. It can be configured using the file etc/org.ops4j.pax.url.mvn.cfg. Full reference of org.ops4j.pax.url.mvn PID configuration can be found on the pax-web Wiki page.

The most important property is:

org.ops4j.pax.url.mvn.repositories : Comma separated list of remote repository URLs that are checked in order of occurence when resolving maven artifacts

Two other significant properties are:

org.ops4j.pax.url.mvn.defaultRepositories : Comma separated list of locations that are checked before querying remote repositories. These can be treated as read-only repositories, as nothing is written there during artifact resolution.
org.ops4j.pax.url.mvn.localRepository : by default (implicitly) it’s the standard ~/.m2/repository location. This local repository is used to store artifacts downloaded from one of remote repositories, so at next resolution attempt no remote request is issued.

By default, snapshots are disabled. To enable an URL for snapshots append @snapshots to a repository URI. For example

org.ops4j.pax.url.mvn.repositories = http://www.example.org/repo@snapshots

Repositories on the local machine are supported through file:/ URLs.

4.9.2. Maven configuration commands

Full configuration of org.ops4j.pax.url.mvn bundle can be done using org.ops4j.pax.url.mvn PID (see etc/org.ops4j.pax.url.mvn.cfg file). This however may be cumbersome in some scenarios.

In order to make the user’s life easier and to provide more domain oriented approach, Karaf provides several shell commands that makes Maven configuration easier.

maven:summary

This command shows a quick summary about current org.ops4j.pax.url.mvn PID configuration. For example:

karaf@root()> maven:summary -s

Option                    │ Value                                                          │ Source
──────────────────────────┼────────────────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────────────────────────────
Local repository          │ /home/ggrzybek/.m2/repository                                  │ Implicit ${user.home}/.m2/repository
Settings file             │ /home/ggrzybek/.m2/settings.xml                                │ Implicit ${user.home}/.m2/settings.xml
Security settings file    │ /home/ggrzybek/.m2/settings-security.xml                       │ Implicit ${user.home}/.m2/settings-security.xml
Global update policy      │                                                                │ Implicit "never", but doesn't override repository-specific value
Global checksum policy    │ warn                                                           │ Default "warn"
Update releases           │ false                                                          │ Default "false"
Require Config Admin      │ true                                                           │ BundleContext property (org.ops4j.pax.url.mvn.requireConfigAdminConfig)
Use fallback repository   │ false                                                          │ Explicit org.ops4j.pax.url.mvn PID configuration (org.ops4j.pax.url.mvn.useFallbackRepositories)
Offline mode              │ false                                                          │ Default "false"
SSL/TLS certificate check │ true                                                           │ Explicit org.ops4j.pax.url.mvn PID configuration (org.ops4j.pax.url.mvn.certificateCheck)
Remote repositories       │ https://repo1.maven.org/maven2/                                │ PID configuration
                          │ https://repository.apache.org/content/groups/snapshots-group/  │ PID configuration
                          │ https://oss.sonatype.org/content/repositories/snapshots/       │ PID configuration
                          │ https://oss.sonatype.org/content/repositories/ops4j-snapshots/ │ PID configuration
Default repositories      │ file:/data/servers/apache-karaf-4.2.0-SNAPSHOT/system/         │ PID configuration
                          │ file:/data/servers/apache-karaf-4.2.0-SNAPSHOT/data/kar/       │ PID configuration
HTTP proxies              │ proxy.everfree.forest:3128                                     │ Maven XML settings

-s option show where the value of the option come from. It may be implicit, explicit or default. We can also see whether the value was configured in PID or in settings.xml file.
-p option uses original option names from org.ops4j.pax.url.mvn PID instead of descriptive option names
-d option shows additional description, explaining what given option should be used for
-x option turns on password display - if there’s master password configured, it’ll be displayed in clear text. This option may be used only by user with admin role.

maven:repository-list

This command displays all configured Maven repositories - in a much more readable way than the plain config:proplist --pid org.ops4j.pax.url.mvn command does.

karaf@root()> maven:repository-list -v

== Remote repositories
ID                              │ URL                                                            │ Releases    │ Snapshots   │ Defined in
────────────────────────────────┼────────────────────────────────────────────────────────────────┼─────────────┼─────────────┼───────────
central                         │ https://repo1.maven.org/maven2/                                │ yes (daily) │ no          │ PID
apache                          │ https://repository.apache.org/content/groups/snapshots-group/  │ no          │ yes (daily) │ PID
sonatype.snapshots.deploy       │ https://oss.sonatype.org/content/repositories/snapshots/       │ no          │ yes (daily) │ PID
ops4j.sonatype.snapshots.deploy │ https://oss.sonatype.org/content/repositories/ops4j-snapshots/ │ no          │ yes (daily) │ PID
special                         │ https://repository.everfree.forest/                            │ yes (daily) │ no          │ SETTINGS

== Default repositories
ID                      │ URL                                                      │ Releases    │ Snapshots
────────────────────────┼──────────────────────────────────────────────────────────┼─────────────┼────────────
system.repository       │ file:/data/servers/apache-karaf-4.2.0-SNAPSHOT/system/   │ yes (daily) │ yes (daily)
kar.repository          │ file:/data/servers/apache-karaf-4.2.0-SNAPSHOT/data/kar/ │ yes (daily) │ yes (daily)
child.system.repository │ file:/data/servers/apache-karaf-4.2.0-SNAPSHOT/system/   │ yes (daily) │ yes (daily)

-v option shows additional information about policies related to a given repository
-x shows credentials for a given repository (if defined)

maven:password

org.ops4j.pax.url.mvn bundle uses the Aether library to handle Maven resolution. It uses the settings.xml file if credentials have to be used when accessing remote Maven repositories. This isn’t done by org.ops4j.pax.url.mvn, but by Aether itself (or rather maven-settings library). When dealing with the settings.xml file, passwords that are stored there may need to be decrypted. Outside of Karaf, we can use mvn -emp and mvn -ep passwords and manually configure ~/.m2/settings-security.xml file.

Karaf makes the task of managing credentials easier.

In order to use encrypted repository (or http proxy) passwords inside settings.xml file, Maven must know the master password stored inside settings-security.xml file. This file isn’t usually present inside ~/.m2 directory and if there’s a need to use it, one has to be created manually.

Here’s the way to encrypt the Maven master password (which is used to encrypt ordinary passwords for repository or http proxies):

karaf@root()> maven:password -emp
Master password to encrypt: *****
Encrypted master password: {y+p9TiYuwVEHMHV14ej0Ni34zBnXXQrIOqjww/3Ro6U=}

The above usage simply prints the encrypted master password. We can however make this password persistent. This will result in the creation of a new settings-security.xml file and a change in the org.ops4j.pax.url.mvn.security property.

Note	Karaf maven commands will never overwrite your current `~/.m2/settings.xml` or `~/.m2/settings-security.xml` files. If there’s a need to change these files, maven commands will make a copy of the existing file and set relevant `org.ops4j.pax.url.mvn` PID options to point to new locations.

karaf@root()> maven:password -emp --persist
Maven security settings will be stored in new file. This file will be used in org.ops4j.pax.url.mvn.security property. Continue? (y/N) y
Master password to encrypt: *****
Encrypted master password: {lPPIFSUcPrMHnhwdauttAJYZcOe1D9sYGj4rwoaTwnY=}
New security settings stored in "/data/servers/apache-karaf-4.2.0-SNAPSHOT/data/cache/bundle53/data/maven-security-settings-1498120766139.xml"
karaf@root()> maven:summary -x

Option                    │ Value
──────────────────────────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────
...
Security settings file    │ /data/servers/apache-karaf-4.2.0-SNAPSHOT/data/cache/bundle53/data/maven-security-settings-1498120766139.xml
Master password           │ admin
...

Now, when Maven master password is set, we can encrypt ordinary passwords that may be then used when defining/changing remote repositories or http proxies:

karaf@root()> maven:password -ep
Password to encrypt: *****
Encrypted password: {fHl8U3pINkEH7RR1CufRT+utj5gJHfqsRgd6wTo92Eo=}
You can use this encrypted password when defining repositories and proxies

Configuring repositories (default and remote)

As mentioned before, there are two kinds of repositories that are used/queried by org.ops4j.pax.url.mvn bundle when resolving mvn: based URIs:

default repositories: These are read-only local repositories that are simply queried before performing any remote access. The best example of such repository is $KARAF_HOME/system directory.
remote repositories: These are well-known Maven remote repositories - usually accessible over http(s) protocol. Popular repositories are Sonatype Nexus or JFrog Artifactory.

Both kinds of repositories may be created using the maven:repository-add command.

Here’s how a default repository may be created:

karaf@root()> maven:repository-add --default -id my.default.repository --snapshots '${karaf.home}/special-repository'

...
== Default repositories
ID                      │ URL                                                                │ Releases    │ Snapshots
────────────────────────┼────────────────────────────────────────────────────────────────────┼─────────────┼────────────
...
my.default.repository   │ file:/data/servers/apache-karaf-4.2.0-SNAPSHOT/special-repository/ │ yes (daily) │ yes (daily)

For a remote repository, we can specify more options (like credentials or update policies):

karaf@root()> maven:repository-add -idx 0 -id my.remote.repository --snapshots -up never --username admin --password '{fHl8U3pINkEH7RR1CufRT+utj5gJHfqsRgd6wTo92Eo=}' http://localhost/cloud-repository
Maven settings will be updated and org.ops4j.pax.url.mvn.settings property will change. Continue? (y/N) y
New settings stored in "/data/servers/apache-karaf-4.2.0-SNAPSHOT/data/cache/bundle53/data/maven-settings-1498121385253.xml"

karaf@root()> maven:repository-list -x

== Remote repositories
ID                              │ URL                                                            │ Username │ Password
────────────────────────────────┼────────────────────────────────────────────────────────────────┼──────────┼─────────
my.remote.repository            │ http://localhost/cloud-repository/                             │ admin    │ admin
...

In the above example, a new settings.xml file was created. The reason is that although a new repository itself was added to org.ops4j.pax.url.mvn.repositories property, the credentials had to be stored in settings.xml file:

<servers>
  <server>
    <username>admin</username>
    <password>{fHl8U3pINkEH7RR1CufRT+utj5gJHfqsRgd6wTo92Eo=}</password>
    <id>my.remote.repository</id>
  </server>
</servers>

Here’s summary of all options for maven:repository-add command:

-id mandatory identifier of repository
-d option may be used to configure default repositories instead of remote ones
-nr option disables non-SNAPSHOT artifacts resolution in this repository
-s option enables SNAPSHOT artifacts resolution in this repository
-up sets update policy for given repository (daily, always, never, interval:MINUTES)
-cp sets checksum policy for given repository (fail, warn, ignore)
-f disables confirmation prompts for commands
-idx allows to insert a repository at given position (instead of simply appending new repository at the end of current list of repositories)
-u sets username for remote repository access
-p sets password for remote repository access (may be encrypted using maven:password -ep)

After creating a repository, it may be deleted (using maven:repository-remove command) or changed (maven:repository-change command). All the options are the same as in maven:repository-add command. When removing a repository, only -id (and possibly -d) options are needed.

karaf@root()> repository-remove -d -id my.default.repository
Are you sure to remove repository with ID "my.default.repository" for URL file:/data/servers/apache-karaf-4.2.0-SNAPSHOT/special-repository/? (y/N) y

karaf@root()> repository-change -id special --username discord --password d1sc0rd
Maven settings will be updated and org.ops4j.pax.url.mvn.settings property will change. Continue? (y/N) y
New settings stored in "/data/servers/apache-karaf-4.2.0-SNAPSHOT/data/cache/bundle53/data/maven-settings-1498122026388.xml"

Configuring HTTP proxies

When accessing remote repositories using org.ops4j.pax.url.mvn (Aether library) there may be a need to let Maven/Aether know about HTTP proxies to use. HTTP proxies can’t be configured inside etc/org.ops4j.pax.url.mvn.cfg file. It has to be done in settings.xml and its location has to be set in org.ops4j.pax.url.mvn.settings PID property.

maven:http-proxy command can be used to add/change/remove HTTP proxy definition. It automatically does a copy of the existing settings.xml file and changes org.ops4j.pax.url.mvn.settings PID property.

For example:

karaf@root()> maven:http-proxy-list -x

ID       │ Host                  │ Port │ Non-proxy hosts │ Username │ Password
─────────┼───────────────────────┼──────┼─────────────────┼──────────┼─────────────
my.proxy │ proxy.everfree.forest │ 3128 │ 192.168.2.*     │ admin    │ super-secret

karaf@root()> maven:http-proxy --remove -id my.proxy
New settings stored in "/data/servers/apache-karaf-4.2.0-SNAPSHOT/data/cache/bundle53/data/maven-settings-1498122255098.xml"

No HTTP proxies configured in /data/servers/apache-karaf-4.2.0-SNAPSHOT/data/cache/bundle53/data/maven-settings-1498122255098.xml

karaf@root()> maven:http-proxy --add -id my.proxy --username discord --password '{fHl8U3pINkEH7RR1CufRT+utj5gJHfqsRgd6wTo92Eo=}' --non-proxy-hosts '127.*|192.168.*|localhost' proxy.everfree.forest:3128
New settings stored in "/data/servers/apache-karaf-4.2.0-SNAPSHOT/data/cache/bundle53/data/maven-settings-1498122328731.xml"

karaf@root()> maven:http-proxy-list -x

ID       │ Host                  │ Port │ Non-proxy hosts           │ Username │ Password
─────────┼───────────────────────┼──────┼───────────────────────────┼──────────┼─────────
my.proxy │ proxy.everfree.forest │ 3128 │ 127.*|192.168.*|localhost │ discord  │ admin

Here’s a summary of options for the maven:http-proxy command:

-id identifier of HTTP proxy
-add / --change / --remove is an operation to perform on proxy
-f disables confirmation prompts for commands
-u sets username for remote HTTP proxy
-p sets password for remote HTTP proxy (may be encrypted using maven:password -ep)
-n sets non proxy hosts option, which is |-separated list of glob patterns for IP addresses/host names that should be accessed bypassing HTTP proxy

maven:http-proxy configures for example this section in settings.xml:

<proxies>
  <proxy>
    <username>discord</username>
    <password>{fHl8U3pINkEH7RR1CufRT+utj5gJHfqsRgd6wTo92Eo=}</password>
    <port>3128</port>
    <host>proxy.everfree.forest</host>
    <nonProxyHosts>127.*|192.168.*|localhost</nonProxyHosts>
    <id>my.proxy</id>
  </proxy>
</proxies>

4.10. Provisioning

Apache Karaf supports the provisioning of applications and modules using the concept of Karaf Features.

4.10.1. Application

By provisioning an application, it means to install all modules, configuration, and transitive applications.

4.10.2. OSGi

It natively supports the deployment of OSGi applications.

An OSGi application is a set of OSGi bundles. An OSGi bundle is a regular jar file, with additional metadata in the jar MANIFEST.

In OSGi, a bundle can depend on other bundles. So, it means that to deploy an OSGi application, most of the time, you have to firstly deploy a lot of other bundles required by the application.

So, you have to find these bundles first, install the bundles. Again, these "dependency" bundles may require other bundles to satisfy their own dependencies.

More over, typically, an application requires configuration (see the [Configuration section|configuration] of the user guide). So, before being able to start your application, in addition to the dependency bundles, you have to create or deploy the configuration.

As we can see, the provisioning of an application can be very long and fastidious.

4.10.3. Feature and resolver

Apache Karaf provides a simple and flexible way to provision applications.

In Apache Karaf, the application provisioning is an Apache Karaf "feature".

A feature describes an application as:

a name
a version
a optional description (eventually with a long description)
a set of bundles
optionally a set configurations or configuration files
optionally a set of dependency features

When you install a feature, Apache Karaf installs all resources described in the feature. It means that it will automatically resolve and install all bundles, configuration, and dependency features described in the feature.

The feature resolver checks the service requirements, and installs the bundles providing the services matching the requirements. The default mode enables this behavior only for "new style" features repositories (basically, the features repositories XML with schema equal or greater to 1.3.0). It doesn’t apply for "old style" features repositories (coming from Karaf 2 or 3).

You can change the service requirements enforcement mode in etc/org.apache.karaf.features.cfg file, using the serviceRequirements property.

serviceRequirements=default

The possible values are:

disable: service requirements are completely ignored, for both "old style" and "new style" features repositories
default: service requirements are ignored for "old style" features repositories, and enabled for "new style" features repositories.
enforce: service requirements are always verified, for "old style" and "new style" features repositories.

Additionally, a feature can also define requirements. In that case, Karaf can automatically install additional bundles or features providing the capabilities to satisfy the requirements.

A feature has a complete lifecycle: install, start, stop, update, uninstall.

By default, the feature service is able to detect bundles which need to be refreshed. For instance, a bundle has to be refreshed:

when bundle A uses an import package, and bundle B is installed providing a new version of the package (matching bundle A import version range). Then bundle A has to be refreshed to use the new version of the package.
when bundle A uses an optional import package, and bundle B is installed providing this package. Then, bundle A has to be refreshed to actually use the package.
when bundle A uses a package provided by bundle B, then, bundle A will be refreshed as well. This is kind of "cascading" refresh.

Some users might be concerned about this refresh behavior, and prefer to manage refresh "by hand".

In that case, you can disable this auto refresh behavior using the autoRefresh property in etc/org.apache.karaf.features.cfg configuration file:

autoRefresh=false

By default, autoRefresh is true. Using false will disable auto refresh performed by the Karaf features service.

4.10.4. Features repositories

The features are described in a features XML or JSON descriptor. This file contains the description of a set of features.

A features descriptor is named a "features repository". Before being able to install a feature, you have to register the features repository that provides the feature (using feature:repo-add command or FeatureMBean as described later).

For instance, the following XML file (or "features repository") describes the feature1 and feature2 features:

<features name="my-features-repo" xmlns="http://karaf.apache.org/xmlns/features/v1.4.0">
  <feature name="feature1" version="1.0.0">
    <bundle>...</bundle>
    <bundle>...</bundle>
  </feature>
  <feature name="feature2" version="1.1.0">
    <feature>feature1</feature>
    <bundle>...</bundle>
  </feature>
</features>

Here’s the same descriptor in JSON format:

{
 "name": "my-features-repo",
 "feature": [
    {
        "name": "feature1",
        "version": "1.0.0",
        "bundle": [
           { "location": "..." },
           { "location": "..."
        ]
    },
    {
        "name": "feature2",
        "version": "1.1.0",
        "feature": [
            { "name": "feature1" }
        ]
        "bundle": [
            { "location": "..." }
        ]
    }
 ]
}

We can note that the features XML has a schema. Take a look on [Features XML Schema section|provisioning-schema] of the user guide for details. The feature1 feature is available in version 1.0.0, and contains two bundles. The <bundle/> element contains a URL to the bundle artifact (see [Artifacts repositories and URLs section|urls] for details). If you install the feature1 feature (using feature:install or the FeatureMBean as described later), Apache Karaf will automatically install the two bundles described. The feature2 feature is available in version 1.1.0, and contains a reference to the feature1 feature and a bundle. The <feature/> element contains the name of a feature. A specific feature version can be defined using the version attribute to the <feature/> element (<feature version="1.0.0">feature1</feature>). If the version attribute is not specified, Apache Karaf will install the latest version available. If you install the feature2 feature (using feature:install or the FeatureMBean as described later), Apache Karaf will automatically install feature1 (if it’s not already installed) and the bundle.

A feature repository is registered using the URL to the features XML file.

The features state is stored in the Apache Karaf cache (in the KARAF_DATA folder). You can restart Apache Karaf, the previously installed features remain installed and available after restart. If you do a clean restart or you delete the Apache Karaf cache (delete the KARAF_DATA folder), all previously registered features repositories and features installed will be lost: you will have to register the features repositories and install features by hand again. To prevent this behaviour, you can specify features as boot features.

4.10.5. Boot features

A boot feature is automatically installed by Apache Karaf, even if it has not been previously installed using feature:install or FeatureMBean.

The Apache Karaf features configuration is located in the etc/org.apache.karaf.features.cfg configuration file.

This configuration file contains the two properties to use to define boot features:

featuresRepositories contains a list (comma-separated) of features repositories (features XML) URLs.
featuresBoot contains a list (comma-separated) of features to install at boot.

To remove features from the featuresBoot list in the etc/org.apache.karaf.features.cfg configuration file:

Navigate to etc/org.apache.karaf.features.cfg.
Remove the undesired feature.
Restart your container.

Note	After the restart, the features will be present in the `etc/org.apache.karaf.features.cfg` configuration file, but they will not be installed and the undesired feature or behavior will no longer be present or active.

Note	Another way to clean up the `featuresBoot` is to stop Karaf, update `featuresBoot`, and remove the data folder.

4.10.6. Features upgrade

You can update a release by installing the same feature (with the same SNAPSHOT version or a different version).

Thanks to the features lifecycle, you can control the status of the feature (started, stopped, etc).

You can also use a simulation to see what the update will do.

4.10.7. Overrides

Bundles defined in features can be overridden by using a file etc/overrides.properties. Each line in the file defines one override. The syntax is: <bundle-uri>[;range="[min,max)"] The given bundle will override all bundles in feature definitions with the same symbolic name if the version of the override is greater than the version of the overridden bundle and the range matches. If no range is given then compatibility on the micro version level is assumed.

So for example the override mvn:org.ops4j.pax.logging/pax-logging-service/1.8.5 would overide pax-logging-service 1.8.3 but not 1.8.6 or 1.7.0.

4.10.8. Feature bundles

Start Level

By default, the bundles deployed by a feature will have a start-level equals to the value defined in the etc/config.properties configuration file, in the karaf.startlevel.bundle property.

This value can be "overridden" by the start-level attribute of the <bundle/> element, in the features XML.

  <feature name="my-project" version="1.0.0">
    <bundle start-level="80">mvn:com.mycompany.myproject/myproject-dao</bundle>
    <bundle start-level="85">mvn:com.mycompany.myproject/myproject-service</bundle>
  </feature>

{
    "feature": [
        {
            "name": "my-project",
            "version": "1.0.0"
            "bundle": [
                {
                    "startLevel": 80,
                    "location": "mvn:com.mycompany.myproject/myproject-dao"
                },
                {
                    "startLeve": 85,
                    "location": "mvn:com.mycompany.myproject/myproject-service"
                }
            ]
        }
    ]
}

The start-level attribute insures that the myproject-dao bundle is started before the bundles that use it.

Instead of using start-level, a better solution is to simply let the OSGi framework know what your dependencies are by defining the packages or services you need. It is more robust than setting start levels.

Simulate, Start and stop

You can simulate the installation of a feature using the -t option to feature:install command.

You can install a bundle without starting it. By default, the bundles in a feature are automatically started.

A feature can specify that a bundle should not be started automatically (the bundle stays in resolved state). To do so, a feature can specify the start attribute to false in the <bundle/> element:

  <feature name="my-project" version="1.0.0">
    <bundle start-level="80" start="false">mvn:com.mycompany.myproject/myproject-dao</bundle>
    <bundle start-level="85" start="false">mvn:com.mycompany.myproject/myproject-service</bundle>
  </feature>

{
    "feature": [
        {
            "name": "my-project",
            "version": "1.0.0"
            "bundle": [
                {
                    "startLevel": 80,
                    "start": false,
                    "location": "mvn:com.mycompany.myproject/myproject-dao"
                },
                {
                    "startLeve": 85,
                    "start": false,
                    "location": "mvn:com.mycompany.myproject/myproject-service"
                }
            ]
        }
    ]
}

Dependency

A bundle can be flagged as being a dependency, using the dependency attribute set to true on the bundle element.

This information can be used by resolvers to compute the full list of bundles to be installed.

<bundle dependency="true">...</bundle>

{
    "dependency": true,
    "location": "..."
}

The dependency flag means that the bundle will be installed only if there’s not other bundle providing the same capability.

4.10.9. Dependent features

A feature can depend on a set of other features:

  <feature name="my-project" version="1.0.0">
    <feature>other</feature>
    <bundle start-level="80" start="false">mvn:com.mycompany.myproject/myproject-dao</bundle>
    <bundle start-level="85" start="false">mvn:com.mycompany.myproject/myproject-service</bundle>
  </feature>

{
    "feature": [
        {
            "name": "my-project",
            "version": "1.0.0",
            "feature": [
                { "name": "other" }
            ],
            "bundle": [
                {
                    "startLevel": 80,
                    "start": false,
                    "location": "mvn:com.mycompany.myproject/myproject-dao"
                },
                {
                    "startLevel": 85,
                    "start": false,
                    "location": "mvn:com.mycompany.myproject/myproject-service"
                }
            ]
        }
    ]
}

When the my-project feature will be installed, the other feature will be automatically installed as well.

It’s possible to define a version range for a dependent feature:

<feature name="spring-dm">
  <feature version="[2.5.6,4)">spring</feature>
  ...
</feature>

{
    "feature": [
        {
            "name": "spring-dm",
            "feature": [
                {
                    "name": "spring",
                    "version": "[2.5.6,4)"
                }
            ]
        }
    ]
}

The feature with the highest version available in the range will be installed.

If a single version is specified, the range will be considered open-ended.

If nothing is specified, the highest available will be installed.

To specify an exact version, use a closed range such as [3.1,3.1].

Feature prerequisites

A prerequisite feature is a special kind of dependency. If you add the prerequisite attribute to dependant feature tag then it will force installation and also activation of bundles in the dependant feature before the installation of the actual feature. This may be handy in the case that bundles enlisted in a given feature are not using pre installed URLs such as wrap or war.

<feature name="foo" version="1.0.0">
    <feature prerequisite="true">bar</feature>
    ...
</feature>

{
    "name": "foo",
    "version": "1.0.0",
    "feature": [
        {
            "prerequisite": true,
            "name": "bar"
        }
    ]
}

4.10.10. Feature configurations

The <config/> element in a feature XML (or "config" in feature JSON) allows a feature to create and/or populate a configuration (identified by a configuration PID).

...
<config name="com.foo.bar">
  myProperty = myValue
</config>
...

...
"config": [
    {
        "name": "com.foo.bar",
        "value": "myProperty=myValue"
    }
]
....

The name attribute of the config element corresponds to the configuration PID (see the [Configuration section|configuration] for details).

The installation of the feature will have the same effect as dropping a file named com.foo.bar.cfg in the etc folder.

The content (value) of the config element is a set of properties, following the key=value standard.

4.10.11. Feature configuration files

Instead of using the config element, a feature can specify configfile elements.

<configfile finalname="/etc/myfile.cfg" override="false">URL</configfile>

  "configfile": [
    {
        "finalname": "/etc/myfile.cfg",
        "override": false,
        "location": "URL"
    }
  ]

Instead of directly manipulating the Apache Karaf configuration layer (as when using the config element), the configfile element takes directly a file specified by a URL, and copy the file in the location specified by the finalname attribute.

If not specified, the location is relative from the KARAF_BASE variable. It’s also possible to use variable like ${karaf.home}, ${karaf.base}, ${karaf.etc}, or even system properties.

For instance:

<configfile finalname="${karaf.etc}/myfile.cfg" override="false">URL</configfile>

  "configfile": [
    {
        "finalname": "${karaf.etc}/myfile.cfg",
        "override": false,
        "location": "URL"
    }
  ]

If the file is already present at the desired location it is kept and the deployment of the configuration file is skipped, as a already existing file might contain customization. This behaviour can be overriden by override set to true.

The file URL is any URL supported by Apache Karaf (see the [Artifacts repositories and URLs|urls] of the user guide for details).

Requirements

A feature can also specify expected requirements. The feature resolver will try to satisfy the requirements. For that, it checks the features and bundles capabilities and will automatically install the bundles to satisfy the requirements.

For instance, a feature can contain:

<requirement>osgi.ee;filter:=&quot;(&amp;(osgi.ee=JavaSE)(!(version&gt;=1.8)))&quot;</requirement>

"requirement": "osgi.ee;filter="(&(osgi.ee=JavaSE)(!(version>1.8)))"

The requirement specifies that the feature will work by only if the JDK version is not 1.8 (so basically 1.7).

The features resolver is also able to refresh the bundles when an optional dependency is satisfied, rewiring the optional import.

4.10.12. Commands

`feature:repo-list`

The feature:repo-list command lists all registered feature repositories:

karaf@root()> feature:repo-list
Repository               | URL
--------------------------------------------------------------------------------------
org.ops4j.pax.cdi-0.12.0 | mvn:org.ops4j.pax.cdi/pax-cdi-features/0.12.0/xml/features
org.ops4j.pax.web-4.1.4  | mvn:org.ops4j.pax.web/pax-web-features/4.1.4/xml/features
standard-4.0.0           | mvn:org.apache.karaf.features/standard/4.0.0/xml/features
enterprise-4.0.0         | mvn:org.apache.karaf.features/enterprise/4.0.0/xml/features
spring-4.0.0             | mvn:org.apache.karaf.features/spring/4.0.0/xml/features

Each repository has a name and the URL to the features XML.

Apache Karaf parses the features XML when you register the features repository URL (using feature:repo-add command or the FeatureMBean as described later). If you want to force Apache Karaf to reload the features repository URL (and so update the features definition), you can use the -r option:

karaf@root()> feature:repo-list -r
Reloading all repositories from their urls

Repository               | URL
--------------------------------------------------------------------------------------
org.ops4j.pax.cdi-0.12.0 | mvn:org.ops4j.pax.cdi/pax-cdi-features/0.12.0/xml/features
org.ops4j.pax.web-4.1.4  | mvn:org.ops4j.pax.web/pax-web-features/4.1.4/xml/features
standard-4.0.0           | mvn:org.apache.karaf.features/standard/4.0.0/xml/features
enterprise-4.0.0         | mvn:org.apache.karaf.features/enterprise/4.0.0/xml/features
spring-4.0.0             | mvn:org.apache.karaf.features/spring/4.0.0/xml/features

`feature:repo-add`

To register a features repository (and so having new features available in Apache Karaf), you have to use the feature:repo-add command.

The feature:repo-add command requires the name/url argument. This argument accepts:

a feature repository URL. It’s an URL directly to the features XML file. Any URL described in the [Artifacts repositories and URLs section|urls] of the user guide is supported.
a feature repository name defined in the etc/org.apache.karaf.features.repos.cfg configuration file.

The etc/org.apache.karaf.features.repos.cfg defines a list of "pre-installed/available" features repositories:

################################################################################
#
#    Licensed to the Apache Software Foundation (ASF) under one or more
#    contributor license agreements.  See the NOTICE file distributed with
#    this work for additional information regarding copyright ownership.
#    The ASF licenses this file to You under the Apache License, Version 2.0
#    (the "License"); you may not use this file except in compliance with
#    the License.  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#    limitations under the License.
#
################################################################################

#
# This file describes the features repository URL
# It could be directly installed using feature:repo-add command
#
enterprise=mvn:org.apache.karaf.features/enterprise/LATEST/xml/features
spring=mvn:org.apache.karaf.features/spring/LATEST/xml/features
cellar=mvn:org.apache.karaf.cellar/apache-karaf-cellar/LATEST/xml/features
cave=mvn:org.apache.karaf.cave/apache-karaf-cave/LATEST/xml/features
camel=mvn:org.apache.camel.karaf/apache-camel/LATEST/xml/features
camel-extras=mvn:org.apache-extras.camel-extra.karaf/camel-extra/LATEST/xml/features
cxf=mvn:org.apache.cxf.karaf/apache-cxf/LATEST/xml/features
cxf-dosgi=mvn:org.apache.cxf.dosgi/cxf-dosgi/LATEST/xml/features
cxf-xkms=mvn:org.apache.cxf.services.xkms/cxf-services-xkms-features/LATEST/xml
activemq=mvn:org.apache.activemq/activemq-karaf/LATEST/xml/features
jclouds=mvn:org.apache.jclouds.karaf/jclouds-karaf/LATEST/xml/features
openejb=mvn:org.apache.openejb/openejb-feature/LATEST/xml/features
wicket=mvn:org.ops4j.pax.wicket/features/LATEST/xml/features
hawtio=mvn:io.hawt/hawtio-karaf/LATEST/xml/features
pax-cdi=mvn:org.ops4j.pax.cdi/pax-cdi-features/LATEST/xml/features
pax-jdbc=mvn:org.ops4j.pax.jdbc/pax-jdbc-features/LATEST/xml/features
pax-jpa=mvn:org.ops4j.pax.jpa/pax-jpa-features/LATEST/xml/features
pax-web=mvn:org.ops4j.pax.web/pax-web-features/LATEST/xml/features
pax-wicket=mvn:org.ops4j.pax.wicket/pax-wicket-features/LATEST/xml/features
ecf=http://download.eclipse.org/rt/ecf/latest/site.p2/karaf-features.xml
decanter=mvn:org.apache.karaf.decanter/apache-karaf-decanter/LATEST/xml/features

You can directly provide a features repository name to the feature:repo-add command. For install, to install PAX JDBC, you can do:

karaf@root()> feature:repo-add pax-jdbc
Adding feature url mvn:org.ops4j.pax.jdbc/pax-jdbc-features/LATEST/xml/features

When you don’t provide the optional version argument, Apache Karaf installs the latest version of the features repository available. You can specify a target version with the version argument:

karaf@root()> feature:repo-add pax-jdbc 1.3.0
Adding feature url mvn:org.ops4j.pax.jdbc/pax-jdbc-features/1.3.0/xml/features

Instead of providing a features repository name defined in the etc/org.apache.karaf.features.repos.cfg configuration file, you can directly provide the features repository URL to the feature:repo-add command:

karaf@root()> feature:repo-add mvn:org.ops4j.pax.jdbc/pax-jdbc-features/1.3.0/xml/features
Adding feature url mvn:org.ops4j.pax.jdbc/pax-jdbc-features/1.3.0/xml/features

By default, the feature:repo-add command just registers the features repository, it doesn’t install any feature. If you specify the -i option, the feature:repo-add command registers the features repository and installs all features described in this features repository:

karaf@root()> feature:repo-add -i pax-jdbc

`feature:repo-refresh`

Apache Karaf parses the features repository XML when you register it (using feature:repo-add command or the FeatureMBean). If the features repository XML changes, you have to indicate to Apache Karaf to refresh the features repository to load the changes.

The feature:repo-refresh command refreshes the features repository.

Without argument, the command refreshes all features repository:

karaf@root()> feature:repo-refresh
Refreshing feature url mvn:org.ops4j.pax.cdi/pax-cdi-features/0.12.0/xml/features
Refreshing feature url mvn:org.ops4j.pax.web/pax-web-features/4.1.4/xml/features
Refreshing feature url mvn:org.apache.karaf.features/standard/4.0.0/xml/features
Refreshing feature url mvn:org.apache.karaf.features/enterprise/4.0.0/xml/features
Refreshing feature url mvn:org.apache.karaf.features/spring/4.0.0/xml/features

Instead of refreshing all features repositories, you can specify the features repository to refresh, by providing the URL or the features repository name (and optionally version):

karaf@root()> feature:repo-refresh mvn:org.apache.karaf.features/standard/4.0.0/xml/features
Refreshing feature url mvn:org.apache.karaf.features/standard/4.0.0/xml/features

karaf@root()> feature:repo-refresh pax-jdbc
Refreshing feature url mvn:org.ops4j.pax.jdbc/pax-jdbc-features/LATEST/xml/features

`feature:repo-remove`

The feature:repo-remove command removes a features repository from the registered ones.

The feature:repo-remove command requires an argument:

the features repository name (as displayed in the repository column of the feature:repo-list command output)
the features repository URL (as displayed in the URL column of the feature:repo-list command output)

karaf@root()> feature:repo-remove org.ops4j.pax.jdbc-1.3.0

karaf@root()> feature:repo-remove mvn:org.ops4j.pax.jdbc/pax-jdbc-features/1.3.0/xml/features

By default, the feature:repo-remove command just removes the features repository from the registered ones: it doesn’t uninstall the features provided by the features repository.

If you use -u option, the feature:repo-remove command uninstalls all features described by the features repository:

karaf@root()> feature:repo-remove -u org.ops4j.pax.jdbc-1.3.0

`feature:list`

The feature:list command lists all available features (provided by the different registered features repositories):

Name                          | Version                          | Required | State       | Repository               | Description
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
pax-cdi                       | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI support
pax-cdi-1.1                   | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI 1.1 support
pax-cdi-1.2                   | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI 1.2 support
pax-cdi-weld                  | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Weld CDI support
pax-cdi-1.1-weld              | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Weld CDI 1.1 support
pax-cdi-1.2-weld              | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Weld CDI 1.2 support
pax-cdi-openwebbeans          | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | OpenWebBeans CDI support
pax-cdi-web                   | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Web CDI support
pax-cdi-1.1-web               | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Web CDI 1.1 support
...

If you want to order the features by alphabetical name, you can use the -o option:

karaf@root()> feature:list -o
Name                          | Version                          | Required | State       | Repository               | Description
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
deltaspike-core               | 1.2.1                            |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Apache Deltaspike core support
deltaspike-data               | 1.2.1                            |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Apache Deltaspike data support
deltaspike-jpa                | 1.2.1                            |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Apache Deltaspike jpa support
deltaspike-partial-bean       | 1.2.1                            |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Apache Deltaspike partial bean support
pax-cdi                       | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI support
pax-cdi-1.1                   | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI 1.1 support
pax-cdi-1.1-web               | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Web CDI 1.1 support
pax-cdi-1.1-web-weld          | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Weld Web CDI 1.1 support
pax-cdi-1.1-weld              | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Weld CDI 1.1 support
pax-cdi-1.2                   | 0.12.0                           |          | Uninstalled | org.ops4j.pax.cdi-0.12.0 | Provide CDI 1.2 support
...

By default, the feature:list command displays all features, whatever their current state (installed or not installed).

Using the -i option displays only installed features:

karaf@root()> feature:list -i
Name            | Version | Required | State   | Repository     | Description
-------------------------------------------------------------------------------------------------------------------
aries-proxy     | 4.0.0   |          | Started | standard-4.0.0 | Aries Proxy
aries-blueprint | 4.0.0   | x        | Started | standard-4.0.0 | Aries Blueprint
feature         | 4.0.0   | x        | Started | standard-4.0.0 | Features Support
shell           | 4.0.0   | x        | Started | standard-4.0.0 | Karaf Shell
shell-compat    | 4.0.0   | x        | Started | standard-4.0.0 | Karaf Shell Compatibility
deployer        | 4.0.0   | x        | Started | standard-4.0.0 | Karaf Deployer
bundle          | 4.0.0   | x        | Started | standard-4.0.0 | Provide Bundle support
config          | 4.0.0   | x        | Started | standard-4.0.0 | Provide OSGi ConfigAdmin support
diagnostic      | 4.0.0   | x        | Started | standard-4.0.0 | Provide Diagnostic support
instance        | 4.0.0   | x        | Started | standard-4.0.0 | Provide Instance support
jaas            | 4.0.0   | x        | Started | standard-4.0.0 | Provide JAAS support
log             | 4.0.0   | x        | Started | standard-4.0.0 | Provide Log support
package         | 4.0.0   | x        | Started | standard-4.0.0 | Package commands and mbeans
service         | 4.0.0   | x        | Started | standard-4.0.0 | Provide Service support
system          | 4.0.0   | x        | Started | standard-4.0.0 | Provide System support
kar             | 4.0.0   | x        | Started | standard-4.0.0 | Provide KAR (KARaf archive) support
ssh             | 4.0.0   | x        | Started | standard-4.0.0 | Provide a SSHd server on Karaf
management      | 4.0.0   | x        | Started | standard-4.0.0 | Provide a JMX MBeanServer and a set of MBeans in
wrap            | 0.0.0   | x        | Started | standard-4.0.0 | Wrap URL handler

`feature:install`

The feature:install command installs a feature.

It requires the feature argument. The feature argument is the name of the feature, or the name/version of the feature. If only the name of the feature is provided (not the version), the latest version available will be installed.

karaf@root()> feature:install eventadmin

We can simulate an installation using -t or --simulate option: it just displays what it would do, but it doesn’t do it:

karaf@root()> feature:install -t -v eventadmin
Adding features: eventadmin/[4.0.0,4.0.0]
No deployment change.
  Managing bundle:
    org.apache.felix.metatype / 1.0.12

You can specify a feature version to install:

karaf@root()> feature:install eventadmin/4.0.0

By default, the feature:install command is not verbose. If you want to have some details about actions performed by the feature:install command, you can use the -v option:

karaf@root()> feature:install -v eventadmin
Adding features: eventadmin/[4.0.0,4.0.0]
No deployment change.
Done.

If a feature contains a bundle which is already installed, by default, Apache Karaf will refresh this bundle. Sometime, this refresh can cause an issue with other running applications. If you want to disable the auto-refresh of installed bundles, you can use the -r option:

karaf@root()> feature:install -v -r eventadmin
Adding features: eventadmin/[4.0.0,4.0.0]
No deployment change.
Done.

You can decide to not start the bundles installed by a feature using the -s or --no-auto-start option:

karaf@root()> feature:install -s eventadmin

`feature:start`

By default, when you install a feature, it’s automatically installed. However, you can specify the -s option to the feature:install command.

As soon as you install a feature (started or not), all packages provided by the bundles defined in the feature will be available, and can be used for the wiring in other bundles.

When starting a feature, all bundles are started, and so, the feature also exposes the services.

`feature:stop`

You can also stop a feature: it means that all services provided by the feature will be stopped and removed from the service registry. However, the packages are still available for the wiring (the bundles are in resolved state).

`feature:uninstall`

The feature:uninstall command uninstalls a feature. As the feature:install command, the feature:uninstall command requires the feature argument. The feature argument is the name of the feature, or the name/version of the feature. If only the name of the feature is provided (not the version), the latest version available will be uninstalled.

karaf@root()> feature:uninstall eventadmin

The features resolver is involved during feature uninstallation: transitive features installed by the uninstalled feature can be uninstalled themselves if not used by other feature.

4.10.13. Deployer

You can "hot deploy" a features XML by dropping the file directly in the deploy folder.

Apache Karaf provides a features deployer.

When you drop a features XML in the deploy folder, the features deployer does:

register the features XML as a features repository
the features with install attribute set to "auto" will be automatically installed by the features deployer.

For instance, dropping the following XML in the deploy folder will automatically install feature1 and feature2, whereas feature3 won’t be installed:

<?xml version="1.0" encoding="UTF-8"?>
<features name="my-features" xmlns="http://karaf.apache.org/xmlns/features/v1.3.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://karaf.apache.org/xmlns/features/v1.3.0 http://karaf.apache.org/xmlns/features/v1.3.0">

    <feature name="feature1" version="1.0" install="auto">
        ...
    </feature>

    <feature name="feature2" version="1.0" install="auto">
        ...
    </feature>

    <feature name="feature3" version="1.0">
        ...
    </feature>

</features>

4.10.14. JMX FeatureMBean

On the JMX layer, you have a MBean dedicated to the management of the features and features repositories: the FeatureMBean.

The FeatureMBean object name is: org.apache.karaf:type=feature,name=*.

Attributes

The FeatureMBean provides two attributes:

Features is a tabular data set of all features available.
Repositories is a tabular data set of all registered features repositories.

The Repositories attribute provides the following information:

Name is the name of the features repository.
Uri is the URI to the features XML for this repository.
Features is a tabular data set of all features (name and version) provided by this features repository.
Repositories is a tabular data set of features repositories "imported" in this features repository.

The Features attribute provides the following information:

Name is the name of the feature.
Version is the version of the feature.
Installed is a boolean. If true, it means that the feature is currently installed.
Bundles is a tabular data set of all bundles (bundles URL) described in the feature.
Configurations is a tabular data set of all configurations described in the feature.
Configuration Files is a tabular data set of all configuration files described in the feature.
Dependencies is a tabular data set of all dependent features described in the feature.

Operations

addRepository(url) adds the features repository with the url. The url can be a name as in the feature:repo-add command.
addRepository(url, install) adds the features repository with the url and automatically installs all bundles if install is true. The url can be a name like in the feature:repo-add command.
removeRepository(url) removes the features repository with the url. The url can be a name as in the feature:repo-remove command.
installFeature(name) installs the feature with the name.
installFeature(name, version) installs the feature with the name and version.
installFeature(name, noClean, noRefresh) installs the feature with the name without cleaning the bundles in case of failure, and without refreshing already installed bundles.
installFeature(name, version, noClean, noRefresh) ` installs the feature with the `name and version without cleaning the bundles in case of failure, and without refreshing already installed bundles.
uninstallFeature(name) uninstalls the feature with the name.
uninstallFeature(name, version) uninstalls the feature with the name and version.

Notifications

The FeatureMBean sends two kind of notifications (on which you can subscribe and react):

When a feature repository changes (added or removed).
When a feature changes (installed or uninstalled).

4.11. Deployers

The following picture describes the architecture of the deployers.

Apache Karaf polls the deploy folder for new files.

You can configure the location of the deploy folder, and the polling behaviour in the etc/org.apache.felix.fileinstall-deploy.cfg configuration file:

################################################################################
#
#    Licensed to the Apache Software Foundation (ASF) under one or more
#    contributor license agreements.  See the NOTICE file distributed with
#    this work for additional information regarding copyright ownership.
#    The ASF licenses this file to You under the Apache License, Version 2.0
#    (the "License"); you may not use this file except in compliance with
#    the License.  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#    limitations under the License.
#
################################################################################

felix.fileinstall.dir           = ${karaf.base}/deploy
felix.fileinstall.tmpdir        = ${karaf.data}/generated-bundles
felix.fileinstall.poll          = 1000
felix.fileinstall.start.level   = 80
felix.fileinstall.active.level  = 80
felix.fileinstall.log.level     = 3

felix.fileinstall.dir defines the location of the deploy folder. Default value is KARAF_BASE/deploy.
felix.fileinstall.tmpdir defines a temporary folder where the deployers store their files. Default value is KARAF_DATA/generated-bundles.
felix.fileinstall.poll defines the polling interval (in milliseconds). Default value is 1 second.

When Apache Karaf polls a file from the deploy folder, it "delegates" the file handling to a deployer.

By default, Apache Karaf provides a set of deployers:

Blueprint deployer is able to handle Blueprint XML files.
Spring deployer is able to handle Spring XML files.
Features deployer is able to handle Apache Karaf features XML files (see [Provisioning section|provisioning] for details).
KAR deployer is able to handle KAR files (see [KAR section|kar] for details).
Wrap deployer is able to handle non-OSGi jar files and turns it as OSGi bundles "on the fly".
Optionally, WAR deployer (if you install the war feature) is able to handle WAR files.

4.11.1. Blueprint deployer

The Blueprint deployer is able to handle plain Blueprint XML configuration files.

The Blueprint deployer is able to transform "on the fly" any Blueprint XML file into a valid OSGi bundle.

The generated OSGi MANIFEST will contain the following headers:

Manifest-Version: 2
Bundle-SymbolicName: [name of the file]
Bundle-Version: [version of the file]
Import-Package: [required packages]
DynamicImport-Package: *

The name and version of the file are extracted using a heuristic that will match common patterns.

For example my-config-1.0.1.xml will lead to name = my-config and version = 1.0.1.

The default imported packages are extracted from the blueprint file definition and includes all classes referenced directly.

If you need to customize the generated manifest, you can do so by including an xml element in your blueprint configuration:

<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0">
  <manifest xmlns="http://karaf.apache.org/xmlns/deployer/blueprint/v1.0.0">
    Require-Bundle= my-bundle
  </manifest>

4.11.2. Spring deployer

The Spring deployer is similar to the Blueprint deployer.

The Spring deployer is able to deploy Spring XML files.

Like the Blueprint deployer, the generated OSGi MANIFEST will contain the following headers:

Manifest-Version: 2
Bundle-SymbolicName: [name of the file]
Bundle-Version: [version of the file]
Spring-Context: *;publish-context:=false;create-asynchronously:=true
Import-Package: [required packages]
DynamicImport-Package: *

If you need to customize the generated manifest, you can do so by including a XML element in your Spring configuration:

<spring:beans ...>
  <manifest xmlns="http://karaf.apache.org/xmlns/deployer/spring/v1.0.0">
    Require-Bundle= my-bundle
  </manifest>

4.11.3. Features deployer

See the Provisioning section for details.

4.11.4. KAR deployer

See the KAR section for details.

4.11.5. War deployer

The installation of the WAR feature enables a WAR deployer.

It means that with the war feature installed, Apache Karaf is a complete OSGi WebContainer (like Tomcat) where you can deploy WAB (WebApplication Bundle) or pure WAR (WebApplication aRchive).

You can install the war feature with:

karaf@root()> feature:install war

The WAR deployer supports:

WAB files
WAR files
exploded WAR (as a directory named *.war).

The only requirement of the WAR deployer is that the archive contains the WEB-INF/web.xml file.

4.11.6. Wrap deployer

The wrap deployer allows you to "hot deploy" non-OSGi jar files ("classical" jar files) from the deploy folder.

The wrap deployer creates "on the fly" an OSGi bundle with a non-OSGi jar file.

The wrap deployer looks for jar files in the deploy folder. A jar file is considered as non-OSGi if the MANIFEST doesn’t contain the Bundle-SymbolicName and Bundle-Version attributes, or if there is no MANIFEST at all.

The wrap deployer "transforms" non-OSGi jar file into an OSGi bundle.

The wrap deployer tries to populate the Bundle-SymbolicName and Bundle-Version extracted from the jar file path.

For example, if you simply copy commons-lang-2.3.jar (which is not an OSGi bundle) into the deploy folder, you will see:

karaf@root()> la|grep -i commons-lang
80 | Active   |  80 | 2.3                   | commons-lang

If you take a look on the commons-lang headers, you can see that the bundle exports all packages with optional resolution and that Bundle-SymbolicName and Bundle-Version have been populated:

karaf@root()> bundle:headers 80

commons-lang (80)
-----------------
Specification-Title = Commons Lang
Tool = Bnd-2.1.0.20130426-122213
Specification-Version = 2.3
Specification-Vendor = Apache Software Foundation
Implementation-Version = 2.3
Generated-By-Ops4j-Pax-From = wrap:file:/opt/apache-karaf-4.0.0/deploy/commons-lang-2.3.jar$Bundle-SymbolicName=commons-lang&Bundle-Version=2.3
Implementation-Vendor-Id = org.apache
Created-By = 1.7.0_21 (Oracle Corporation)
Implementation-Title = Commons Lang
Manifest-Version = 1.0
Bnd-LastModified = 1386339925753
X-Compile-Target-JDK = 1.1
Originally-Created-By = 1.3.1_09-85 ("Apple Computer, Inc.")
Ant-Version = Apache Ant 1.6.5
Package = org.apache.commons.lang
X-Compile-Source-JDK = 1.3
Extension-Name = commons-lang
Implementation-Vendor = Apache Software Foundation

Bundle-Name = commons-lang
Bundle-SymbolicName = commons-lang
Bundle-Version = 2.3
Bundle-ManifestVersion = 2

Export-Package =
        org.apache.commons.lang;uses:=org.apache.commons.lang.exception,
        org.apache.commons.lang.builder,
        org.apache.commons.lang.enum,
        org.apache.commons.lang.enums,
        org.apache.commons.lang.exception,
        org.apache.commons.lang.math,
        org.apache.commons.lang.mutable,
        org.apache.commons.lang.text,
        org.apache.commons.lang.time,
        org,
        org.apache,
        org.apache.commons

You can specify some MANIFEST headers by specifying the headers as URL parameters.

In the URL parameters, you can specify the headers using the $ character and & to separate the different headers. For instance:

karaf@root()> bundle:install -s 'wrap:mvn:jboss/jbossall-client/4.2.3.GA/$Bundle-SymbolicName=jbossall-client&Bundle-Version=4.2.3.GA&Export-Package=org.jboss.remoting;version="4.2.3.GA",\!*'

When defined in a features.xml file, it’s necessary to escape any ampersands and quotes, or use a CDATA tag:

<bundle>wrap:mvn:jboss/jbossall-client/4.3.2.GA/$Bundle-SymbolicName=jbossall-client&amp;Bundle-Version=4.3.2.GA&amp;Export-Package=org.jboss.remoting;version=&quot;4.3.2.GA&quot;,!*</bundle>

4.12. KAR

As described in the Provisioning section, Apache Karaf features describe applications.

A feature defines different resources to resolve using URLs (for instance, bundles URLs, or configuration files URLs). As described in the [Artifacts repositories and URLs section|urls], Apache Karaf looks for artifacts (bundles, configuration files, …) in the artifact repositories. Apache Karaf may have to download artifacts from remote repositories.

Apache Karaf provides a special type of artifact that package a features XML and all resources described in the features of this XML. This artifact is named a KAR (KAraf aRchive).

A KAR file is essentially a jar (so a zip file) which contains a set of feature descriptor and bundle jar files.

A KAR file contains a repository folder containing:

a set of features XML files
the artifacts following the Maven directory structure (groupId/artifactId/version/artifactId-version.type).

For instance, the spring-4.0.0.kar contains:

~$ unzip -l spring-4.0.0.kar
Archive:  spring-4.0.0.kar
  Length      Date    Time    Name
---------  ---------- -----   ----
      143  2013-12-06 10:52   META-INF/MANIFEST.MF
    12186  2013-12-06 10:52   repository/org/apache/karaf/features/spring/4.0.0/spring-4.0.0-features.xml
   575389  2013-12-06 10:52   repository/commons-collections/commons-collections/3.2.1/commons-collections-3.2.1.jar
   232019  2013-12-06 10:52   repository/commons-beanutils/commons-beanutils/1.8.3/commons-beanutils-1.8.3.jar
   673109  2013-12-06 10:52   repository/org/apache/servicemix/bundles/org.apache.servicemix.bundles.struts/1.3.10_1/org.apache.servicemix.bundles.struts-1.3.10_1.jar
    37084  2013-12-06 10:52   repository/org/springframework/org.springframework.web.struts/3.2.4.RELEASE/org.springframework.web.struts-3.2.4.RELEASE.jar
     7411  2013-12-06 10:52   repository/org/springframework/org.springframework.instrument/3.2.4.RELEASE/org.springframework.instrument-3.2.4.RELEASE.jar
   246881  2013-12-06 10:52   repository/org/springframework/org.springframework.transaction/3.2.4.RELEASE/org.springframework.transaction-3.2.4.RELEASE.jar
    16513  2013-12-06 10:52   repository/org/apache/servicemix/bundles/org.apache.servicemix.bundles.aopalliance/1.0_6/org.apache.servicemix.bundles.aopalliance-1.0_6.jar
   881124  2013-12-06 10:52   repository/org/springframework/org.springframework.core/3.2.4.RELEASE/org.springframework.core-3.2.4.RELEASE.jar
   199240  2013-12-06 10:52   repository/org/springframework/org.springframework.expression/3.2.4.RELEASE/org.springframework.expression-3.2.4.RELEASE.jar
   614646  2013-12-06 10:52   repository/org/springframework/org.springframework.beans/3.2.4.RELEASE/org.springframework.beans-3.2.4.RELEASE.jar
   340841  2013-12-06 10:52   repository/org/springframework/org.springframework.aop/3.2.4.RELEASE/org.springframework.aop-3.2.4.RELEASE.jar
   877369  2013-12-06 10:52   repository/org/springframework/org.springframework.context/3.2.4.RELEASE/org.springframework.context-3.2.4.RELEASE.jar
   130224  2013-12-06 10:52   repository/org/springframework/org.springframework.context.support/3.2.4.RELEASE/org.springframework.context.support-3.2.4.RELEASE.jar
    30640  2013-12-06 10:52   repository/org/apache/karaf/deployer/org.apache.karaf.deployer.spring/4.0.0/org.apache.karaf.deployer.spring-4.0.0.jar
    51951  2013-12-06 10:52   repository/org/springframework/org.springframework.aspects/3.2.4.RELEASE/org.springframework.aspects-3.2.4.RELEASE.jar
   411175  2013-12-06 10:52   repository/org/springframework/org.springframework.jdbc/3.2.4.RELEASE/org.springframework.jdbc-3.2.4.RELEASE.jar
    48049  2013-12-06 10:52   repository/javax/portlet/portlet-api/2.0/portlet-api-2.0.jar
   190883  2013-12-06 10:52   repository/org/springframework/org.springframework.web.portlet/3.2.4.RELEASE/org.springframework.web.portlet-3.2.4.RELEASE.jar
   635680  2013-12-06 10:52   repository/org/springframework/org.springframework.web/3.2.4.RELEASE/org.springframework.web-3.2.4.RELEASE.jar
   645946  2013-12-06 10:52   repository/org/springframework/org.springframework.web.servlet/3.2.4.RELEASE/org.springframework.web.servlet-3.2.4.RELEASE.jar
   464911  2013-12-06 10:52   repository/org/springframework/org.springframework.test/3.2.4.RELEASE/org.springframework.test-3.2.4.RELEASE.jar
    69784  2013-12-06 10:52   repository/org/springframework/osgi/spring-osgi-web/1.2.1/spring-osgi-web-1.2.1.jar
    16030  2013-12-06 10:52   repository/org/apache/geronimo/specs/geronimo-jta_1.1_spec/1.1.1/geronimo-jta_1.1_spec-1.1.1.jar
    32359  2013-12-06 10:52   repository/org/apache/geronimo/specs/geronimo-jms_1.1_spec/1.1.1/geronimo-jms_1.1_spec-1.1.1.jar
   208684  2013-12-06 10:52   repository/org/springframework/org.springframework.jms/3.2.4.RELEASE/org.springframework.jms-3.2.4.RELEASE.jar
    75672  2013-12-06 10:52   repository/org/springframework/org.springframework.oxm/3.2.4.RELEASE/org.springframework.oxm-3.2.4.RELEASE.jar
   393607  2013-12-06 10:52   repository/org/springframework/org.springframework.orm/3.2.4.RELEASE/org.springframework.orm-3.2.4.RELEASE.jar
   338559  2013-12-06 10:52   repository/org/apache/servicemix/bundles/org.apache.servicemix.bundles.cglib/3.0_1/org.apache.servicemix.bundles.cglib-3.0_1.jar
    35859  2013-12-06 10:52   repository/org/springframework/osgi/spring-osgi-io/1.2.1/spring-osgi-io-1.2.1.jar
   362889  2013-12-06 10:52   repository/org/springframework/osgi/spring-osgi-core/1.2.1/spring-osgi-core-1.2.1.jar
   120822  2013-12-06 10:52   repository/org/springframework/osgi/spring-osgi-extender/1.2.1/spring-osgi-extender-1.2.1.jar
    24231  2013-12-06 10:52   repository/org/springframework/osgi/spring-osgi-annotation/1.2.1/spring-osgi-annotation-1.2.1.jar
    12597  2013-12-06 10:52   repository/org/apache/karaf/bundle/org.apache.karaf.bundle.springstate/4.0.0/org.apache.karaf.bundle.springstate-4.0.0.jar
    31903  2013-12-06 10:52   repository/org/eclipse/gemini/blueprint/gemini-blueprint-io/1.0.0.RELEASE/gemini-blueprint-io-1.0.0.RELEASE.jar
   578205  2013-12-06 10:52   repository/org/eclipse/gemini/blueprint/gemini-blueprint-core/1.0.0.RELEASE/gemini-blueprint-core-1.0.0.RELEASE.jar
   178525  2013-12-06 10:52   repository/org/eclipse/gemini/blueprint/gemini-blueprint-extender/1.0.0.RELEASE/gemini-blueprint-extender-1.0.0.RELEASE.jar
---------                     -------
  9803140                     38 files

As a KAR file is a simple zip file, you can create the KAR file by hand.

For instance, the following Unix commands create a very simple KAR file:

~$ mkdir repository
~$ cp /path/to/features.xml repository/features.xml
~$ cp /path/to/my.jar repository/my/project/my/1.0.0/my-1.0.0.jar
~$ zip -r my.kar repository
updating: repository/ (stored 0%)
  adding: repository/my/project/my/1.0.0/my-1.0.0.jar (deflated 0%)

You can create KAR files using Apache Maven, or directly in the Apache Karaf console.

4.12.1. Maven

Apache Karaf provides a Maven plugin: karaf-maven-plugin.

The Apache Karaf Maven plugin provides the kar goal.

The kar goal does:

Reads all features specified in the features XML.
For each feature described in the features XML, the goal resolves the bundles described in the feature.
The goal finally packages the features XML, and the resolved bundles in a zip file.

For instance, you can use the following POM to create my-kar.kar:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>my.groupId</groupId>
    <artifactId>my-kar</artifactId>
    <version>1.0</version>
    <packaging>kar</packaging>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.karaf.tooling</groupId>
                <artifactId>karaf-maven-plugin</artifactId>
                <version>4.0.0</version>
                <extensions>true</extensions>
            </plugin>
        </plugins>
    </build>

</project>

To create the KAR file, simply type:

~$ mvn install

The kar will be installed in the target directory.

4.12.2. Commands

Apache Karaf provides kar:* commands to manage KAR archives.

`kar:list`

The kar:list command lists the installed KAR archives.

karaf@root()> kar:list
KAR Name
-------------------
my-kar-1.0-SNAPSHOT

A KAR is identified by its name.

`kar:create`

Instead of using the karaf-maven-plugin or create the KAR archive by hand, you can use the kar:create command.

The kar:create command creates a KAR file using a registered features repository.

For instance, you want to create a KAR file for the Pax Web repository.

The feature:repo-list command gives you the list of registered features repositories:

karaf@root()> feature:repo-list
Repository                       | URL
-------------------------------------------------------------------------------------------------------
standard-4.0.0                   | mvn:org.apache.karaf.features/standard/4.0.0/xml/features
enterprise-4.0.0                 | mvn:org.apache.karaf.features/enterprise/4.0.0/xml/features
spring-4.0.0                     | mvn:org.apache.karaf.features/spring/4.0.0/xml/features
org.ops4j.pax.web-4.1.4          | mvn:org.ops4j.pax.web/pax-web-features/4.1.4/xml/features

You can use one of these features repositories to create the kar file:

karaf@root()> kar:create org.ops4j.pax.web-4.1.4
Adding feature pax-jetty
Adding feature pax-http-whiteboard
Adding feature pax-war
Adding feature pax-http-tomcat
Adding feature pax-war-tomcat
Adding feature pax-http
Adding feature pax-http-jetty
Adding feature pax-jsf-support
Adding feature pax-jetty-spdy
Kar file created : /home/jbonofre/Downloads/apache-karaf-4.0.0/data/kar/org.ops4j.pax.web-4.1.4.kar

You can see that the KAR file has been created in the KARAF_DATA/kar folder.

By default, the kar:create command creates a KAR file, packaging all features in the features descriptor.

You can provide the list of features that you want to package into the KAR file:

karaf@root()> kar:create org.ops4j.pax.web-4.1.4 pax-jetty pax-tomcat
Adding feature pax-jetty
Adding feature pax-tomcat
Kar file created : /opt/apache-karaf-4.1.4/data/kar/org.ops4j.pax.web-4.1.4.kar

`kar:install`

You can deploy a KAR file using kar:install command.

The kar:install command expects the KAR URL. Any URL described in the [Artifacts repositories and URLs section|urls] is supported by the kar:install command:

karaf@root()> kar:install file:/tmp/my-kar-1.0-SNAPSHOT.kar

The KAR file is uncompressed and used to populate the KARAF_BASE/system folder.

The Apache Karaf KAR service is looking for features XML files in the KAR file, registers the features XML and automatically installs all features described in the features repositories present in the KAR file.

Optionally, you can control if the bundles should be automatically started or not using --no-start option.

`kar:uninstall`

The kar:uninstall command uninstalls a KAR file (identified by a name).

By uninstall, it means that:

the features previously installed by the KAR file are uninstalled
delete (from the KARAF_DATA/system repository) all files previously "populated" by the KAR file

For instance, to uninstall the previously installed my-kar-1.0-SNAPSHOT.kar KAR file:

karaf@root()> kar:uninstall my-kar-1.0-SNAPSHOT

4.12.3. Deployer

Apache Karaf also provides a KAR deployer. It means that you can drop a KAR file directly in the deploy folder.

Apache Karaf will automatically install KAR files from the deploy folder.

You can change the behaviours of the KAR deployer in the etc/org.apache.karaf.kar.cfg:

################################################################################
#
#    Licensed to the Apache Software Foundation (ASF) under one or more
#    contributor license agreements.  See the NOTICE file distributed with
#    this work for additional information regarding copyright ownership.
#    The ASF licenses this file to You under the Apache License, Version 2.0
#    (the "License"); you may not use this file except in compliance with
#    the License.  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#    limitations under the License.
#
################################################################################

#
# Enable or disable the refresh of the bundles when installing
# the features contained in a KAR file
#
noAutoRefreshBundles=false

#
# Enable or disable the automatic start of the bundles when installing
# the features contained in a KAR file
#
noAutoStartBundles=false

#
# Directory where the kar are stored (when downloaded from Maven for instance)
#
#karStorage=${karaf.data}/kar

By default, when the KAR deployer installs features, it refreshes the bundles already installed. You can disable the automatic bundles refresh by setting the noAutoRefreshBundles property to false.

4.12.4. JMX KarMBean

On the JMX layer, you have a MBean dedicated to the management of the KAR files.

The ObjectName to use is org.apache.karaf:type=kar,name=*.

Attributes

The Kars attributes provides the list of KAR files (name) installed.

Operations

install(url) installs the KAR file at the given url.
install(url, noAutoStartBundles) installs the KAR file at the given url, deciding if you want to automatically start the bundles or not.
create(repository, features) creates a KAR file using the given features repository name, and optionally the list of features to include in the KAR file.
uninstall(name) uninstalls a KAR file with the given name.

4.13. Instances

A instance is a complete new Apache Karaf runtime, isolated from the other ones.

The purpose is to easily create and manage a new Apache Karaf runtime without installing a complete distribution.

A instance is a new instance that you can launch separately from the root one, and deploy applications into. It means that each instance is run on a different JVM.

A instance does not contain a full copy of the Apache Karaf distribution, but only a set of the configuration files and data folder which contains all the runtime information, logs and temporary files.

4.13.1. Using the instance commands

The instance commands allow you to create and manage instances.

Creating instances

You create a new runtime instance by typing [instance:create|/commands/instance-create] in the Karaf console.

As shown in the following example, instance:create causes the runtime to create a new runtime installation in the active runtime’s `instances/[name]} directory. The new instance is a new Karaf instance and is assigned an SSH port number based on an incremental count starting at 8101 and a RMI registry port number based on an incremental count starting at 1099.

karaf@root()> instance:create test

The new instance is a fresh Apache Karaf instance. It uses the same default configuration files, as when you install a fresh Karaf distribution.

You can enable the verbose mode for the instance:create command using the -v option:

karaf@root()> instance:create -v test
Creating new instance on SSH port 8103 and registry port 1101 / RMI server port 44446 at: /opt/karaf/instances/test
Creating dir: /opt/karaf/instances/test/bin
Creating dir: /opt/karaf/instances/test/etc
Creating dir: /opt/karaf/instances/test/system
Creating dir: /opt/karaf/instances/test/deploy
Creating dir: /opt/karaf/instances/test/data
Creating file: /opt/karaf/instances/test/etc/config.properties
Creating file: /opt/karaf/instances/test/etc/jre.properties
Creating file: /opt/karaf/instances/test/etc/custom.properties
Creating file: /opt/karaf/instances/test/etc/java.util.logging.properties
Creating file: /opt/karaf/instances/test/etc/org.apache.felix.fileinstall-deploy.cfg
Creating file: /opt/karaf/instances/test/etc/org.apache.karaf.features.obr.cfg
Creating file: /opt/karaf/instances/test/etc/org.apache.karaf.features.repos.cfg
Creating file: /opt/karaf/instances/test/etc/org.apache.karaf.log.cfg
Creating file: /opt/karaf/instances/test/etc/org.ops4j.pax.logging.cfg
Creating file: /opt/karaf/instances/test/etc/org.ops4j.pax.url.mvn.cfg
Creating file: /opt/karaf/instances/test/etc/users.properties
Creating file: /opt/karaf/instances/test/etc/keys.properties
Creating file: /opt/karaf/instances/test/etc/org.apache.karaf.features.cfg
Creating file: /opt/karaf/instances/test/etc/system.properties
Creating file: /opt/karaf/instances/test/etc/org.apache.karaf.shell.cfg
Creating file: /opt/karaf/instances/test/etc/org.apache.karaf.management.cfg
Creating file: /opt/karaf/instances/test/bin/karaf
Creating file: /opt/karaf/instances/test/bin/start
Creating file: /opt/karaf/instances/test/bin/stop

You can manually configure the different ports, the location of the instance, the Apache Karaf features URLs using different options of the instance:create command. You can have details about these options using the --help option.

Cloning an instance

Instead of creating a fresh instance, you can clone an existing instance using instance:clone.

The instance:clone command reuse the files from the source instance:

karaf@root()> instance:clone root test

You can have details about the cloning options using the --help option.

Changing the instance location

By default, the new instances storage is in the KARAF_HOME/instance directory. You find a directory with the name of the instance storing the different instance files.

You can change the location of the instance using the -l option to the instance:create and instance:clone commands:

karaf@root()> instance:create -v -l /tmp/test test
Creating new instance on SSH port 8102 and registry port 1100 / RMI server port 44445 at: /tmp/test
Creating dir: /tmp/test/bin
Creating dir: /tmp/test/etc
Creating dir: /tmp/test/system
Creating dir: /tmp/test/deploy
Creating dir: /tmp/test/data
Creating file: /tmp/test/etc/config.properties
Creating file: /tmp/test/etc/jre.properties
Creating file: /tmp/test/etc/custom.properties
Creating file: /tmp/test/etc/java.util.logging.properties
Creating file: /tmp/test/etc/org.apache.felix.fileinstall-deploy.cfg
Creating file: /tmp/test/etc/org.apache.karaf.features.obr.cfg
Creating file: /tmp/test/etc/org.apache.karaf.features.repos.cfg
Creating file: /tmp/test/etc/org.apache.karaf.log.cfg
Creating file: /tmp/test/etc/org.ops4j.pax.logging.cfg
Creating file: /tmp/test/etc/org.ops4j.pax.url.mvn.cfg
Creating file: /tmp/test/etc/users.properties
Creating file: /tmp/test/etc/keys.properties
Creating file: /tmp/test/etc/org.apache.karaf.features.cfg
Creating file: /tmp/test/etc/system.properties
Creating file: /tmp/test/etc/org.apache.karaf.shell.cfg
Creating file: /tmp/test/etc/org.apache.karaf.management.cfg
Creating file: /tmp/test/bin/karaf
Creating file: /tmp/test/bin/start
Creating file: /tmp/test/bin/stop

Careful, it’s not possible to change the location of an instance once it has been created.

Note	`instance:destroy` will remove the instance location for you. You don’t have to remove the instance location "by hand".

Changing instance ports

You can change the SSH port number assigned to an instance using the instance:ssh-port-change command:

karaf@root()> instance:ssh-port-change test 8104

where test is the instance name and 8104 is the new SSH port number to use for the test instance.

You can change the RMI Registry port number (used by JMX) of an instance using the instance:rmi-registry-port-change command:

karaf@root()> instance:rmi-registry-port-change test 1102

where test is the instance name and 1102 is the new RMI Registry port number to use for the test instance.

You can also change the RMI Server port number (used by JMX too) of an instance using the instance:rmi-server-port-change command:

karaf@root()> instance:rmi-server-port-change test 44447

where test is the instance name and 44447 is the new RMI Server port number to use for the test instance.

Note	The instance has to be stopped to be able to change the port numbers.

Starting instances

New instances are created in a stopped state.

To start an instance, you can use the instance:start command:

karaf@root()> instance:start test

where test is the instance name.

Listing instances

To list the instances and their current status, you can use the instance:list command:

karaf@root()> instance:list
SSH Port | RMI Registry | RMI Server | State   | PID   | Name
-------------------------------------------------------------
    8101 |         1099 |      44444 | Started | 19652 | root
    8104 |         1101 |      44446 | Stopped | 0     | test

An instance can be in the following status:

Stopped: the instance is stopped.
Starting: the instance is starting.
Started: the instance is up and running. You can connect and use it.

Status of an instance

You can get directly the status of a given instance using the instance:status command:

karaf@root()> instance:status test
Started

where test is the instance name.

Connecting to an instance

You can connect to a running instance directly from the root one using the instance:connect command:

karaf@root()> instance:connect test

where test is the instance name where to connect to.

By default, this command will use the same username used on the root instance, and the password will be prompted.

You can use a different username using the -u or --username option. You can also provide the password using the -p or --password option.

If you don’t provide any argument, you will logon on the instance:

karaf@test()>

Note the name of instance in the shell prompt (@test).

You can logoff from the instance and return back to the root instance using the logout command or CTRL-D key binding:

karaf@test()> logout
karaf@root()>

The instance:connect command accepts shell commands as argument. It allows you to directly execute commands or scripts on the instance:

karaf@root()> instance:connect test feature:list
Name                          | Version         | Installed | Repository                | Description
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
standard                      | 4.0.0           | x         | standard-4.0.0            | Karaf standard feature
aries-annotation              | 4.0.0           |           | standard-4.0.0            | Aries Annotations
wrapper                       | 4.0.0           |           | standard-4.0.0            | Provide OS integration
service-wrapper               | 4.0.0           |           | standard-4.0.0            | Provide OS integration (alias to wrapper feature)
obr                           | 4.0.0           |           | standard-4.0.0            | Provide OSGi Bundle Repository (OBR) support
config                        | 4.0.0           | x         | standard-4.0.0            | Provide OSGi ConfigAdmin support
region                        | 4.0.0           | x         | standard-4.0.0            | Provide Region Support
...

Stop an instance

To stop an instance, you can connect to the instance (using instance:connect) and execute the system:shutdown command.

You can also use the instance:stop command:

karaf@root()> instance:stop test

where test is the instance name.

The instance will go to the "Stopped" state.

Destroy an instance

You can completely delete a stopped instance using the instance:destroy command:

karaf@root()> instance:destroy test

where test is the instance name.

Note	The `instance:destroy` deletes the instance store (the location where the instance files are stored).

Rename an instance

You can change the name of a stopped instance using the instance:rename command:

karaf@root()> instance:rename test newTest

where test is the current instance name, and newTest the new instance name.

4.13.2. Instance script

The instance:* commands require the root instance running.

But, you can also administrate directly instances without the root instance, using the bin/instance Unix script (or bin/instance.bat script on Windows).

You find the same actions that you can do with the instance:* commands in the instance[.bat] script:

bin/instance
Available commands:
  clone - Clones an existing container instance.
  create - Creates a new container instance.
  destroy - Destroys an existing container instance.
  list - Lists all existing container instances.
  opts-change - Changes the Java options of an existing container instance.
  rename - Rename an existing container instance.
  rmi-registry-port-change - Changes the RMI registry port (used by management layer) of an existing container instance.
  rmi-server-port-change - Changes the RMI server port (used by management layer) of an existing instance.
  ssh-port-change - Changes the secure shell port of an existing container instance.
  start - Start an existing container instance.
  status - Check the current status of an instance.
  stop - Stop an existing container instance.
Type 'command --help' for more help on the specified command.

For instance, to list all the instances, you can use the instance script with the list command:

bin/instance list
SSH Port | RMI Registry | RMI Server | State   | PID | Name
-----------------------------------------------------------
    8101 |         1099 |      44444 | Stopped | 0   | root
    8102 |         1100 |      44445 | Stopped | 0   | test

It’s exactly the same as executing instance:list in the root instance.

You can obtain details about commands options and arguments using the --help option. For instance:

bin/instance rename --help
DESCRIPTION
        instance:rename

        Rename an existing container instance.

SYNTAX
        instance:rename [options] name new-name

ARGUMENTS
        name
                The name of the container instance to rename
        new-name
                The new name of the container instance

OPTIONS
        --help
                Display this help message
        -v, --verbose
                Display actions performed by the command (disabled by default)

4.13.3. JMX InstanceMBean

On the JMX layer, you have a MBean dedicated to the management of the instances: the InstanceMBean.

The ObjectName to use is org.apache.karaf:type=instance,name=*.

Attributes

The Instances attribute is a tabular data attribute providing details about the instances:

Is Root (boolean): if true, the instance is the root instance, false else.
JavaOpts (string): it contains the JVM arguments used by the instance.
Location (string): it’s the path to the instance storage.
Name (string): it’s the name of the instance.
Pid (long): it’s the current system process ID (PID) of the instance process.
RMI Registry Port (int): it’s the port number of the instance RMI Registry (JMX).
RMI Server Port (int): it’s the port number of the instance RMI Server (JMX).
SSH Port (int): it’s the port number of the instance SSH Server.
State (string): it’s the current status of the instance (Stopped, Starting, Started).

Operations

The InstanceMBean provides the following operations, corresponding to the previous instance:* commands:

createInstance(instanceName, sshPort, rmiRegistryPort, rmiServerPort, location, javaOpts, features, featuresUrls): create a new instance.
changeSshPort(instanceName, port): change the SSH port of an instance.
changeRmiServerPort(instanceName, port): change the RMI server port of an instance.
changeRmiRegistry(instanceName, port): change the RMI registry port of an instance.
changeJavaOpts(instanceName, javaOpts): change the Java options of an instance.
destroyInstance(instanceName): destroy an instance.
startInstance(instanceName): start an instance.
startInstance(instanceName, options): start an instance with the given Java options.
startInstance(instanceName, options, wait, debug): start an instance with the given Java options. If wait is true, this operation is waiting for the instance is in "Started" state. If debug is true, the instance is started in debug mode.
stopInstance(instanceName): stop an instance.
renameInstance(instanceName, newInstanceName): rename an instance.
renameInstance(instanceName, newInstanceName, verbose): rename an instance. If verbose is true, this operation provides details in the log.
cloneInstance(instanceName, cloneName, sshPort, rmiRegistryPort, rmiServerPort, location, javaOpts): clone an existing instance.

4.14. Security

Apache Karaf provides an advanced and flexible security system, powered by JAAS (Java Authentication and Authorization Service) in an OSGi compliant way.

It provides a dynamic security system.

The Apache Karaf security framework is used internally to control the access to:

the OSGi services (described in the developer guide)
the console commands
the JMX layer
the WebConsole

Your applications can also use the security framework (see the developer guide for details).

Note	For security reason, by default, `karaf` user is disabled. To allow the logon, you have to have an user. You can enable `karaf` user by uncommenting the user in `etc/users.properties`: karaf = karaf,_g_:admingroup _g_\:admingroup = group,admin,manager,viewer,systembundles,ssh

4.14.1. Realms

Apache Karaf is able to manage multiple realms. A realm contains the definition of the login modules to use for the authentication and/or authorization on this realm. The login modules define the authentication and authorization for the realm.

The jaas:realm-list command lists the current defined realms:

karaf@root()> jaas:realm-list
Index | Realm Name | Login Module Class Name
-----------------------------------------------------------------------------------
1     | karaf      | org.apache.karaf.jaas.modules.properties.PropertiesLoginModule
2     | karaf      | org.apache.karaf.jaas.modules.publickey.PublickeyLoginModule

You can see that the Apache Karaf provides a default realm named karaf.

This realm has two login modules:

the PropertiesLoginModule uses the etc/users.properties file as backend for users, groups, roles and password. This login module authenticates the users and returns the users' roles.
the PublickeyLoginModule is especially used by the SSHd. It uses the etc/keys.properties file. This file contains the users and a public key associated to each user.

Apache Karaf provides additional login modules (see the developer guide for details):

JDBCLoginModule uses a database as backend
LDAPLoginModule uses a LDAP server as backend
SyncopeLoginModule uses Apache Syncope as backend
OsgiConfigLoginModule uses a configuration as backend
Krb5LoginModule uses a Kerberos Server as backend
GSSAPILdapLoginModule uses a LDAP server as backend but delegate LDAP server authentication to an other backend (typically Krb5LoginModule)

You can manage an existing realm, login module, or create your own realm using the jaas:realm-manage command.

Adding Realms or Login Modules

If a new realm should be added Apache Karaf provides an easy way to create a new Realm (although with limited flexibility compared to other approaches like blueprint or directly via DS). The jaas:realm-add command can be used for that purpose. Note, that it takes at least 2 Parameters (name of the realm and class name of the initial Login Module) or even more, if the Login Module needs parameters. For example, a new realm myrealm which uses the PropertiesLoginModule with a users file located in /tmp/users can be added by the command

jaas:realm-add myrealm org.apache.karaf.jaas.modules.properties.PropertiesLoginModule users "/tmp/users"

To add a new Login Module to an existing realm the jaas:module-add command can be used. It is similar in semantics than the jaas:realm-add command except that it takes no realm name. Instead, the realm to modify has to be selected via jaas:realm-manage previously. Note that the options for the Login Module are given as a list of parameters which is interpreted as a map in the order "key1 value1 key2 value2". So the command

jaas:module-add org.apache.karaf.jaas.modules.properties.PropertiesLoginModule users "/tmp/users"

will add a PropertiesLoginModule with parameters map users -> /tmp/users to the selected realm.

4.14.2. Users, groups, roles, and passwords

As we saw, by default, Apache Karaf uses a PropertiesLoginModule.

This login module uses the etc/users.properties file as storage for the users, groups, roles and passwords.

The initial etc/users.properties file contains:

################################################################################
#
#    Licensed to the Apache Software Foundation (ASF) under one or more
#    contributor license agreements.  See the NOTICE file distributed with
#    this work for additional information regarding copyright ownership.
#    The ASF licenses this file to You under the Apache License, Version 2.0
#    (the "License"); you may not use this file except in compliance with
#    the License.  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#    limitations under the License.
#
################################################################################

#
# This file contains the users, groups, and roles.
# Each line has to be of the format:
#
# USER=PASSWORD,ROLE1,ROLE2,...
# USER=PASSWORD,_g_:GROUP,...
# _g_\:GROUP=ROLE1,ROLE2,...
#
# All users, grousp, and roles entered in this file are available after Karaf startup
# and modifiable via the JAAS command group. These users reside in a JAAS domain
# with the name "karaf".
#
karaf = karaf,_g_:admingroup
_g_\:admingroup = group,admin,manager,viewer,ssh

We can see in this file, that we have one user by default: karaf. The default password is karaf.

The karaf user is member of one group: the admingroup.

A group is always prefixed by _g_:. An entry without this prefix is a user.

A group defines a set of roles. By default, the admingroup defines group, admin, manager, and viewer roles.

It means that the karaf user will have the roles defined by the admingroup.

Commands

The jaas:* commands manage the realms, users, groups, roles in the console.

`jaas:realm-list`

We already used the jaas:realm-list previously in this section.

The jaas:realm-list command lists the realm and the login modules for each realm:

karaf@root()> jaas:realm-list
Index | Realm Name | Login Module Class Name
-----------------------------------------------------------------------------------
1     | karaf      | org.apache.karaf.jaas.modules.properties.PropertiesLoginModule
2     | karaf      | org.apache.karaf.jaas.modules.publickey.PublickeyLoginModule

We have here one realm (karaf) containing two login modules (PropertiesLoginModule and PublickeyLoginModule).

The index is used by the jaas:realm-manage command to easily identify the realm/login module that we want to manage.

`jaas:realm-manage`

The jaas:realm-manage command switch in realm/login module edit mode, where you can manage the users, groups, and roles in the login module.

To identify the realm and login module that you want to manage, you can use the --index option. The indexes are displayed by the jaas:realm-list command:

karaf@root()> jaas:realm-manage --index 1

Another way is to use the --realm and --module options. The --realm option expects the realm name, and the --module option expects the login module class name:

karaf@root()> jaas:realm-manage --realm karaf --module org.apache.karaf.jaas.modules.properties.PropertiesLoginModule

`jaas:user-list`

When you are in edit mode, you can list the users in the login module using the jaas:user-list:

karaf@root()> jaas:user-list
User Name | Group      | Role
--------------------------------
karaf     | admingroup | admin
karaf     | admingroup | manager
karaf     | admingroup | viewer

You can see the user name and the group by role.

`jaas:user-add`

The jaas:user-add command adds a new user (and the password) in the currently edited login module:

karaf@root()> jaas:user-add foo bar

To "commit" your change (here the user addition), you have to execute the jaas:update command:

karaf@root()> jaas:update
karaf@root()> jaas:realm-manage --index 1
karaf@root()> jaas:user-list
User Name | Group      | Role
--------------------------------
karaf     | admingroup | admin
karaf     | admingroup | manager
karaf     | admingroup | viewer
foo       |            |

On the other hand, if you want to rollback the user addition, you can use the jaas:cancel command.

`jaas:user-delete`

The jaas:user-delete command deletes a user from the currently edited login module:

karaf@root()> jaas:user-delete foo

Like for the jaas:user-add command, you have to use the jaas:update to commit your change (or jaas:cancel to rollback):

karaf@root()> jaas:update
karaf@root()> jaas:realm-manage --index 1
karaf@root()> jaas:user-list
User Name | Group      | Role
--------------------------------
karaf     | admingroup | admin
karaf     | admingroup | manager
karaf     | admingroup | viewer

`jaas:group-add`

The jaas:group-add command assigns a group (and eventually creates the group) to a user in the currently edited login module:

karaf@root()> jaas:group-add karaf mygroup

`jaas:group-delete`

The jaas:group-delete command removes a user from a group in the currently edited login module:

karaf@root()> jaas:group-delete karaf mygroup

`jaas:group-role-add`

The jaas:group-role-add command adds a role in a group in the currently edited login module:

karaf@root()> jaas:group-role-add mygroup myrole

`jaas:group-role-delete`

The jaas:group-role-delete command removes a role from a group in the currently edited login module:

karaf@root()> jaas:group-role-delete mygroup myrole

`jaas:update`

The jaas:update command commits your changes in the login module backend. For instance, in the case of the PropertiesLoginModule, the etc/users.properties will be updated only after the execution of the jaas:update command.

`jaas:cancel`

The jaas:cancel command rollback your changes and doesn’t update the login module backend.

4.14.3. Passwords encryption

By default, the passwords are stored in clear form in the etc/users.properties file.

It’s possible to enable encryption in the etc/org.apache.karaf.jaas.cfg configuration file:

################################################################################
#
#    Licensed to the Apache Software Foundation (ASF) under one or more
#    contributor license agreements.  See the NOTICE file distributed with
#    this work for additional information regarding copyright ownership.
#    The ASF licenses this file to You under the Apache License, Version 2.0
#    (the "License"); you may not use this file except in compliance with
#    the License.  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#    limitations under the License.
#
################################################################################

#
# Boolean enabling / disabling encrypted passwords
#
encryption.enabled = false

#
# Encryption Service name
#   basic: the default encryption service which digests passwords without
#          salting them
#   jasypt: a more powerful alternative which supports salting
#   spring-security-crypto: Supports bcrypt, argon2, pbkdf2, scrypt. Requires
#                           the "spring-security-crypto-encryption" feature
#                           to be installed.
#
encryption.name = basic

#
# Encryption prefix
#
encryption.prefix = {CRYPT}

#
# Encryption suffix
#
encryption.suffix = {CRYPT}

#
# Set the encryption algorithm to use in Karaf JAAS login module
# Supported encryption algorithms follow:
#   basic/jasypt: MD2, MD5, SHA-1, SHA-256, SHA-384, SHA-512
#   spring-security-crypto: argon2, bcrypt, pbkdf2, scrypt
#
encryption.algorithm = SHA-256

#
# Encoding of the encrypted password.
# Can be:
#   hexadecimal
#   base64
#
encryption.encoding = hexadecimal

If the encryption.enabled property is set to true, the password encryption is enabled.

With encryption enabled, the password are encrypted at the first time a user logs in. The encrypted passwords are prefixed and suffixed with \{CRYPT\}. To re-encrypt the password, you can reset the password in clear (in etc/users.properties file), without the \{CRYPT\} prefix and suffix. Apache Karaf will detect that this password is in clear (because it’s not prefixed and suffixed with \{CRYPT\}) and encrypt it again.

The encryption.name property defines which encryption provider is used. The default is "basic" which just supports basic digesting of the password, without salting. This is not secure for production environments. A more secure alternative is "jasypt", which supports digesting with salting. However, the most secure alternative which should be used in production is "spring-security-crypto", which supports modern password digest algorithms such as "argon2" and "bcrypt".

The etc/org.apache.karaf.jaas.cfg configuration file allows you to define advanced encryption behaviours:

the encryption.prefix property defines the prefix to "flag" a password as encrypted. The default is \{CRYPT\}.
the encryption.suffix property defines the suffix to "flag" a password as encrypted. The default is \{CRYPT\}.
the encryption.algorithm property defines the algorithm to use for encryption (digest). The possible values for the "basic" and "jasypt" provides are: MD2, MD5, SHA-1, SHA-256, SHA-384, SHA-512. The default is SHA-256 since Karaf 4.3.0, prior to this it was MD5. When the "spring-security-crypto" encryption.name is configured, the possible values are: argon2, bcrypt, pbkdf2, scrypt.
the encryption.encoding property defines the encoding of the encrypted password. The possible values are hexadecimal or base64. The default value is hexadecimal.

4.14.4. Managing authentication by key

For the SSH layer, Karaf supports the authentication by key, allowing to login without providing the password.

The SSH client (so bin/client provided by Karaf itself, or any ssh client like OpenSSH) uses a public/private keypair that will identify itself on Karaf SSHD (server side).

The keys allowed to connect are stored in etc/keys.properties file, following the format:

user=key,role

The easiest way to create key pair is to use OpenSSH.

You can create a key pair using:

ssh-keygen -t rsa -f karaf.id_rsa

NB: you can provide a passphrase with -N option to ssh-keygen but, in that case, you will need to enter the passphrase to allow the SSH client to use the key.

You have now the public and private keys:

-rw-------  1 jbonofre jbonofre    771 Jul 25 22:05 karaf.id_rsa
-rw-r--r--  1 jbonofre jbonofre    607 Jul 25 22:05 karaf.id_rsa.pub

You copy the key from karaf.id_rsa.pub file in the etc/keys.properties:

karaf=AAAAB3NzaC1yc2EAAAADAQABAAABAQCtXN9ZZ+K67UFbxZMxHsoR69vHNbN8qi17v/5jF83FUexRqu8FvWCInBoW7eVFyeIiFXGd/zaCrDHrZsqpwXNEha3ifvfGTY2+gMLfZZFgh2LFubXBH6G725XKs9aus+KLrwC8u/uPr9Sw3YeSb0zxrjiXqv6hGYhaAHnskAgRCUxa+P4/JYNVS/2+ZrvBrVMAwgEuwt1Y1IDYsXQRmLJPn5ayMCfzPTANXfgB7Hix    72f2XpHV3FdnKTbYwdA32Bg4ptJkuvyMXnBy5y7ChRU150YGRToC4ETcPF2DB0EPOcbOLsQlNTKKRYuNR1zEpp6RAfiWD65kmYK766CE8AbB,_g_:admingroup
_g_\:admingroup = group,admin,manager,viewer,systembundles,ssh

and specify to the client to use the karaf.id_rsa private key:

bin/client -k ~/karaf.id_rsa

or to ssh

ssh -p 8101 -i ~/karaf.id_rsa karaf@localhost

4.14.5. RBAC

Apache Karaf uses the roles to control the access to the resources: it’s a RBAC (Role Based Access Control) system.

The roles are used to control:

access to OSGi services
access to the console (control the execution of the commands)
access to JMX (MBeans and/or operations)
access to the WebConsole

OSGi services

The details about OSGi services RBAC support is explained in the developer guide.

Console

Console RBAC supports is a specialization of the OSGi service RBAC. Actually, in Apache Karaf, all console commands are defined as OSGi services.

The console command name follows the scope:name format.

The ACL (Access Lists) are defined in etc/org.apache.karaf.command.acl.<scope>.cfg configuration files, where <scope> is the commands scope.

For instance, we can define the ACL to the feature:* commands by creating a etc/org.apache.karaf.command.acl.feature.cfg configuration file. In this etc/org.apache.karaf.command.acl.feature.cfg configuration file, we can set:

list = viewer
info = viewer
install = admin
uninstall = admin

Here, we define that feature:list and feature:info commands can be executed by users with viewer role, whereas the feature:install and feature:uninstall commands can only be executed by users with admin role. Note that users in the admin group will also have viewer role, so will be able to do everything.

Apache Karaf command ACLs can control access using (inside a given command scope):

the command name regex (e.g. name = role)
the command name and options or arguments values regex (e.g. name[/.*[0-9][0-9][0-9]+.*/] = role to execute name only with argument value above 100)

Both command name and options/arguments support exact matching or regex matching.

By default, Apache Karaf defines the following commands ACLs:

etc/org.apache.karaf.command.acl.bundle.cfg configuration file defines the ACL for bundle:* commands. This ACL limits the execution of bundle:* commands for system bundles only to the users with admin role, whereas bundle:* commands for non-system bundles can be executed by the users with manager role.
etc/org.apache.karaf.command.acl.config.cfg configuration file defines the ACL for config:* commands. This ACL limits the execution of config:* commands with jmx.acl.*, org.apache.karaf.command.acl.*, and org.apache.karaf.service.acl.* configuration PID to the users with admin role. For the other configuration PID, the users with the manager role can execute config:* commands.
etc/org.apache.karaf.command.acl.feature.cfg configuration file defines the ACL for feature:* commands. Only the users with admin role can execute feature:install, feature:uninstall,feature:start, feature:stop and feature:update commands. The other feature:* commands can be executed by any user.
etc/org.apache.karaf.command.acl.jaas.cfg configuration file defines the ACL for jaas:* commands. Only the users with admin role can execute jaas:update command. The other jaas:* commands can be executed by any user.
etc/org.apache.karaf.command.acl.kar.cfg configuration file defines the ACL for kar:* commands. Only the users with admin role can execute kar:install and kar:uninstall commands. The other kar:* commands can be executed by any user.
etc/org.apache.karaf.command.acl.shell.cfg configuration file defines the ACL for shell:* and "direct" commands. Only the users with admin role can execute shell:edit, shell:exec, shell:new, and shell:java commands. The other shell:* commands can be executed by any user.
etc/org.apache.karaf.command.acl.system.cfg configuration file defines the ACL for system:* commands. Only the users with admin role can execute system:property and system:shutdown commands. Users with manager role can call system:start-level above 100, otherwise admin role is required. Also users with viewer role can obtain the current start-level. The other system:* commands can be executed by any user.

You can change these default ACLs, and add your own ACLs for additional command scopes (for instance etc/org.apache.karaf.command.acl.cluster.cfg for Apache Karaf Cellar, etc/org.apache.karaf.command.acl.camel.cfg from Apache Camel, …).

You can fine tune the command RBAC support by editing the karaf.secured.services property in etc/system.properties:

#
# By default, only Karaf shell commands are secured, but additional services can be
# secured by expanding this filter
#
karaf.secured.services = (&(osgi.command.scope=*)(osgi.command.function=*))

JMX

Like for the console commands, you can define ACL (AccessLists) to the JMX layer.

The JMX ACL are defined in etc/jmx.acl<ObjectName>.cfg configuration file, where <ObjectName> is a MBean object name (for instance org.apache.karaf.bundle represents org.apache.karaf;type=Bundle MBean).

The etc/jmx.acl.cfg is the most generic configuration file and is used when no specific ones are found. It contains the "global" ACL definition.

JMX ACLs can control access using (inside a JMX MBean):

the operation name regex (e.g. operation* = role)
the operation arguments value regex (e.g. operation(java.lang.String, int)[/([1-4])?[0-9]/,/.*/] = role)

By default, Apache Karaf defines the following JMX ACLs:

etc/jmx.acl.org.apache.karaf.bundle.cfg configuration file defines the ACL for the org.apache.karaf:type=bundle MBean. This ACL limits the setStartLevel(), start(), stop(), and update() operations for system bundles for only users with admin role. The other operations can be performed by users with the manager role.
etc/jmx.acl.org.apache.karaf.config.cfg configuration file defines the ACL for the org.apache.karaf:type=config MBean. This ACL limits the change on jmx.acl*, org.apache.karaf.command.acl*, and org.apache.karaf.service.acl* configuration PIDs for only users with admin role. The other operations can be performed by users with the manager role.
etc/jmx.acl.org.apache.karaf.security.jmx.cfg configuration file defines the ACL for the org.apache.karaf:type=security,area=jmx MBean. This ACL limits the invocation of the canInvoke() operation for the users with viewer role.
etc/jmx.acl.osgi.compendium.cm.cfg configuration file defines the ACL for the osgi.compendium:type=cm MBean. This ACL limits the changes on jmx.acl*, org.apache.karaf.command.acl*, and org.apache.karaf.service.acl* configuration PIDs for only users with admin role. The other operations can be performed by users with the manager role.
etc/jmx.acl.java.lang.Memory.cfg configuration file defines the ACL for the core JVM Memory MBean. This ACL limits the invocation of the gc operation for only users with the manager role.
etc/jmx.acl.cfg configuration file is the most generic file. The ACLs defined here are used when no other specific ACLs match (by specific ACL, it’s an ACL defined in another MBean specific etc/jmx.acl.*.cfg configuration file). The list*(), get*(), is*() operations can be performed by users with the viewer role. The set*() and all other *() operations can be performed by users with the admin role.

WebConsole

The Apache Karaf WebConsole is not available by default. To enable it, you have to install the webconsole feature:

karaf@root()> feature:install webconsole

The WebConsole doesn’t support fine grained RBAC like console or JMX for now.

All users with the admin role can logon to the WebConsole and perform any operations.

4.14.6. SecurityMBean

Apache Karaf provides a JMX MBean to check if the current user can invoke a given MBean and/or operation.

The canInvoke() operation gets the roles of the current user, and check if one the roles can invoke the MBean and/or the operation, eventually with a given argument value.

Operations

canInvoke(objectName) returns true if the current user can invoke the MBean with the objectName, false else.
canInvoke(objectName, methodName) returns true if the current user can invoke the operation methodName on the MBean with the objectName, false else.
canInvoke(objectName, methodName, argumentTypes) returns true if the current user can invoke the operation methodName with the array of arguments types argumentTypes on the MBean with objectName, false else.
canInvoke(bulkQuery) returns a tabular data containing for each operation in the bulkQuery tabular data if canInvoke is true or false.

4.14.7. Security providers

Some applications require specific security providers to be available, such as [BouncyCastle|http://www.bouncycastle.org].

The JVM imposes some restrictions about the use of such jars: they have to be signed and be available on the boot classpath.

One way to deploy those providers is to put them in the JRE folder at $JAVA_HOME/jre/lib/ext and modify the security policy configuration ($JAVA_HOME/jre/lib/security/java.security) in order to register such providers.

While this approach works fine, it has a global effect and requires you to configure all your servers accordingly.

Apache Karaf offers a simple way to configure additional security providers:

put your provider jar in lib/ext
modify the etc/config.properties configuration file to add the following property

org.apache.karaf.security.providers = xxx,yyy

The value of this property is a comma separated list of the provider class names to register.

For instance, to add the bouncycastle security provider, you define:

org.apache.karaf.security.providers = org.bouncycastle.jce.provider.BouncyCastleProvider

In addition, you may want to provide access to the classes from those providers from the system bundle so that all bundles can access those.

It can be done by modifying the org.osgi.framework.bootdelegation property in the same configuration file:

org.osgi.framework.bootdelegation = ...,org.bouncycastle*

4.15. Docker

Apache Karaf provides Docker resources allowing you to easily create your own image and container.

Official Karaf docker image are also available on Docker Hub.

But, Apache Karaf also provides a docker feature that allows you to:

manipulate Docker containers directly from Apache Karaf
create a Docker container based on the current running Apache Karaf instance (named provisioning)

4.15.1. Docker images

You can find the docker resource at https://github.com/apache/karaf/tree/master/assemblies/docker.

As prerequisites, you have:

to install the most recent stable version of docker (https://docs.docker.com/installation/)
to install the most recent stable version of docker-compose (https://docs.docker.com/compose/install/)

Official images

The Apache Karaf official images are available on Docker HUB: https://hub.docker.com/r/apache/karaf/tags?page=1&ordering=last_updated

You can directly pull the official image:

docker pull apache/karaf

Build your own

You can create your own docker image. The images are based on the official Java Alpine (OpenJDK 8) image. If you want to build the Karaf image run:

sh build.sh

docker build -t karaf .

If you want to build the container for a specific version of Karaf you can configure it with the KARAF_VERSION arg:

docker build --build-arg KARAF_VERSION=4.2.0 -t "karaf:4.2.0" karaf

Run

Run Karaf in interactive mode (using Karaf official docker image):

docker run -i -t --name karaf apache/karaf:latest karaf

Run Karaf without interaction but log displayed (using Karaf official docker image):

docker run --name karaf apache/karaf:latest

Kill Karaf

docker kill karaf

Ports

The Karaf SSH server is on 8101
The Karaf WebContainer is on 8888
The Karaf JMX MBean server is on 1099 (default, not exposed to host) and 44444 (default, not exposed to host)

Edit the docker-compose.yml file to edit port settings.

4.15.2. Docker feature

Docker is an optional feature from the Karaf Enterprise features repository.

It means that you have to install the docker feature first:

karaf@root()> feature:install docker

The Karaf Docker feature uses the Docker HTTP layer to communicate with the Docker backend. It could be on the same local machine where Apache Karaf instance is running or a remote Docker machine.

The location of the Docker backend (URL) can be specified as an option to the docker:* commands. By default, Karaf Docker feature uses http://localhost:2375. Please, take a look on the Docker documentation how to enable remote API using HTTP for Docker daemon. In a nutshell, you just have to enable the tcp transport connector for the docker daemon. You have to do it using the -H option on dockerd:

/usr/bin/dockerd -H fd:// -H tcp://localhost:2375

Apache Karaf Docker feature exposes DockerService OSGi service that you can use programmatically (the docker:* commands and the DockerMBean use the DockerService service).

4.15.3. System-wide information

The docker:info command provides some details about the docker backend:

karaf@root()> docker:info
Containers: 0
Debug: false
Driver: overlay2
ExecutionDriver: null
IPv4Forwarding: true
Images: 1
IndexServerAddress: https://index.docker.io/v1/
InitPath: null
InitSha1: null
KernelVersion: 4.15.0-29-generic
MemoryLimit: true
NEventsListener: false
NFd: 20
NGoroutines: 34
SwapLimit: false

4.15.4. Show the Docker version information

The docker:version command provides details about the docker version:

karaf@root()> docker:version
Version: 17.12.1-ce
Os: linux
Kernel version: 4.15.0-29-generic
Go version: go1.10.1
Git commit: 7390fc6
Arch: amd64
API version: 1.35
Build time: 2018-02-28T17:46:05.000000000+00:00
Experimental: null

4.15.5. Search image

The docker:search command (or search() operation on the DockerMBean) searches for a image on Docker HUB:

karaf@root()> docker:search java
Name                                       │ Description                                                                                          │ Automated │ Official │ Star Count
───────────────────────────────────────────┼──────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────┼──────────┼───────────
java                                       │ Java is a concurrent, class-based, and object-oriented programming language.                         │ false     │ true     │ 1774
anapsix/alpine-java                        │ Oracle Java 8 (and 7) with GLIBC 2.23 over AlpineLinux                                               │ true      │ false    │ 332
node                                       │ Node.js is a JavaScript-based platform for server-side and networking applications.                  │ false     │ true     │ 5893
tomcat                                     │ Apache Tomcat is an open source implementation of the Java Servlet and JavaServer Pages technologies │ false     │ true     │ 1950
openjdk                                    │ OpenJDK is an open-source implementation of the Java Platform, Standard Edition                      │ false     │ true     │ 1097
frekele/java                               │ docker run --rm --name java frekele/java                                                             │ true      │ false    │ 10
ghost                                      │ Ghost is a free and open source blogging platform written in JavaScript                              │ false     │ true     │ 799
appuio/s2i-maven-java                      │ S2I Builder with Maven and Java                                                                      │ true      │ false    │ 1
zabbix/zabbix-java-gateway                 │ Zabbix Java Gateway                                                                                  │ true      │ false    │ 13
jetty                                      │ Jetty provides a Web server and javax.servlet container.                                             │ false     │ true     │ 260
fabric8/s2i-java                           │ S2I Builder Image for plain Java applications                                                        │ false     │ false    │ 5
appuio/s2i-gradle-java                     │ S2I Builder with Gradle and Java                                                                     │ true      │ false    │ 1
cloudbees/jnlp-slave-with-java-build-tools │ Extends cloudbees/java-build-tools docker image to make it a JNLP slave                              │ true      │ false    │ 18
blacklabelops/java                         │ Java Base Images.                                                                                    │ true      │ false    │ 8
groovy                                     │ Apache Groovy is a multi-faceted language for the Java platform.                                     │ false     │ true     │ 47
lwieske/java-8                             │ Oracle Java 8 Container - Full + Slim - Based off Alpine + CentOS (8u00 - 8u172)                     │ true      │ false    │ 39
davidcaste/alpine-java-unlimited-jce       │ Oracle Java 8 (and 7) with GLIBC 2.21 over AlpineLinux with unlimited JCE patch applied              │ true      │ false    │ 11
cfje/java-test-applications                │ Java Test Applications CI Image                                                                      │ false     │ false    │ 0
thingswise/java-docker                     │ Java + dcd                                                                                           │ true      │ false    │ 0
rightctrl/java                             │ Oracle Java                                                                                          │ true      │ false    │ 2
cfje/java-resource                         │ Java Concourse Resource                                                                              │ false     │ false    │ 0
cfje/java-buildpack                        │ Java Buildpack CI Image                                                                              │ false     │ false    │ 0
tomee                                      │ Apache TomEE is an all-Apache Java EE certified stack where Apache Tomcat is top dog.                │ false     │ true     │ 53
couchdb                                    │ CouchDB is a database that uses JSON for documents, an HTTP API, & JavaScript/declarative indexing.  │ false     │ true     │ 218
dwolla/java                                │ Dwolla’s custom Java image                                                                           │ true      │ false    │ 1

4.15.6. Pull image

The docker:pull command (or pull() operation on the DockerMBean) pull a image from Docker HUB:

karaf@root()> docker:pull -v java:8-jre-alpine
{"status":"Pulling from library/java","id":"latest"}
{"status":"Pulling fs layer","progressDetail":{},"id":"5040bd298390"}
{"status":"Pulling fs layer","progressDetail":{},"id":"fce5728aad85"}
{"status":"Pulling fs layer","progressDetail":{},"id":"76610ec20bf5"}
{"status":"Pulling fs layer","progressDetail":{},"id":"60170fec2151"}
{"status":"Pulling fs layer","progressDetail":{},"id":"e98f73de8f0d"}
{"status":"Pulling fs layer","progressDetail":{},"id":"11f7af24ed9c"}
{"status":"Pulling fs layer","progressDetail":{},"id":"49e2d6393f32"}
{"status":"Pulling fs layer","progressDetail":{},"id":"bb9cdec9c7f3"}
{"status":"Waiting","progressDetail":{},"id":"11f7af24ed9c"}
{"status":"Waiting","progressDetail":{},"id":"49e2d6393f32"}
{"status":"Waiting","progressDetail":{},"id":"bb9cdec9c7f3"}
{"status":"Waiting","progressDetail":{},"id":"60170fec2151"}
{"status":"Waiting","progressDetail":{},"id":"e98f73de8f0d"}

4.15.7. Listing images

The docker:images command (or images() operation on the DockerMBean) lists the available images on docker:

karaf@root()> docker:images
Id                                                                      │ RepoTags            │ Created    │ Labels │ Size      │ Virtual Size
────────────────────────────────────────────────────────────────────────┼─────────────────────┼────────────┼────────┼───────────┼─────────────
sha256:fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7 │ [java:8-jre-alpine] │ 1488578492 │ {}     │ 107854045 │ 107854045
sha256:d23bdf5b1b1b1afce5f1d0fd33e7ed8afbc084b594b9ccf742a5b27080d8a4a8 │ [java:latest]       │ 1484614374 │ {}     │ 643195347 │ 643195347

4.15.8. Remove image

The docker:rmi command (or rmi() operation on the DockerMBean) removes an image from docker:

karaf@root()> docker:rmi --force sha256:d23bdf5b1b1b1afce5f1d0fd33e7ed8afbc084b594b9ccf742a5b27080d8a4a8

4.15.9. Image history

The docker:history command displays the complete history for a given image:

karaf@root()> docker:history sha256:fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7
ID                                                                      │ Created    │ Created By                                                                                                                                                                                                                 │ Tags │ Size
────────────────────────────────────────────────────────────────────────┼────────────┼────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼──────┼────────────────────
sha256:fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7 │ 1488578492 │ /bin/sh -c set -x        && apk add --no-cache           openjdk8-jre="$JAVA_ALPINE_VERSION"     && [ "$JAVA_HOME" = "$(docker-java-home)" ]                                                                                                │      │ [java:8-jre-alpine]
<missing>                                                               │ 1488578488 │ /bin/sh -c #(nop)  ENV JAVA_ALPINE_VERSION=8.111.14-r0                                                                                                                                                                     │      │
<missing>                                                               │ 1488578488 │ /bin/sh -c #(nop)  ENV JAVA_VERSION=8u111                                                                                                                                                                                  │      │
<missing>                                                               │ 1488578487 │ /bin/sh -c #(nop)  ENV PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/lib/jvm/java-1.8-openjdk/jre/bin:/usr/lib/jvm/java-1.8-openjdk/bin                                                           │      │
<missing>                                                               │ 1488578487 │ /bin/sh -c #(nop)  ENV JAVA_HOME=/usr/lib/jvm/java-1.8-openjdk/jre                                                                                                                                                         │      │
<missing>                                                               │ 1488578458 │ /bin/sh -c {             echo '#!/bin/sh';               echo 'set -e';          echo;           echo 'dirname "$(dirname "$(readlink -f "$(which javac || which java)")")"';    } > /usr/local/bin/docker-java-home       && chmod +x /usr/local/bin/docker-java-home │      │
<missing>                                                               │ 1488578457 │ /bin/sh -c #(nop)  ENV LANG=C.UTF-8                                                                                                                                                                                        │      │
<missing>                                                               │ 1488573141 │ /bin/sh -c #(nop) ADD file:3df55c321c1c8d73f22bc69240c0764290d6cb293da46ba8f94ed25473fb5853 in /                                                                                                                           │      │

4.15.10. Pushing and tagging image

The docker:push command allows you to push an image on a given repository.

The docker:tag command create a new tag for a given image.

4.15.11. Create container

The Karaf Docker feature can create a Docker container based on a given image.

You can use either the docker:create shell command or the create() operation on the JMX DockerMBean.

For instance, here’s an example of the docker:bootstrap to create a Docker container based on elasticsearch instance:

karaf@root()> docker:create --image fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7 --cmd /bin/bash test

4.15.12. Listing containers

You can list the containers:

karaf@root()> docker:ps -a
Id                                                               │ Names   │ Command   │ Created    │ Image                                                            │ Image ID                                                                │ Status  │ State   │ Ports │ Size │ Size Root
─────────────────────────────────────────────────────────────────┼─────────┼───────────┼────────────┼──────────────────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┼─────────┼─────────┼───────┼──────┼──────────
92f8b280a7fa69c9ff673ed9678b7040a56c16c9c4aa403498a538cf0f501e9e │ [/test] │ /bin/bash │ 1532809485 │ fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7 │ sha256:fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7 │ Created │ created │       │ 0    │ 0

You can also use the containers attribute on the DockerMBean JMX MBean or the containers() method on the DockerService service.

4.15.13. Provision Docker container

Provisioning is a specific way of creating a container based on the current running Karaf instance: it creates a Docker container using the current running Apache Karaf instance karaf.base.

You can then reuse this container to create a Docker image and to duplicate the container on another Docker backend via dockerhub.

karaf@root()> docker:provision my-karaf

You can also use the provision() method on the DockerMBean JMX MBean or the DockerService service.

4.15.14. Start container

You can start a container using the docker:start command:

karaf@root()> docker:start my-container

You can also use the start() method on the DockerMBean JMX MBean or the DockerService service.

4.15.15. Stop container

You can stop a container using the docker:stop command:

karaf@root()> docker:stop my-container

You can also use the stop() method on the DockerMBean JMX MBean or the DockerService service.

4.15.16. Restart container

You can restart a container using the docker:restart command:

karaf@root()> docker:restart my-container

4.15.17. Delete container

You can delete an existing Docker container using the docker:rm commmand:

karaf@root()> docker:rm my-container

You can also use the rm() method on the DockerMBean JMX MBean or the DockerService service.

4.15.18. Pause container

The docker:pause command pauses all processes within one or more containers:

karaf@root()> docker:pause my-container

4.15.19. Unpause container

The docker:unpause command unpauses all processes within one or more containers:

karaf@root()> docker:unpause my-container

4.15.20. Kill container

The docker:kill command kills a running container:

karaf@root()> docker:kill my-container

4.15.21. Rename container

The docker:rename command renames an existing container:

karaf@root()> docker:rename my-container new-container

4.15.22. Logs

The docker:logs command displays the log on an existing container:

karaf@root()> docker:logs --timestamps --details --stdout --stderr my-container

4.15.23. Top

The docker:top command displays the current running processes in an existing container:

karaf@root()> docker:top my-container

4.16. OBR

The goal of OBR (OSGi Bundle Repository) is:

to simplify deploying and using bundles
to encourage independent bundle development.

OBR achieves the first goal by providing a service that can automatically install a bundle, with its deployment dependencies, from a bundle repository. This makes it easier for people to experiment with existing bundles.

The second goal is achieved by raising the visibility of the available bundles in a repository.

OBR is an optional Apache Karaf feature. You have to install the obr feature to use OBR service:

karaf@root()> feature:install obr

The OBR feature turns Apache Karaf into an OBR client. It means that Apache Karaf can use a OBR repository for the installation of the bundles, and during the installation of the features.

The installation of the obr feature adds in Apache Karaf:

the OBR service
the features OBR resolver
the obr:* commands
the JMX ObrMBean

The OBR repository contains all bundles. The OBR service knows all requirements and capabilities of each bundle on an OBR repository (it’s the OBR metadata).

Thanks to that, when you install ("deploy" in OBR wording) a bundle using the OBR service, it looks for all bundles providing the capabilities matching the bundle requirements. It will automatically install the bundles needed for the bundle.

4.16.1. Features OBR resolver

If the feature specifies obr in the resolver attribute, Apache Karaf can use the OBR service to construct the list of bundles to install with the features.

The feature default resolver just consider the bundles described in the feature itself.

Using the OBR resolver, Apache Karaf can extend the bundle list at the feature installation time using the OBR service.

4.16.2. Commands

`obr:url-add`

The obr:url-add command registers the OBR repository at a given URL in the OBR service.

Basically, an OBR repository is described by a repository.xml file.

The obr:url-add command expects an url argument. The url argument is the URL to the OBR repository repository.xml file. Any URL described in the [Artifacts repositories and URLs section|urls] is supported.

For instance:

karaf@root()> obr:url-add file:///user/.m2/repository/repository.xml

`obr:url-list`

The obr:url-list command lists the OBR repository (with URL) registered in the OBR service:

karaf@root()> obr:url-list
Index | OBR URL
---------------------------------------------------------
0     | file:/user/.m2/repository/repository.xml

`obr:url-refresh`

The obr:url-refresh command refreshes an OBR repository (reloading the URL).

The OBR service doesn’t take "on the fly" the changes performed on an OBR repository repository.xml. You have to reload the repository.xml URL to take the changes. It’s the purpose of the obr:url-refresh command.

Without argument, the obr:url-refresh command refreshes all repositories:

karaf@root()> obr:url-refresh

You can refresh only one repository by specifying the URL as argument:

karaf@root()> obr:url-refresh file:/user/.m2/repository/repository.xml

Instead of using the URL, you can use the repository index as displayed by the obr:url-list command. To do so, you have to use the -i option:

karaf@root()> obr:url-refresh -i 0

`obr:url-remove`

The obr:url-remove command removes an OBR repository from the OBR service.

The obr:url-remove command expects the repository URL as argument:

karaf@root()> obr:url-remove file:/user/.m2/repository/repository.xml

Instead of using the URL, you can use the repository index as displayed by the obr:url-list command. To do so, you have to use the -i option:

karaf@root()> obr:url-remove -i 0

`obr:list`

The obr:list command lists all bundles available on the registered OBR repositories:

karaf@root()> obr:list|more
Name                                                                         | Symbolic Name                                                             | Version
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
activemq-blueprint                                                           | org.apache.activemq.activemq-blueprint                                    | 5.12.0.SNAPSHOT
activemq-camel                                                               | org.apache.activemq.activemq-camel                                        | 5.12.0.SNAPSHOT
activemq-karaf                                                               | activemq-karaf                                                            | 5.12.0.SNAPSHOT
activemq-osgi                                                                | org.apache.activemq.activemq-osgi                                         | 5.12.0.SNAPSHOT
Apache Aries Application API                                                 | org.apache.aries.application.api                                          | 1.0.1.SNAPSHOT
...

`obr:info`

The obr:info command displays the details about bundles available on the OBR service. Especially, it provides details about capabilities and requirements of bundles.

The obr:info command expects a bundle symbolic name as argument:

karaf@root()> obr:info org.apache.karaf.wrapper.core
-------------------------------
Apache Karaf :: Wrapper :: Core
-------------------------------
id: org.apache.karaf.wrapper.core/4.0.0
description: Core implementation and integration of the Java Service Wrapper.        It provides a complete integration of Karaf with your Operating System.
documentation: http://www.apache.org/
symbolicname: org.apache.karaf.wrapper.core
presentationname: Apache Karaf :: Wrapper :: Core
license: http://www.apache.org/licenses/LICENSE-2.0.txt
uri: file:/user/.m2/repository/org/apache/karaf/wrapper/org.apache.karaf.wrapper.core/4.0.0/org.apache.karaf.wrapper.core-4.0.0.jar
size: 1281352
version: 4.0.0
Requires:
   service:(&(service=org.apache.aries.blueprint.NamespaceHandler)(osgi.service.blueprint.namespace=http://aries.apache.org/blueprint/xmlns/blueprint-ext/v1.0.0))
   package:(&(package=javax.management))
   package:(&(package=org.apache.karaf.wrapper))
   package:(&(package=org.apache.karaf.wrapper.management))
   package:(&(package=org.fusesource.jansi)(version>=1.11.0)(!(version>=2.0.0)))
   package:(&(package=org.osgi.framework)(version>=1.7.0)(!(version>=2.0.0)))
   package:(&(package=org.osgi.framework.launch)(version>=1.1.0)(!(version>=2.0.0)))
   package:(&(package=org.osgi.framework.startlevel)(version>=1.0.0)(!(version>=2.0.0)))
   package:(&(package=org.osgi.service.blueprint)(version>=1.0.0)(!(version>=2.0.0)))
   package:(&(package=org.slf4j)(version>=1.7.0)(!(version>=2.0.0)))
Capabilities:
   bundle:{manifestversion=2, symbolicname=org.apache.karaf.wrapper.core, presentationname=Apache Karaf :: Wrapper :: Core, version=4.0.0}
   service:{service=org.apache.karaf.wrapper.WrapperService}
   package:{package=org.apache.karaf.wrapper, version=4.0.0}
   package:{package=org.apache.karaf.wrapper.management, uses:=javax.management, version=4.0.0}

The obr:info command uses the following syntax to identify the bundles: symbolic_name,version where version is optional. It means that you have to use the following command to see the info about the wrapper core bundle with version 4.0.0:

karaf@root()> obr:info org.apache.karaf.wrapper.core,4.0.0
...

You can specific multiple bundles separated by space:

karaf@root()> obr:info org.apache.karaf.wrapper.core,4.0.0 org.apache.karaf.wrapper.command,4.0.0
...

`obr:source`

In addition of the bundles executable, the OBR service can also store the bundles sources.

The obr:source command check the source URL in the OBR metadata for a given bundle, and download the sources on a target folder:

karaf@root()> obr:source /tmp org.apache.karaf.wrapper.core

The obr:source command uses the following syntax to identify the bundles: symbolic_name,version where version is optional. It means that you have to use the following command to download the source of wrapper core bundle with version 4.0.0:

karaf@root()> obr:source /tmp org.apache.karaf.wrapper.core,4.0.0

You can specify multiple bundles separated by space:

karaf@root()> obr:source /tmp org.apache.karaf.wrapper.core,4.0.0 org.apache.karaf.wrapper.command,4.0.0
...

`obr:resolve`

The obr:resolve command displays the resolution output for a given set of requirements. Actually, it show the bundles providing the capabilities to match the requirements. It’s what the OBR service does when executing obr:deploy.

Optionally, the obr:resolve command can deploy the bundles as the obr:deploy command does.

For instance, to know the OBR bundle resolving the org.apache.karaf.wrapper package requirement, you can do:

karaf@root()> obr:resolve package=org.apache.karaf.wrapper
Required resource(s):
---------------------
   Apache Karaf :: Wrapper :: Core (4.0.0)

`obr:find`

The obr:find command is similar to the obr:resolve one. It displays the bundles resolving the provided requirements, with details.

For instance, to find the OBR bundle providing the org.apache.karaf.wrapper package, you can do:

karaf@root()> obr:find package=org.apache.karaf.wrapper
-------------------------------
Apache Karaf :: Wrapper :: Core
-------------------------------
id: org.apache.karaf.wrapper.core/4.0.0
description: Core implementation and integration of the Java Service Wrapper.        It provides a complete integration of Karaf with your Operating System.
documentation: http://www.apache.org/
symbolicname: org.apache.karaf.wrapper.core
presentationname: Apache Karaf :: Wrapper :: Core
license: http://www.apache.org/licenses/LICENSE-2.0.txt
uri: file:/user/.m2/repository/org/apache/karaf/wrapper/org.apache.karaf.wrapper.core/4.0.0/org.apache.karaf.wrapper.core-4.0.0.jar
size: 1281352
version: 4.0.0
Requirements:
   service:(&(service=org.apache.aries.blueprint.NamespaceHandler)(osgi.service.blueprint.namespace=http://aries.apache.org/blueprint/xmlns/blueprint-ext/v1.0.0))
   package:(&(package=javax.management))
   package:(&(package=org.apache.karaf.wrapper))
   package:(&(package=org.apache.karaf.wrapper.management))
   package:(&(package=org.fusesource.jansi)(version>=1.11.0)(!(version>=2.0.0)))
   package:(&(package=org.osgi.framework)(version>=1.7.0)(!(version>=2.0.0)))
   package:(&(package=org.osgi.framework.launch)(version>=1.1.0)(!(version>=2.0.0)))
   package:(&(package=org.osgi.framework.startlevel)(version>=1.0.0)(!(version>=2.0.0)))
   package:(&(package=org.osgi.service.blueprint)(version>=1.0.0)(!(version>=2.0.0)))
   package:(&(package=org.slf4j)(version>=1.7.0)(!(version>=2.0.0)))
Capabilities:
   bundle:{manifestversion=2, symbolicname=org.apache.karaf.wrapper.core, presentationname=Apache Karaf :: Wrapper :: Core, version=4.0.0}
   service:{service=org.apache.karaf.wrapper.WrapperService}
   package:{package=org.apache.karaf.wrapper, version=4.0.0}
   package:{package=org.apache.karaf.wrapper.management, uses:=javax.management, version=4.0.0}

`obr:deploy`

The obr:deploy command installs a bundle from the OBR repository, including all bundles required to satisfy the bundle requirements.

karaf@root()> obr:deploy org.ops4j.pax.web.samples.helloworld-hs
Target resource(s):
-------------------
   OPS4J Pax Web - Samples - Hello World - HttpService (4.0.0.SNAPSHOT)

Required resource(s):
---------------------
   Apache ServiceMix :: Specs :: Activation API 1.4 (2.3.0.SNAPSHOT)
   OPS4J Pax Web - Jetty Bundle (4.0.0.SNAPSHOT)

Deploying...done.

By default, the bundles are just installed, not started. You can use the -s option to start the bundles.

The obr:deploy command uses the following syntax to identify the bundles: symbolic_name,version where version is optional. It means that you have to use the following command to deploy the wrapper core bundle with version 4.0.0:

karaf@root()> obr:deploy org.apache.karaf.wrapper.core,4.0.0

You can specify multiple bundles separated by space:

karaf@root()> obr:deploy org.apache.karaf.wrapper.core,4.0.0 org.apache.karaf.wrapper.command,4.0.0
...

4.16.3. `obr:start`

The obr:start command does the same as obr:deploy -s command. It installs the bundle (and all required bundles to satisfy the requirements) and starts all installed bundles.

karaf@root()> obr:start org.ops4j.pax.web.samples.helloworld-hs
Target resource(s):
-------------------
   OPS4J Pax Web - Samples - Hello World - HttpService (4.0.0.SNAPSHOT)

Required resource(s):
---------------------
   Apache ServiceMix :: Specs :: Activation API 1.4 (2.3.0.SNAPSHOT)
   OPS4J Pax Web - Jetty Bundle (4.0.0.SNAPSHOT)

Deploying...done.

The obr:start command uses the following syntax to identify the bundles: symbolic_name,version where version is optional. It means that you have to use the following command to deploy and start the wrapper core bundle with version 4.0.0:

karaf@root()> obr:start org.apache.karaf.wrapper.core,4.0.0

You can specify multiple bundles separated by space:

karaf@root()> obr:start org.apache.karaf.wrapper.core,4.0.0 org.apache.karaf.wrapper.command,4.0.0
...

4.16.4. JMX ObrMBean

On the JMX layer, Apache Karaf provides a MBean dedicated to the management of the OBR service: the ObrMBean.

The ObjectName to use is org.apache.karaf:type=obr,name=*.

Attributes

The Urls attribute provides the list of registered OBR repositories URLs.

The Bundles attribute provides a tabular data containing all bundles available on the registered OBR repositories.

Operations

addUrl(url) registers the OBR repository using the url to the repository.xml.
removeUrl(url) removes the OBR repository at the given url.
refreshUrl(url) refreshes the OBR repository at the given url.
deployBundle(name) deploys a bundle (and all bundles required to satisfy the requirements) using the OBR service. The bundles are not automatically started.
deployBundle(name, start, deployOptional) deploys a bundle (and all bundles required to satisfy the requirements) using the OBR service. If start is true, the bundles are automatically started. If deployOptional is true, even the optional requirements will be resolved by the OBR service (meaning installing more bundles to satisfy the optional requirements).

The name to identify a bundle uses the following syntax: symbolic_name,version where version is optional.

4.16.5. Apache Karaf Cave

In addition of being an OBR client, Apache Karaf can act as an OBR repositories server, thanks to Apache Karaf Cave.

See the https://karaf.apache.org/projects.html for details.

4.17. Enterprise

4.17.1. Http Service

Apache Karaf supports several Http Services:

http feature installs Http Service powered by Pax Web
felix-http feature installs Http Service powered by Apache Felix HTTP

Installing the Http Service

If you want to use Pax Web Http Service, you have to install the http feature:

root@karaf()> feature:install http

NB: the HTTP service will be actually bound only when at least one web application will use it.

If you want to use Apache Felix Http Service, you have to install felix-http feature:

root@karaf()> feature:install felix-http

If you want to test the HTTP service, you can install the webconsole feature:

root@karaf()> feature:install webconsole

Then, you can test the HTTP service by accessing the Apache Karaf WebConsole pointing your browser to [http://localhost:8181/system/console].

Configuring the HTTPService

By default the HTTPService listens on port 8181 you can change the port by creating a file etc/org.ops4j.pax.web.cfg (if you use the Pax Web Http Service) with the following content:

org.osgi.service.http.port=8181

or by typing:

root@karaf> config:property-set -p org.ops4j.pax.web org.osgi.service.http.port 8181

If the http feature is already installed the change will take effect immediately.

If you use Apache Felix Http Service, it’s basically the same but the configuration is etc/org.apache.felix.http.cfg.

Registering a servlet with the HttpService manually

See the Apache Karaf Servlet example: https://github.com/apache/karaf/tree/master/examples/karaf-servlet-example/karaf-servlet-example-registration

Using the Pax Web whiteboard extender

The Pax Web whiteboard extender is an enhancement of the http feature. So use the following command to install:

root@karaf> feature:install http-whiteboard

NB: felix-http feature installs whiteboard by default in the feature.

You can take a look on a full example using whiteboard here: https://github.com/apache/karaf/tree/master/examples/karaf-servlet-example

For commands take a look at the command section in the webcontainer chapter.

4.17.2. WebContainer (JSP/Servlet)

Apache Karaf can act as a complete WebContainer, fully supporting the JSP/Servlet specifications.

Apache Karaf WebContainer supports both:

WAB (WebApplication Bundles) which are OSGi native web applications
WAR (WebApplication aRchives) which are non-OSGi web applications (the same as you can deploy in any web container like Apache Tomcat)

To enable the Apache Karaf WebContainer, you just have to install the war feature:

karaf@root()> feature:install war

Note	The installation of the `webconsole` feature automatically installs the `war` feature.

The war feature provides:

an embedded web container (powered by Jetty), with its configuration
a set of console commands
a new war deployer

Configuration

The default port used by the WebContainer is 8181. Note: the connector is actually bound only when at least a servlet or webapplication is using it. It means that just installing the http or war feature doesn’t bind the connector.

By default, Karaf creates an internal Jetty connector that you can configure via etc/org.ops4j.pax.web.cfg:

org.osgi.service.http.port=8181

Note: if you want to use port numbers < 1024, remember you have to run with root privileges. However note that this is not a good idea from a security point of view.

It’s possible to enable the HTTPs "internal" connector. The first step is to create a keystore containing a server certificate. For instance the following command creates a keystore with a self-signed certificate:

keytool -genkey -keyalg RSA -alias selfsigned -keystore keystore -storepass karaf1234 -validity 360 -keysize 2048

Now, we can enable and configure the HTTPs connector with this keystore in etc/org.ops4j.pax.web.cfg:

org.osgi.service.http.port.secure=8443
org.osgi.service.http.secure.enabled=true
org.ops4j.pax.web.ssl.keystore=/path/to/keystore
org.ops4j.pax.web.ssl.password=foo
org.ops4j.pax.web.ssl.keypassword=karaf1234

It’s possible to use only HTTPs and to disable the HTTP using:

org.osgi.service.http.enabled=false

org.osgi.service.https.enabled=true

As an alternative to the default connectors, it is possible to configure additional connectors in the etc/jetty.xml configuration file.

The etc/jetty.xml is a standard Eclipse Jetty configuration file.

The default Apache Karaf WebContainer etc/jetty.xml contains:

<?xml version="1.0"?>
<!--
 Licensed to the Apache Software Foundation (ASF) under one
 or more contributor license agreements.  See the NOTICE file
 distributed with this work for additional information
 regarding copyright ownership.  The ASF licenses this file
 to you under the Apache License, Version 2.0 (the
 "License"); you may not use this file except in compliance
 with the License.  You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing,
 software distributed under the License is distributed on an
 "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 KIND, either express or implied.  See the License for the
 specific language governing permissions and limitations
 under the License.
-->
<!DOCTYPE Configure PUBLIC "-//Mort Bay Consulting//
DTD Configure//EN" "http://jetty.mortbay.org/configure.dtd">

<Configure class="org.eclipse.jetty.server.Server">

    <!-- =========================================================== -->
    <!-- Set connectors -->
    <!-- =========================================================== -->
    <!-- One of each type! -->
    <!-- =========================================================== -->

    <!-- Use this connector for many frequently idle connections and for
        threadless continuations. -->
    <Call name="addConnector">
        <Arg>
            <New class="org.eclipse.jetty.server.nio.SelectChannelConnector">
                <Set name="host">
                    <Property name="jetty.host" />
                </Set>
                <Set name="port">
                    <Property name="jetty.port" default="8181" />
                </Set>
                <Set name="maxIdleTime">300000</Set>
                <Set name="Acceptors">2</Set>
                <Set name="statsOn">false</Set>
                <Set name="confidentialPort">8443</Set>
                <Set name="lowResourcesConnections">20000</Set>
                <Set name="lowResourcesMaxIdleTime">5000</Set>
            </New>
        </Arg>
    </Call>

    <!-- =========================================================== -->
    <!-- Configure Authentication Realms -->
    <!-- Realms may be configured for the entire server here, or -->
    <!-- they can be configured for a specific web app in a context -->
    <!-- configuration (see $(jetty.home)/contexts/test.xml for an -->
    <!-- example). -->
    <!-- =========================================================== -->
    <Call name="addBean">
        <Arg>
            <New class="org.eclipse.jetty.plus.jaas.JAASLoginService">
                <Set name="name">karaf</Set>
                <Set name="loginModuleName">karaf</Set>
                <Set name="roleClassNames">
                    <Array type="java.lang.String">
                        <Item>org.apache.karaf.jaas.boot.principal.RolePrincipal
                        </Item>
                    </Array>
                </Set>
            </New>
        </Arg>
    </Call>
    <Call name="addBean">
        <Arg>
            <New class="org.eclipse.jetty.plus.jaas.JAASLoginService">
                <Set name="name">default</Set>
                <Set name="loginModuleName">karaf</Set>
                <Set name="roleClassNames">
                    <Array type="java.lang.String">
                        <Item>org.apache.karaf.jaas.boot.principal.RolePrincipal
                        </Item>
                    </Array>
                </Set>
            </New>
        </Arg>
    </Call>

</Configure>

The SelectChannelConnector defines the default connector of the WebContainer.

This connector defines the 8181 port number for the HTTP protocol (port property), and the 8443 port number for the HTTPS protocol (confidentialPort property).

By default, Apache Karaf bind these ports on all network interfaces (0.0.0.0). You can config the host property to bind on a specific network interface (with a given IP address).

The following resources give you details about advanced etc/jetty.xml configurations:

Deploy

Apache Karaf WebContainer is able to deploy:

pure OSGi WebApplication Bundle (WAB)
"classical" standard WebApplication aRchive (WAR)

WAB (WebApplication Bundle)

A WAB is a standard WAR or JAR archive containing at least the following properties in the MANIFEST:

Bundle-ManifestVersion: 2 defines that the bundle follows the rules of R4 specification.
Bundle-SymbolicName specifies a unique, non-localizable name for the bundle. This name should be based on the reverse domain name convention.
Web-ContextPath specifies the location of the web application.

WAB can be deployed directly in Apache Karaf, for instance, by dropping the archive in the deploy folder, or using the bundle:install command.

For instance, the Apache Karaf manual (documentation) is available as a WAB that you can deploy directly in a running instance:

karaf@root()> bundle:install -s mvn:org.apache.karaf/manual/4.0.0/war

WAR (WebApplication aRchive)

Apache Karaf allows you to deploy directly WAR files without repackaging as WAB.

Using the webbundle prefix and providing headers directly on the URL, Apache Karaf creates a WAB "on the fly".

For instance, you can deploy the Apache Tomcat sample non-OSGi "classical" WAR with the following command:

karaf@root()> bundle:install -s "webbundle:http://tomcat.apache.org/tomcat-7.0-doc/appdev/sample/sample.war?Bundle-SymbolicName=tomcat-sample&Web-ContextPath=/sample"

You can note the webbundle prefix, and the Bundle-SymbolicName and Web-ContextPath headers on the URL.

HTTP proxy

Apache Karaf provides a HTTP proxy service. It allows you to proxy any HTTP URLs within Karaf. It allows you to expose remote web applications in Karaf.

You can use the Karaf ProxyService programmatically, or via the corresponding shell commands and MBeans.

Commands

`http:list`

The http:list lists the available Servlets deployed in the WebContainer.

For instance, if you have installed the Apache Karaf WebConsole, you can see the WebConsole Servlets:

karaf@root()> http:list
ID  | Servlet          | Servlet-Name   | State       | Alias               | Url
-----------------------------------------------------------------------------------------------------
113 | ResourceServlet  | /res           | Deployed    | /system/console/res | [/system/console/res/*]
113 | KarafOsgiManager | ServletModel-2 | Undeployed  | /system/console     | [/system/console/*]
113 | KarafOsgiManager | ServletModel-5 | Deployed    | /system/console     | [/system/console/*]

The ID is the ID of the bundle which provides the servlet (113 here).

The State is the current state of the Servlet (Deployed or Undeployed).

The Url is the URL where the Servlet is available.

`web:list`

The web:list command lists the WebApplication Bundles ("native" WAB or "wrapped WAR") deployed in the WebContainer.

For instance, if you installed the Apache Karaf manual WAR file as described previously, you can see it with web:list:

karaf@root()> web:list
ID  | State       | Web-State   | Level | Web-ContextPath | Name
---------------------------------------------------------------------------------------------------
111 | Active      | Deployed    | 80    | /karaf-doc      | Apache Karaf :: Manual (4.0.0)

`web:stop`

The web:stop command stops a web application in the WebContainer. The web:stop command expects a id argument corresponding to the bundle ID (as displayed by the web:list command).

For instance, to stop the Apache Karaf manual web application:

karaf@root()> web:stop 111

`web:start`

The web:start command starts a web application in the WebContainer. The web:start command expects a id argument corresponding to the bundle ID (as displayed by the web:list command).

For instance, to start the Apache Karaf manual web application:

karaf@root()> web:start 111

`http:proxy-list`

The http:proxy-list command list the configured HTTP proxies:

karaf@root()> http:proxy-list
URL         │ ProxyTo                              │ Balancing Policy
────────────┼──────────────────────────────────────┼─────────────────
/webconsole │ http://localhost:8181/system/console │

`http:proxy-add` and `http:proxy-balancing-list`

The http:proxy-add registers a new HTTP proxy. For instance, you can proxy the Karaf WebConsole on another URL of your choice using:

karaf@root()> http:proxy-add /webconsole http://localhost:8181/system/console

Karaf HTTP Proxy can proxy any URL, like a backend running on Docker or a remote URL.

It’s also possible to proxy several URLs, defining a balancing policy. By default, two balancing policies are available: random (selecting one URL randomly) and round-robin (selecting one URL after another one). It’s possible to create your own balancing policy by implementing a BalancingPolicy service (with the type service property).

You can see the balancing policies available using http:proxy-balancing-list command:

karaf@root()> http:proxy-balancing-list
random
round-robin

Then, you can use add a proxy with several targets and a policy:

karaf@root()> http:proxy-add -b round-robin /my http://host1/my,http://host2/my,http://host3/my

You can see the list and balancing policy in used using http:proxy-list:

karaf@root()> http:proxy-list
URL         │ ProxyTo                                         │ Balancing Policy
────────────┼─────────────────────────────────────────────────┼─────────────────
/my         │ http://host1/my,http://host2/my,http://host3/my │ round-robin

`http:proxy-remove`

The http:proxy-remove removes an existing HTTP proxy:

karaf@root()> http:proxy-remove /webconsole

JMX HttpMBean

On the JMX layer, you have a MBean dedicated to the manipulation of the Servlets: the HttpMBean.

The ObjectName to use is org.apache.karaf:type=http,name=*.

Attributes

The Servlets attribute provides a tabular data providing the list of deployed Servlets including:

Alias is the Servlet URL alias.
Bundle-ID is the ID of the bundle which provides this Servlet.
Servlet is the class name of the Servlet.
State is the current Servlet state (Deployed or Undeployed).
URL is the URL of the Servlet (the Servlet context path).

The Proxies attribute provides a tabular data providing the list of HTTP proxies including:

URL is the proxy URL.
proxyTo is the proxy target.
prefix is optional proxy prefix.

The ProxyBalacingPolicies attribute provides the collection of balancing policies available.

Operations

addProxy(url, proxyTo, prefix) registers a new HTTP proxy.
removeProxy(url) removes an existing HTTP proxy.

JMX WebMBean

On the JMX layer, you have a MBean dedicated to the manipulation of the Web Applications: the WebMBean.

The ObjectName to use is org.apache.karaf:type=web,name=*.

Attributes

The WebBundles attribute provides a tabular data providing the list of deployed Web Applications including:

ID is the ID of the bundle providing the Web Application.
Level is the bundle start level.
Name is the bundle symbolic name providing the Web Application.
State is the current state of the bundle.
Web-ContextPath is the context path of the Web Application.
Web-State is the current status of the Web Application (Deployed or Undeployed).

Operations

start(id) starts the web context of the bundle with id.
start(list) starts the web context of the bundles with ID in the provided list.
stop(id) stops the web context of the bundle with id.
stop(list) stops the web context of the bundles with ID in the provided list.

4.17.3. Naming (JNDI)

The Apache Karaf Naming (JNDI) is an optional enterprise feature.

You have to install the jndi feature first:

karaf@root()> feature:install jndi

Apache Karaf provides a complete JNDI support.

You have two parts in the Apache Karaf JNDI support:

a fully compliant implementation of the OSGi Alliance JNDI Service specification.
a more "regular" JNDI context, containing different names that you can administrate.

OSGi Services Registry and JNDI

The OSGi Service Registry provides a centralized register/query capabilities for OSGi services.

A common pattern outside of OSGi is to make use of JNDI API to access services from a directory system. The OSGi service registry can be viewed as an example of such a system.

Apache Karaf supports the osgi:service lookup scheme as defined by the JNDI Service Specification.

The schema is:

osgi:service/<interface>[/<filter>]

For instance, you can directly use JNDI to get a OSGi service:

Context ctx = new InitialContext();
Runnable r = (Runnable) ctx.lookup("osgi:service/java.lang.Runnable");

JNDI service

Apache Karaf also supports regular JNDI, including a directoy system where you can register name bindings, sub-context, etc.

It supports the standard JNDI API:

Context ctx = new InitialContext();
Runnable r = (Runnable) ctx.lookup("this/is/the/name");

It also allows you to bind some OSGi services as "pure" JNDI name. In that case, you don’t have to use the specific osgi:service scheme.

Commands

Apache Karaf provides specific commands to manipulate the JNDI service.

`jndi:names`

The jndi:names command lists all JNDI names. It groups both the JNDI names from the osgi:service scheme and the regular JNDI names:

karaf@root()> jndi:names
JNDI Name         | Class Name
------------------------------------------------------------------
osgi:service/jndi | org.apache.karaf.jndi.internal.JndiServiceImpl
jndi/service      | org.apache.karaf.jndi.internal.JndiServiceImpl

We can see here the osgi:service/jndi name (using the osgi:service scheme) and jndi/service name (using the regular JNDI service).

The jndi:names command accepts an optional context argument to list names on the given context.

For instance, you can list only names in the jndi sub-context:

karaf@root()> jndi:names jndi
JNDI Name | Class Name
----------------------------------------------------------
service   | org.apache.karaf.jndi.internal.JndiServiceImpl

Note	The `jndi:names` lists only names (the full qualified name). It means that the empty JNDI sub-contexts are not displayed. To display all JNDI sub-contexts (empty or not), you can use the `jndi:contexts` command.

`jndi:contexts`

The jndi:contexts command lists all JNDI sub-contexts:

karaf@root()> jndi:contexts
JNDI Sub-Context
----------------
other/context
foo/bar

`jndi:create`

The jndi:create command creates a new JNDI sub-context:

karaf@root()> jndi:create my/company

`jndi:delete`

The jndi:delete command deletes a JNDI sub-context:

karaf@root()> jndi:delete my/company

`jndi:alias`

The jndi:alias command creates a new JNDI name (alias) with an existing one.

The existing JNDI name can be a regular one:

karaf@root()> jndi:alias bean/services/jndi aliases/services/jndi
karaf@root()> jndi:names
JNDI Name             | Class Name
----------------------------------------------------------------------
osgi:service/jndi     | org.apache.karaf.jndi.internal.JndiServiceImpl
bean/services/jndi    | org.apache.karaf.jndi.internal.JndiServiceImpl
aliases/services/jndi | org.apache.karaf.jndi.internal.JndiServiceImpl

or a name from the osgi:service schema:

karaf@root()> jndi:alias osgi:service/jndi alias/jndi/service
karaf@root()> jndi:names
JNDI Name          | Class Name
-------------------------------------------------------------------
osgi:service/jndi  | org.apache.karaf.jndi.internal.JndiServiceImpl
alias/jndi/service | org.apache.karaf.jndi.internal.JndiServiceImpl

Note	The `jndi:alias` automatically creates all required JNDI sub-contexts.

`jndi:bind`

The jndi:bind command binds an OSGi service with a JNDI name.

The jndi:bind command requires an OSGi service ID and a JNDI name. The OSGi service ID can be found using the service:list command.

For instance, we can bind the OSGi service with ID 344 with the JNDI name services/kar:

karaf@root()> jndi:bind 344 services/kar
karaf@root()> jndi:names
JNDI Name         | Class Name
-------------------------------------------------------------------------------
osgi:service/jndi | org.apache.karaf.jndi.internal.JndiServiceImpl
services/kar      | org.apache.karaf.kar.internal.KarServiceImpl

`jndi:unbind`

The jndi:unbind command unbind a given JNDI name:

karaf@root()> jndi:names
JNDI Name         | Class Name
-------------------------------------------------------------------------------
osgi:service/jndi | org.apache.karaf.jndi.internal.JndiServiceImpl
services/kar      | org.apache.karaf.kar.internal.KarServiceImpl
karaf@root()> jndi:unbind services/kar
karaf@root()> jndi:names
JNDI Name         | Class Name
-------------------------------------------------------------------------------
osgi:service/jndi | org.apache.karaf.jndi.internal.JndiServiceImpl

Note	It’s not possible to unbind a name from the `osgi:service` schema, as it’s linked to a OSGi service.

JMX JndiMBean

The JMX JndiMBean provides the JNDI names, and the operations to manipulate the JNDI service.

The object name to use is org.apache.karaf:type=jndi,name=*.

Attributes

The Names attribute provides a map containing all JNDI names and class names from both osgi:service scheme and the regular JNDI service.

The Contexts attribute provides a list containing all JNDI sub-contexts.

Operations

getNames(context) provides a map containing JNDI names and class names in a given JNDI sub-context.
create(context) creates a new JNDI sub-context.
delete(context) deletes a JNDI sub-context.
alias(name, alias creates a JNDI name (alias) for a given one.
bind(serviceId, name binds a JNDI name using an OSGi service (identified by its ID).
unbind(name) unbinds a JNDI name.

4.17.4. Transaction (JTA)

Apache Karaf provides container managed transactions, available as OSGi services.

As most of the enterprise features, it’s an optional feature that you can install with:

karaf@root()> feature:install transaction

However, the transaction feature is installed (as a transitive dependency) when installing enterprise features (like jdbc or jms features for instance).

Apache Aries Transaction and ObjectWeb HOWL

The transaction feature uses Apache Aries and ObjectWeb HOWL. Aapache Aries Transaction "exposes" the transaction manager as an OSGi service. The actual implementation of the transaction manager is ObjectWeb HOWL.

ObjectWeb HOWL is a logger implementation providing features required by the ObjectWeb JOTM project, with a public API that is generally usable by any Transaction Manager. ObjectWeb HOWL uses unformatted binary logs to maximize performance and specifies a journalization API with methods necessary to support JOTM recovery operations.

ObjectWeb HOWL is intended to be used for logging of temporary data such as XA transaction events. It is not a replacement for traditional log kits such as LOG4J and Java SE Logging.

In Apache Karaf, ObjectWeb HOWL (High-speed ObjectWeb Logger) is used to implement TransactionLog (in Aries Transaction), providing a very performant transaction manager in an OSGi way.

Configuration

The installation of the transaction feature installs a new configuration: org.apache.aries.transaction.

You can see the configuration properties using:

karaf@root()> config:list "(service.pid=org.apache.aries.transaction)"
----------------------------------------------------------------
Pid:            org.apache.aries.transaction
BundleLocation: mvn:org.apache.aries.transaction/org.apache.aries.transaction.manager/1.1.0
Properties:
   aries.transaction.recoverable = true
   aries.transaction.timeout = 600
   service.pid = org.apache.aries.transaction
   org.apache.karaf.features.configKey = org.apache.aries.transaction
   aries.transaction.howl.maxBlocksPerFile = 512
   aries.transaction.howl.maxLogFiles = 2
   aries.transaction.howl.logFileDir = /opt/apache-karaf-4.0.0/data/txlog
   aries.transaction.howl.bufferSizeKBytes = 4

aries.transaction.recoverable property is a flag to enable support of recoverable resource or not. A recoverable resource is a transactional object whose state is saved to stable storage if the transaction is committed, and whose state can be reset to what it was at the beginning of the transaction if the transaction is rolled back. At commit time, the transaction manager uses the two-phase XA protocol when communicating with the recoverable resource to ensure transactional integrity when more than one recoverable resource is involved in the transaction being committed. Transactional databases and message brokers like Apache ActiveMQ are examples of recoverable resources. A recoverable resource is represented using the javax.transaction.xa.XAResource interface in JTA. Default is true.
aries.transaction.timeout property is the transaction timeout. If a transaction has a lifetime longer than this timeout a transaction exception is raised and the transaction is rollbacked. Default is 600 (10 minutes).
aries.transaction.howl.logFileDir property is the directory where the transaction logs (journal) are stored. Default is KARAF_DATA/txlog.
aries.transaction.howl.maxLogFiles property is the maximum number of transaction log files to retain. Combined with the aries.transaction.howl.maxBlocksPerFile, it defines the transaction retention.

You can change the configuration directly using the config:* commands, or the Config MBean.

For instance, to increase the transaction timeout, you can do:

karaf@root()> config:edit org.apache.aries.transaction
karaf@root()> config:property-set aries.transaction.timeout 1200
karaf@root()> config:update
karaf@root()> config:list "(service.pid=org.apache.aries.transaction)"
----------------------------------------------------------------
Pid:            org.apache.aries.transaction
BundleLocation: mvn:org.apache.aries.transaction/org.apache.aries.transaction.manager/1.1.0
Properties:
   aries.transaction.recoverable = true
   aries.transaction.timeout = 1200
   service.pid = org.apache.aries.transaction
   org.apache.karaf.features.configKey = org.apache.aries.transaction
   aries.transaction.howl.maxBlocksPerFile = 512
   aries.transaction.howl.maxLogFiles = 2
   aries.transaction.howl.logFileDir = /opt/apache-karaf-4.0.0/data/txlog
   aries.transaction.howl.bufferSizeKBytes = 4

Note

The transaction feature defines the configuration in memory by default. It means that changes that you can do will be lost in case of Apache Karaf restart. If you want to define your own transaction configuration at startup, you have to create a etc/org.apache.aries.transaction.cfg configuration file and set the properties and values in the file. For instance:

# etc/org.apache.aries.transaction.cfg
aries.transaction.recoverable = true
aries.transaction.timeout = 1200
aries.transaction.howl.maxBlocksPerFile = 512
aries.transaction.howl.maxLogFiles = 2
aries.transaction.howl.logFileDir = /opt/apache-karaf-4.0.0/data/txlog
aries.transaction.howl.bufferSizeKBytes = 4

4.17.5. DataSources (JDBC)

The Apache Karaf DataSources (JDBC) is an optional enterprise feature.

You have to install the following features first:

karaf@root()> feature:install jdbc

NB: jdbc feature automatically installs the pax-jdbc-* core features.

Pax JDBC provides ready to use adapters for different databases:

pax-jdbc-derby
pax-jdbc-derbyclient
pax-jdbc-h2
pax-jdbc-mariadb
pax-jdbc-mysql
pax-jdbc-oracle
pax-jdbc-postgresql
pax-jdbc-sqlite
pax-jdbc-mssql

This feature provides an OSGi service to create/delete JDBC datasources in the container and perform database operations (SQL queries).

This JDBC OSGi service can be manipulated programmatically (see the developer guide for details), using the jdbc:* commands, or using the JDBC MBean.

Commands

`jdbc:ds-factories`

The jdbc:ds-factories command lists the available datasource factories, with the available driver.

For instance, once you installed the jdbc feature, you can install pax-jdbc-postgresql feature, providing the PostgreSQL datasource factory:

karaf@root()> feature:install pax-jdbc-postgresql

Then, you can see the factory available with jdbc:ds-factories:

karaf@root()> jdbc:ds-factories
Name                   │ Class                 │ Version │ Registration bundle
───────────────────────┼───────────────────────┼─────────┼───────────────────────────
PostgreSQL JDBC Driver │ org.postgresql.Driver │ 42.2.8  │ org.postgresql.jdbc42 [51]

You can see there the JDBC driver name and class that you can use in the jdbc:ds-create command.

NB: don’t forget to install the pax-jdbc-* features for the database you want to connect:

pax-jdbc-db2
pax-jdbc-teradata
pax-jdbc-derby
pax-jdbc-derbyclient
pax-jdbc-h2
pax-jdbc-hsqldb
pax-jdbc-mariadb
pax-jdbc-oracle
pax-jdbc-postgresql
pax-jdbc-sqlite
pax-jdbc-mssql
pax-jdbc-jtds

`jdbc:ds-create`

The jdbc:ds-create command automatically creates a datasource definition file by leveraging pax-jdbc.

The jdbc:ds-create command requires either:

the --driverName containing the JDBC driver name
or the --driverClass containing the JDBC driver class name

Driver name and driver class can be found with jdbc:ds-factories command.

The jdbc:ds-create accepts a set of options and the name argument:

DESCRIPTION
        jdbc:ds-create

        Create a JDBC datasource config for pax-jdbc-config from a DataSourceFactory

SYNTAX
        jdbc:ds-create [options] name

ARGUMENTS
        name
                The JDBC datasource name

OPTIONS
        -dbName
                Database name to use
        --help
                Display this help message
        -dn, --driverName
                org.osgi.driver.name property of the DataSourceFactory
        -u, --username
                The database username
        -dc, --driverClass
                org.osgi.driver.class property  of the DataSourceFactory
        -p, --password
                The database password
        -url
                The JDBC URL to use

the name argument is required. It’s the name of the datasource. The name is used to identify the datasource, and to create the datasource definition file (deploy/datasource-[name].xml).
the -u option is optional. It defines the database username.
the -url option is optional. It defines the JDBC URL to access to the database.
the -p option is optional. It defines the database password.

For instance, to create an embedded Apache Derby database in Apache Karaf, you can do:

karaf@root()> jdbc:ds-create -dn derby -url "jdbc:derby:test;create=true" test

We can see that this command created a configuration PID containing the datasource properties.

Another example using PostgreSQL driver class name (you can find with jdbc:ds-factories command):

karaf@root()> jdbc:ds-create -dc org.postgresql.Driver -url "jdbc:postgresql://localhost:5432/test" --username user --password passwd test

or using datasource factory name (also provided by jdbc:ds-factories command):

karaf@root()> jdbc:ds-create -dn "PostgreSQL JDBC Driver" -url "jdbc:postgresql://localhost:5432/test" --username user --password passwd test

`jdbc:ds-delete`

The jdbc:ds-delete command deletes a datasource.

karaf@root()> jdbc:ds-delete test

`jdbc:ds-list`

The jdbc:ds-list command lists the JDBC datasources:

karaf@root()> jdbc:ds-list
Name │ Service Id │ Product        │ Version              │ URL             │ Status
─────┼────────────┼────────────────┼──────────────────────┼─────────────────┼───────
test │ 112        │ Apache Derby   │ 10.8.2.2 - (1181258) │ jdbc:derby:test │ OK

`jdbc:ds-info`

The jdbc:ds-info command provides details about a JDBC datasource. The data source may be specified using name or service.id:

karaf@root()> jdbc:ds-info test
Property       | Value
--------------------------------------------------
driver.version | 10.8.2.2 - (1181258)
service.id     | 112
username       | APP
db.version     | 10.8.2.2 - (1181258)
db.product     | Apache Derby
driver.name    | Apache Derby Embedded JDBC Driver
url            | jdbc:derby:test

`jdbc:execute`

The jdbc:execute command executes a SQL query that doesn’t return any result on a given JDBC datasource.

Typically, you can use the jdbc:execute command to create tables, insert values into tables, etc.

For instance, we can create a person table on our test datasource:

karaf@root()> jdbc:execute test "create table person(name varchar(100), nick varchar(100))"

And we can insert some records in the person table:

karaf@root()> jdbc:execute test "insert into person(name, nick) values('foo','bar')"
karaf@root()> jdbc:execute test "insert into person(name, nick) values('test','test')"

`jdbc:query`

The jdbc:query command is similar to the jdbc:execute one but it displays the query result.

For instance, to display the content of the person table, we can do:

karaf@root()> jdbc:query test "select * from person"
NICK       | NAME
--------------------------------
bar        | foo
test       | test

`jdbc:tables`

The jdbc:tables command displays all tables available on a given JDBC datasource:

karaf@root()> jdbc:tables test
REF_GENERATION | TYPE_NAME | TABLE_NAME       | TYPE_CAT | REMARKS | TYPE_SCHEM | TABLE_TYPE   | TABLE_SCHEM | TABLE_CAT | SELF_REFERENCING_COL_NAME
----------------------------------------------------------------------------------------------------------------------------------------------------
               |           | SYSALIASES       |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSCHECKS        |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSCOLPERMS      |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSCOLUMNS       |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSCONGLOMERATES |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSCONSTRAINTS   |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSDEPENDS       |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSFILES         |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSFOREIGNKEYS   |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSKEYS          |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSPERMS         |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSROLES         |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSROUTINEPERMS  |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSSCHEMAS       |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSSEQUENCES     |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSSTATEMENTS    |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSSTATISTICS    |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSTABLEPERMS    |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSTABLES        |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSTRIGGERS      |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSVIEWS         |          |         |            | SYSTEM TABLE | SYS         |           |
               |           | SYSDUMMY1        |          |         |            | SYSTEM TABLE | SYSIBM      |           |
               |           | PERSON           |          |         |            | TABLE        | APP         |           |

JMX JDBC MBean

The JMX JDBC MBean provides the JDBC datasources, and the operations to manipulate datasources and database.

The object name to use is org.apache.karaf:type=jdbc,name=*.

Attributes

The Datasources attribute provides a tabular data of all JDBC datasource, containing:

name is the JDBC datasource name
service.id is the JDBC datasource ID of OSGi service
product is the database product backend
url is the JDBC URL used by the datasource
version is the database version backend.

Operations

create(name, type, jdbcDriverClassName, version, url, user, password, installBundles) creates a JDBC datasource (the arguments correspond to the options of the jdbc:create command).
delete(name) deletes a JDBC datasource.
info(datasource) returns a Map (String/String) of details about a JDBC datasource.
tables(datasource) returns a tabular data containing the tables available on a JDBC datasource.
execute(datasource, command executes a SQL command on the given JDBC datasource.
query(datasource, query executes a SQL query on the given JDBC datasource and return the execution result as tabular data.

4.17.6. JMS

The Apache Karaf MOM (Messaging Oriented Middleware/JMS) is an optional enterprise feature.

You have to install the jms feature first:

karaf@root()> feature:install jms

The jms feature doesn’t install a JMS broker: it just installs the OSGi service, commands, and MBean to interact with a JMS broker (not the broker itself).

It means that you have to install a JMS broker itself.

This JMS broker can be available:

outside of Apache Karaf, as a standalone broker. In that case, Apache Karaf JMS will remotely connect to the JMS broker. For instance, you can use this topology with Apache ActiveMQ or IBM WebsphereMQ.
embedded in Apache Karaf. With this topology, Apache Karaf itself provides a JMS broker service. Apache ActiveMQ provides a native support in Apache Karaf.

For instance, you can install Apache ActiveMQ directly in Apache Karaf:

karaf@root()> feature:repo-add activemq
Adding feature url mvn:org.apache.activemq/activemq-karaf/LATEST/xml/features
karaf@root()> feature:install activemq-broker

The activemq-broker feature installs:

a Apache ActiveMQ broker directly in Apache Karaf, binding to the 61616 port number by default.
the Apache ActiveMQ WebConsole bound to http://0.0.0.0:8181/activemqweb by default.

The Apache Karaf jms feature provides an OSGi service to create/delete JMS connection factories in the container and perform JMS operations (send or consume messages, get information about a JMS broker, list the destinations, …).

This JMS OSGi service can be manipulated programmatically (see the developer guide for details), using the jms:* commands, or using the JMS MBean.

Commands

`jms:create`

The jms:create command creates a JMS connection factory in the Apache Karaf container. It automatically creates a blueprint XML file in the deploy folder containing the JMS connection factory definition corresponding to the type that you mentioned.

The jms:create command accepts different arguments and options:

karaf@root()> jms:create --help
DESCRIPTION
        jms:create

        Create a JMS connection factory.

SYNTAX
        jms:create [options] name

ARGUMENTS
        name
                The JMS connection factory name
                (required)

OPTIONS
        -t, --type
                The JMS connection factory type (ActiveMQ, Artemis or WebsphereMQ)
                (defaults to activemq)
        --pool
                The pool mechanism to use for this connection factory
                (defaults to pooledjms)
        --help
                Display this help message
        --url
                URL of the JMS broker. For WebsphereMQ type, the URL is hostname/port/queuemanager/channel
                (defaults to tcp://localhost:61616)
        -p, --password
                Password to connect to the JMS broker
                (defaults to karaf)
        -u, --username
                Username to connect to the JMS broker
                (defaults to karaf)

the name argument is required. It’s the name of the JMS connection factory. The name is used to identify the connection factory, and to create the connection factory definition file (deploy/connectionfactory-[name].xml).
the -t (--type) option is required. It’s the type of the JMS connection factory. Currently only activemq and webspheremq types are supported. If you want to use another type of JMS connection factory, you can create the deploy/connectionfactory-[name].xml file by hand (using one as template).
the --url option is required. It’s the URL used by the JMS connection factory to connect to the broker. If the type is activemq, the URL looks like tcp://localhost:61616. If the type is webspheremq, the URL looks like host/port/queuemanager/channel.
the -u (--username) option is optional (karaf by default). In the case of the broker requires authentication, it’s the username used.
the -p (--password) option is optional (karaf by default). In the case of the broker requires authentication, it’s the password used.
the --pool option is optional (pooledjms by default). It allows you to define the pooling framework you want to use: pooledjms, narayana, transx.

For instance, to create a JMS connection factory for a Apache ActiveMQ broker, you can do:

karaf@root()> feature:install pax-jms-activemq
karaf@root()> jms:create -t activemq --url tcp://localhost:61616 test

Note	When you use ActiveMQ, Karaf uses `transx` as connection factory pooling framework.

Note

The jms:create command doesn’t install any feature or bundle providing the JMS connection factory classes (and dependencies). You have to install the required features (for instance activemq-broker feature for Apache ActiveMQ), or bundles (for IBM WebsphereMQ) providing the JMS connection factory packages and classes.

In the previous example, we assume that you previously installed the activemq-broker feature.

We can see the created JMS connection factory:

karaf@root()> la
...
151 | Active   |  80 | 0.0.0                 | connectionfactory-test.xml

The connectionfactory-test.xml file has been created in the deploy folder.

By default, the jms:create command constructs a JNDI name for the connection factory: /jms/[name].

It means that the connection factory name to use for the other jms:* commands is /jms/[name].

`jms:delete`

The jms:delete command deletes a JMS connection factory. The name argument is the name that you used at creation time:

karaf@root()> jms:delete test

`jms:connectionfactories`

The jms:connectionfactories command lists the JMS connection factories:

karaf@root()> jms:connectionfactories
JMS Connection Factory
----------------------
/jms/test