Karaf Users' Guide

2. Quick Start

1. Overview

Here is a short list of features supported by the Karaf:

• Hot deployment: Karaf supports hot deployment of OSGi bundles by monitoring jar files inside the [home]/deploy directory. Each time a jar is copied in this folder, it will be installed inside the runtime. You can then update or delete it and changes will be handled automatically. In addition, the Karaf also supports exploded bundles and custom deployers (blueprint and spring ones are included by default).
• Dynamic configuration: Services are usually configured through the ConfigurationAdmin OSGi service. Such configuration can be defined in Karaf using property files inside the [home]/etc directory. These configurations are monitored and changes on the properties files will be propagated to the services.
• Logging System: using a centralized logging back end supported by Log4J, Karaf supports a number of different APIs (JDK 1.4, JCL, SLF4J, Avalon, Tomcat, OSGi)
• Provisioning: Provisioning of libraries or applications can be done through a number of different ways, by which they will be downloaded locally, installed and started.
• Native OS integration: Karaf can be integrated into your own Operating System as a service so that the lifecycle will be bound to your Operating System.
• Extensible Shell console: Karaf features a nice text console where you can manage the services, install new applications or libraries and manage their state. This shell is easily extensible by deploying new commands dynamically along with new features or applications.
• Remote access: use any SSH client to connect to Karaf and issue commands in the console
• Security framework based on JAAS
• Managing instances: Karaf provides simple commands for managing multiple instances. You can easily create, delete, start and stop instances of Karaf through the console.
• Supports the latest OSGi 4.2 containers: Apache Felix Framework 3.0 and Eclipse Equinox 3.6

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Karaf Users' Guide

2. Quick Start

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2. Quick start

If you are in a hurry to have Apache Karaf up and running right away, this section will provide you with some basic steps for downloading, building (when needed) and running the server in no time. This is clearly not a complete guide so you may want to check other sections of this guide for further information.

All you need is 5 to 10 minutes and to follow these basic steps.

• #Background
• #Getting the software
• #Start the server
• #Deploy a sample application

Background

Apache Karaf is a small and lightweight OSGi based runtime. This provides a small lightweight container onto which various bundles can be deployed.

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Getting the software

At this time you have one option to get the software. The fastest and easiest way is to get the binary directly from the Apache site. Since this article is intended to help you to have Apache Karaf up and running in the fastest way only the binary download will be covered at this time.

Prerequisites

Although this installation path is the fastest one, still you will need to install some software before installing Karaf.

Karaf requires a Java 5 environment to run. Refer to http://java.sun.com for details on how to download and install J2SE 1.5 or greater.

Download binaries

Depending on the platform you plan to install and run Karaf you will select the appropriate installation image. Open a Web browser and access the following URL, there you will find the available packages for download (binaries and source code).

http://karaf.apache.org/download.html

Select the file compression format compatible with your system (zip for windows, tar.gz for unixes) by clicking directly on the link, download it and expand the binary to your hard drive in a new directory; for example in z:\karaf - from now on this directory will be referenced as <KARAF_HOME>. Please remember the restrictions concerning illegal characters in Java paths, e.g. !, % etc.

The installation of Karaf is as simple as uncompressing the .zip or .tar files. The next step is to start the server.

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Start the server

With Karaf already installed, open a command line console and change directory to <KARAF_HOME>. To start the server, run the following command in Windows:

respectively on Unix:

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

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

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

Note that the console supports tab completion, so you just need to enter ad <tab> cr <tab> instead of admin:create.
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Deploy a sample application

While you will learn in the remainder of this guide how to use and leverage Apache Karaf, we will just use the pre-built packaging for now.

In the console, run the following commands:

The example installed is using Camel to start a timer every 2 seconds and output a message on the console. The previous commands download the Camel features descriptor and install the example feature.

Stopping and uninstalling the sample application

To stop this demo, run the following command:

Common Problems

1. Launching Karaf can result in a deadlock in Felix during module dependency resolution. This is often a result of sending a SIGINT (control-C) to the process when it will not cleanly exit. This can corrupt the caches and cause startup problems in the very next launch. It is fixed by emptying the component cache: rm -rf data/cache/*

Stopping Karaf

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

Alternatively, you can also run the following command:

Summary

This document showed you how simple it is to have Apache Karaf up and running. The overall time for getting the server running should be less than five minutes if you have the prerequisite (Java 1.5) already installed. Additionally, this article also showed you how to deploy and test a simple Apache Camel application in less than five minutes.

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2.1. Quick Start (Source)

If you are in a hurry to have Apache Karaf up and running right away, this section will provide you with some basic steps for checking out, building and running the server in no time. This is clearly not a complete guide so you may want to check other sections of this guide for further information.

All you need is 15 minutes and to follow these basic steps.

• #Background
• #Getting the software
• #Start the server
• #Deploy a sample application

Background

Apache Karaf is a small and lightweight OSGi based runtime. This provides a small lightweight container onto which various bundles can be deployed.

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Getting the software

This document describes how to build the server from the latest Karaf source.

Prerequisites

Although this installation path is the fastest one, still you will need to install some software before installing Karaf.

Karaf requires a Java 5 environment to run. Refer to http://java.sun.com for details on how to download and install J2SE 1.5 or greater.

Subversion is required to checkout the source.

Maven 2 is required to build Karaf.

Checkout Source

The Karaf source is found at http://svn.apache.org/repos/asf/karaf/trunk/. To check out with a command line client:

Build

Change directory to the top level of the source checkout. Build Karaf using Maven as follows:

Distributions will be created in assembly/target. Select the file compression format compatible with your system (apache-karaf-2.0.0.zip for windows, apache-karaf-2.0.0.tar.gz for unixes) and expand the binary in a new directory; for example in z:\karaf - from now on this directory will be referenced as <KARAF_HOME>. Please remember the restrictions concerning illegal characters in Java paths, e.g. !, % etc.

The installation of Karaf is as simple as uncompressing the .zip or .tar files. The next step is to start the server.

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Start the server

With Karaf already installed, open a command line console and change directory to <KARAF_HOME>. To start the server, run the following command in Windows:

respectively on Unix:

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

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

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Deploy a sample application

While you will learn in the remainder of this guide how to use and leverage Apache Felix Karaf, we will just use the pre-built packaging for now.

In the console, run the following commands:

This commands will download, install and start the specified jars.

The example installed is using Camel to start a timer every 2 seconds and output a message on the console.

Stopping and uninstalling the sample application

To stop this demo, run the following command:

In the output, locate the line containing camel-example-osgi and note the id of the bundle in the first column. Then launch the following command:

If you wish, you can start again the sample by using the following command:

To uninstall the demo, run the following command:

Common Problems

1. Launching SMX4 can result in a deadlock in Felix during module dependency resolution. This is often a result of sending a SIGINT (control-C) to the process when it will not cleanly exit. This can corrupt the caches and cause startup problems in the very next launch. It is fixed by emptying the component cache: rm -rf data/cache/*

Stopping Karaf

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

Alternatively, you can also run the following command:

Summary

This document showed you how simple it is to have Apache Karaf up and running. The overall time for getting the server running should be less than five minutes if you have the prerequisite (Java 1.5) already installed. Additionally, this article also showed you how to deploy and test a simple Apache Camel application in less than five minutes.

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3. Installation

This document describes how to install and configure Apache Karaf for both Unix and Windows' platforms.
Here you will find information about what are pre requisite software, where to download Karaf from and how to customize the installation to use custom ports other than the defaults.

This article contains the following sections:

Pre-Installation Requirements

Hardware:

• 5 MB of free disk space for the Apache Karaf x.y binary distribution.
• 3 MB of free disk space for the Apache Karaf x.y source distributions or SVN checkout. The Maven build requires roughly 57 MB disk space and for the dependencies Maven downloads during building further 76 MB are required. As a lot of small files are produced, the exact space demands depend greatly on your cluster utilization ratio.

Operating Systems:

• Windows: Windows XP SP2, Windows 2000.
• Unix: Ubuntu Linux, Powerdog Linux, MacOS, AIX, HP-UX, Solaris, any Unix platform that supports Java.

Environment:

• Java Developer Kit (JDK) 1.5.x or greater (http://java.sun.com/).
• The JAVA_HOME environment variable must be set to the directory where the JDK is installed, e.g., c:\Program Files\jdk.1.5.0_06. To accomplish that, press Windows key and Break key together, switch to "Advanced" tab and click on "Environment Variables". Here, check for the variable and, if necessary, add it.
• Apache Maven 2.0.9 (http://maven.apache.org/download.html).

Installation Procedure for Windows

This section of the Getting Started guide explains how to install binary and source distributions of Karaf on a Windows system.

Windows Binary Installation

This procedure explains how to download and install the binary distribution on a Windows system.

1. From a browser, navigate to http://karaf.apache.org/download.html.
2. Scroll down to the "Apache Karaf" section and select the desired distribution.
   For a binary distribution, the filename will be similar to: apache-karaf-x.y.zip.
3. Extract the files from the ZIP file into a directory of your choice. Please remember the restrictions concerning illegal characters in Java paths, e.g. !, % etc.
4. Proceed to the #Starting Karaf section of this document.
5. Following start-up, go to the #Testing the Installation section of this document.
6. Optional: see 7.1. Enabling Colorized Console Output On Windows

Windows Source Installation

This procedure explains how to download and install the source distribution on a Windows system. NOTE: Karaf requires Java 5 is compile, build and run.

1. From a browser, navigate to http://karaf.apache.org/download.html.
2. Scroll down to the "Apache Karaf" section and select the desired distribution.
   For a source distribution, the filename will be similar to: apache-karaf-x.y-src.zip.
3. Extract Karaf from the ZIP file into a directory of your choice. Please remember the restrictions concerning illegal characters in Java paths, e.g. !, % etc.
4. Windows Source Installation Build Karaf using Maven 2.0.9 or greater and Java 5.
   The recommended method of building Karaf is the following: cd [karaf_install_dir]\\src where [karaf_install_dir] is the directory in which Karaf was installed. mvn Both steps take around 10 to 15 minutes.
5. Unzip the distribution using your favorite zip tool. The windows distribution is available at \[karaf_install_dir\]\assembly\target\apache-karaf-x.y.zip
6. Proceed to the #Starting Karaf section of this document.
7. Following start-up, go to the #Testing the Installation section of this document.
8. Optional: see 7.1. Enabling Colorized Console Output On Windows

Installation Procedure For Unix

Unix Binary Installation

This procedure explains how to download and install the binary distribution on a Unix system.

1. From a browser, navigate to http://karaf.apache.org/download.html.
2. Scroll down to the "Apache Karaf" section and select the desired distribution.
   For a binary Unix distribution, the filename will be similar to: apache-karaf-x.y.tar.gz.
3. Extract the files from the gzip file into a directory of your choice. For example: gunzip apache-karaf-x.y.tar.gz tar xvf apache-karaf-x.y.tar Please remember the restrictions concerning illegal characters in Java paths, e.g. !, % etc.
4. Proceed to the #Starting Karaf section of this document.
5. Following start-up, go to the #Testing the Installation section.

Unix Source Installation

This procedure explains how to download and install the source distribution on a Unix system. This procedure assumes the Unix machine has a browser. Please see the previous #Unix Binary Installation section for ideas on how to install Karaf without a browser. NOTE: Karaf requires Java 5 to compile, build and run.

1. From a browser, navigate to http://karaf.apache.org/download.html.
2. Scroll down to the "Apache Karaf" section and select the desired distribution.
   For a source distribution, the filename will be similar to: apache-karaf-x.y-src.tar.gz.
3. Extract the files from the ZIP file into a directory of your choice. For example: gunzip apache-karaf-x.y-src.tar.gz tar xvf apache-karaf-x.y-src.tar Please remember the restrictions concerning illegal characters in Java paths, e.g. !, % etc.
4. Build Karaf using Maven 2.0.8 or greater and Java 5: The preferred method of building Karaf is the following: cd [karaf_install_dir]/src where [karaf_install_dir] is the directory in which Karaf was installed. mvn
5. Uncompress the distribution that has just been created cd [karaf_install_dir]/assembly/target gunzip apache-karaf-x.y.tar.gz tar xvf apache-karaf-x.y.tar
6. Proceed to the #Starting Karaf section of this document.
7. Following start-up, go to the #Testing the Installation section.

Starting Karaf

On Windows

From a console window, change to the installation directory and run Karaf. For the binary distribution, go to

and for the source distribution go to the target directory, for example:

where karaf_install_dir is the directory in which Karaf was installed, e.g., c:\Program Files\apache-karaf-x.y.

Then type:

Note: Working directories get created relative to the current directory. For the working directories to be created in the proper place, Karaf must be launched from its home/installation directory.

It will start a Karaf console, allowing you to administrate your Karaf instance.

You can launch Karaf in server mode (without terminal output):

On Unix

From a command shell, change to the installation directory and run Karaf. For the binary distribution, go to

and for the source distribution go to the target directory, for example:

where karaf_install_dir is the directory in which Karaf was installed, e.g., /usr/local/apache-karaf-x.y.

Then type:

Testing the Installation and connecting to a running Karaf

If Karaf is up and running without problems, the Window's console window or the Unix command shell will display something similar to the following log line:

You can use the client mode to connect to a running Karaf:
On Windows:

On Unix:

Stopping Karaf

For both Windows and Unix installations, you can perform a clean shutdown of Karaf by using the following command:

You can use the stop script too:
On Windows:

On Unix:

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3. Installation

Karaf Users' Guide

5. Using Karaf

4. Understanding Karaf

• 4.1. Console and Commands
• 4.2. Remote Console
• 4.3. Logging system
• 4.4. Deployer
• 4.5. Security framework
• 4.6. Provisioning
• 4.7. Administration
• 4.8. Configuration
• 4.9. Wrapper

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3. Installation

Karaf Users' Guide

5. Using Karaf

4. Understanding Karaf

4.2. Remote Console

4.1. Console and Commands

Overview

Karaf provides a powerful console and a set of commands that can be used to perform various tasks. Commands can be located in the root shell or in a sub-shell. A sub-shell is a group of related commands, like commands related to the OSGi framework or the log system.

The following shells are available out-of-the-box, but the console can be easily extended:

• admin
• config
• features
• log
• obr
• osgi
• package
• shell
• ssh
• wrapper

Admin shell

This shell is described extensively in section 4.7. Administration.

Config shell

This shell is described extensively in section 4.8. Configuration.

Features shell

The features shell contains a few commands to provision entire applications easily.
More information is available on the chapter 4.6. Provisioning.

Log shell

The log shell contains a few commands to display the log entries, retrieve or change the log levels:

See the documentation on the logging system for more informations.

OBR shell

OBR (OSGi Bundle Repository) is a proposed specification that defines an xml format for repositories of OSGi bundles and an associated service to access it. Karaf proposes a number of commands that can be used to deal with such repositories.

Note that this feature is not installed by default. To install it, you must run the following command:

karaf@root:/> features:install obr

OSGi shell

The OSGi sub-shell provides commands for managing the OSGi framework: listing OSGi bundles, services, managing bundle lifecycles.
Look at the online help (launch osgi help command) for more informations.

Package shell

Shell shell

Examples:

cat mvn:org.apache.servicemix/servicemix/3.2.1/pom

or

log:display | grep error

SSH shell

Wrapper shell

Note that this feature is not installed by default. To install it, you must run the following command:

karaf@root:/> features:install wrapper

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4. Understanding Karaf

4.2. Remote Console

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4.2. Remote Console

The remote console feature allows to connect to a running Karaf instance from a remote computer and perform all the operations that are usually accessible from the local console.

Launch options

The Karaf shell scripts supports a number of options to control the remote console:

• console: launch Karaf in the default mode (both local and remote console activated). This is the default mode
• server: launch Karaf in with a remote console but no local console
• client: launch Karaf in with a local console only

These options affect two system properties that can be set if you don't use the standard shell scripts:

• karaf.startLocalConsole
• karaf.startRemoteShell

Using the client jar

It is also possible to use a more lightweight way to connect to a Karaf instance using the following command line:

There are a few parameters that can be set on the command line to change the URL used to connect to Karaf, the user or the password.
All these parameters are detailed in the help screen:

For example, to shut down Karaf from the command line, you can run the following command:

The client jar also supports passing command line arguments to the remote Karaf.

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Using an SSH client

You can use any standard SSH client to connect to a Karaf instance. The default port is 8101.

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Using another Karaf instance

First, open a terminal and launch Karaf in server mode (you could use a Karaf instance in console mode too):

On another terminal, start another Karaf instance in client mode:

Once the console appears, you can run the remote rsh command to connect to the other Kernel:

To verify that your are connected to the remote instance, run the following command:

and check the system informations.

Configuration

The TCP port is configured at the following location:

The defaut configuration is as below:

The port used can easily be changed by changing the default port 8101 in the sshPort property.

The security realm used by the console when authenticating remote users is named karaf, so you can override this realm as explained in the security section.

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4.2. Remote Console

4. Understanding Karaf

4.4. Deployer

4.3. Logging system

Karaf provides a powerful logging system based on OPS4j Pax Logging.

In addition to being a standard OSGi Log service, it supports the following APIs:

• Apache Commons Logging
• SLF4J
• Apache Log4j
• Java Util Logging

Karaf also comes with a set of console commands that can be used to display, view and change the log levels.

Configuration

The configuration of the logging system uses a standard Log4j configuration file at the following location:

[karaf]/etc/org.ops4j.pax.logging.cfg

You can edit this file at runtime and any change will be reloaded and be effective immediately.

Commands

The log subshell comes with 3 commands:

• log:display: display the last log entries
• log:display-exception: display the last exception from the log
• log:get: show the log levels
• log:set: set the log levels

For example, if you want to debug something, you might want to run the following commands:

> log:set DEBUG
... do something ...
> log:display

Note that the log levels set using the log:set commands are not persistent and will be lost upon restart.
To configure those in a persistent way, you should edit the configuration file mentioned above.
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4.2. Remote Console

4. Understanding Karaf

4.4. Deployer

4.3. Logging system

4. Understanding Karaf

4.5. Security framework

4.4. Deployer

The following picture describes the architecture of the deployer.

Spring deployer

Karaf includes a deployer that is able to deploy plain blueprint or spring-dm configuration files.
The deployer will transform on the fly any spring configuration file dropped into the deploy folder 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]
Spring-Context: *;publish-context:=false;create-asynchronously:=true
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 spring 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 spring configuration:

<spring:beans ...>
  <manifest>
    Require-Bundle= my-bundle
  </manifest>

Features deployer

To be able to hot deploy features from the deploy folder, you can just drop a feature descriptor on that folder. A bundle will be created and its installation (automatic) will trigger the installation of all features contained in the descriptor. Removing the file from the deploy folder will uninstall the features.
If you want to install a single feature, you can do so by writing a feature descriptor like the following:

<features>
  <repository>mvn:org.apache.servicemix.nmr/apache-servicemix-nmr/1.0.0/xml/features</repository>
  <feature name="nmr-only">
    <feature>nmr</feature>
  </feature>
</features>

For more informations about features, see the provisioning section.

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4.3. Logging system

4. Understanding Karaf

4.5. Security framework

4.4. Deployer

4. Understanding Karaf

4.6. Provisioning

4.5. Security framework

Karaf supports JAAS with some enhancements to allow JAAS to work nicely in an OSGi environment. This framework also features an OSGi keystore manager with the ability to deploy new keystores or truststores at runtime.

Overview

This feature allow the deployment at runtime of JAAS based configuration for use in various parts of the application. This includes the remote console login, which uses the karaf realm, but which is configured with a dummy login module by default. These realms can also be used by the NMR, JBI components or the JMX server to authenticate users logging in or sending messages into the bus.

In addition to JAAS realms, you can also deploy keystores and truststores to secure the remote shell console, setting up HTTPS connectors or using certificates for WS-Security.

A very simple XML schema for spring has been defined, allowing the deployment of a new realm or a new keystore very easily.

Schema

To deploy a new realm, you can use the following XSD which is supported by a Spring namespace handler and can thus be defined in a spring xml configuration file.

<xs:schema elementFormDefault='qualified'
           targetNamespace='http://karaf.apache.org/xmlns/jaas/v1.0.0'
           xmlns:xs='http://www.w3.org/2001/XMLSchema'
           xmlns:bp="http://www.osgi.org/xmlns/blueprint/v1.0.0"
           xmlns:tns='http://karaf.apache.org/xmlns/jaas/v1.0.0'>

    <xs:import namespace="http://www.osgi.org/xmlns/blueprint/v1.0.0"/>

    <xs:element name="config">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="module" minOccurs="0" maxOccurs="unbounded">
                    <xs:complexType mixed="true">
                        <xs:attribute name="className" use="required" type="xs:string" />
                        <xs:attribute name="flags" default="required">
                            <xs:simpleType>
                                <xs:restriction base="xs:NMTOKEN">
                                    <xs:enumeration value="required"/>
                                    <xs:enumeration value="requisite"/>
                                    <xs:enumeration value="sufficient"/>
                                    <xs:enumeration value="optional"/>
                                </xs:restriction>
                            </xs:simpleType>
                        </xs:attribute>
                    </xs:complexType>
                </xs:element>
            </xs:sequence>
            <xs:attribute name="name" use="required" type="xs:string" />
            <xs:attribute name="rank" use="optional" default="0" type="xs:int" />
        </xs:complexType>
    </xs:element>

    <xs:element name="keystore">
        <xs:complexType>
            <xs:attribute name="name" use="required" type="xs:string" />
            <xs:attribute name="rank" use="optional" default="0" type="xs:int" />
            <xs:attribute name="path" use="required" type="xs:string" />
            <xs:attribute name="keystorePassword" use="optional" type="xs:string" />
            <xs:attribute name="keyPasswords" use="optional" type="xs:string" />
        </xs:complexType>
    </xs:element>
    
</xs:schema>

You can find the schema at the following location.

Here are two example using this schema:

<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
           xmlns:jaas="http://karaf.apache.org/xmlns/jaas/v1.0.0"
           xmlns:ext="http://aries.apache.org/blueprint/xmlns/blueprint-ext/v1.0.0">

    <!-- Bean to allow the $[karaf.base] property to be correctly resolved -->
    <ext:property-placeholder placeholder-prefix="$[" placeholder-suffix="]"/>

    <jaas:config name="karaf">
        <jaas:module className="org.apache.karaf.jaas.modules.properties.PropertiesLoginModule" flags="required">
            users = $[karaf.base]/etc/users.properties
        </jaas:module>
    </jaas:config>

</blueprint>

<jaas:keystore xmlns:jaas="http://karaf.apache.org/xmlns/jaas/v1.0.0"
               id="keystore"
               name="ks"
               rank="1"
               path="classpath:privatestore.jks"
               keystorePassword="keyStorePassword"
               keyPasswords="myalias=myAliasPassword">
</jaas:keystore>

The id attribute is the blueprint id of the bean, but it will be used by default as the name of the realm if no name attribute is specified. Additional attributes on the config elements are a rank, which is an integer. When the LoginContext looks for a realm for authenticating a given user, the realms registered in the OSGi registry are matched against the required name. If more than one realm is found, the one with the highest rank will be used, thus allowing the override of some realms with new values. The last attribute is publish which can be set to false to not publish the realm in the OSGi registry, hereby disabling the use of this realm.

Each realm can contain one or more module definition. Each module identify a LoginModule and the className attribute must be set to the class name of the login module to use. Note that this login module must be available from the bundle classloader, so either it has to be defined in the bundle itself, or the needed package needs to be correctly imported. The flags attribute can take one of four values that are explained on the JAAS documentation.
The content of the module element is parsed as a properties file and will be used to further configure the login module.

Deploying such a code will lead to a JaasRealm object in the OSGi registry, which will then be used when using the JAAS login module.

Architecture

Due to constraints in the JAAS specification, one class has to be available for all bundles. This class is called ProxyLoginModule and is a LoginModule that acts as a proxy for an OSGi defines LoginModule. If you plan to integrate this feature into another OSGi runtime, this class must be made available from the system classloader and the related package be part of the boot delegation classpath (or be deployed as a fragment attached to the system bundle).

The xml schema defined above allow the use of a simple xml (leveraging spring xml extensibility) to configure and register a JAAS configuration for a given realm. This configuration will be made available into the OSGi registry as a JaasRealm and the OSGi specific Configuration will look for such services. Then the proxy login module will be able to use the information provided by the realm to actually load the class from the bundle containing the real login module.

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4.4. Deployer

4. Understanding Karaf

4.6. Provisioning

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4.6. Provisioning

Karaf provides a simple, yet flexible, way to provision applications or "features". Such a mechanism is mainly provided by a set of commands available in the features shell. The provisioning system uses xml "repositories" that define a set of features.

Commands

Repository management

The following commands can be used to manage the list of descriptors known by Karaf. They use URLs pointing to features descriptors. These URLs can use any protocol known to the Apache Karaf, the most common ones being http, file and mvn.

Karaf maintains a persistent list of these repositories so that if you add one URL and restart Karaf, the features will still be available.

The refreshUrl command is mostly used when developing features descriptors: when changing the descriptor, it can be handy to reload it in the Kernel without having to restart it or to remove then add again this URL.

Some Featue Repositories you might want to add

If you know some more URLs feel free to add them here

Features management

Examples

1. Install features using mvn handler

2. Use file handler to deploy features file

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

3. 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

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

Service configuration

A simple configuration file located in [FELIX:karaf]/etc/org.apache.karaf.features.cfg can be modified to customize the behavior when starting the Kernel for the first time.
This configuration file contains two properties:

• featuresBoot: a comma separated list of features to install at startup
• featuresRepositories: a comma separated list of feature repositories to load at startup

This configuration file is of interest if you plan to distribute Apache Karaf distribution which includes pre-installed features. Such a process is detailed in the 6.2. Custom distributions section.

Repositories

The xml features repositories use the following Relax NG Compact syntax:

Here is an example of such a repository:

A repository includes a list of feature elements, each one representing an application that can be installed. The feature is identified by its name which must be unique amongst all the repositories used and consists of a set of bundles that need to be installed along with some optional dependencies on other features and some optional configurations for the Configuration Admin OSGi service.

References to features define in other repositories are allow and can be achieved by adding a list of repository.

Remark : By default, all the features defined in a repository are not installed at the launch of Apache Karaf (see section hereafter 'h2. Service configuration' for more info).

Bundles

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:

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.

Maven URL Handler

The equivalent of the above bundle would be:

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. This flexible tool can be configured through the configuration service. For example, to find the current repositories type:

The repositories checked are controlled by these configuration properties.

For example, org.ops4j.pax.url.mvn.repositories is a comma separate list of repository URLs specifying those remote repositories to be checked. So, to replace the defaults with a new repository at http://www.example.org/repo on the local machine:

By default, snapshots are disable. To enable an URL for snapshots append @snapshots. For example

Repositories on the local are supported through file:/ URLs

Bundle start-level

Available since Karaf 2.0

By default, the bundles deployed through the feature mechanism will have a start-level equals to the value defined in the configuration file config.properties
with the variable karaf.startlevel.bundle=60. This value can be changed using the xml attribute start-level.

The advantage to define the start-level of a bundle is that you can deploy all your bundles including those of the project with the 'infrastructure' bundles required (e.g : camel, activemq)
at the same time and you will have the guaranty when you use Spring Dynamic Module (to register service through OSGI service layer), Blueprint that by example
Spring context will not be created without all the required services installed.

Bundle 'stop/start'

Available since Karaf 2.0

The OSGI specification allows to install a bundle without starting it. To use this functionality, simply add the following attribute in your <bundle> definition

Dependent features

Dependent features are useful when a given feature depends on another feature to be installed. Such a dependency can be expressed easily in the feature definition:

The effect of such a dependency is to automatically install the required nmr feature when the jbi feature will be installed.

Configurations

The configuration section allows to deploy configuration for the OSGi Configuration Admin service along a set of bundles.
Here is an example of such a configuration:

The name attribute of the configuration element will be used as the ManagedService PID for the configuration set in the Configuration Admin service. When using a ManagedServiceFactory, the name attribute is servicePid-aliasId, where servicePid is the PID of the ManagedServiceFactory and aliasId is a label used to uniquely identify a particular service (an alias to the factory generated service PID).

Deploying such a configuration has the same effect than dropping a file named com.foo.bar.cfg into the etc folder.

The content of the configuration element is set of properties parsed using the standard java property mechanism.

Such configuration as usually used with Spring-DM or Blueprint support for the Configuration Admin service, as in the following example, but using plain OSGi APIs will of course work the same way:

There may also be cases where you want to make the properties from multiple configuration files available to your bundle context. This is something you may want to do if you have a multi-bundle application where there are application properties used by multiple bundles, and each bundle has its own specific properties. In that case, <ctx:property-placeholder> won't work as it was designed to make only one configuration file available to a bundle context.
To make more than one configuration file available to your bundle-context you would do something like this:

In this example, we are using SpringDM with osgi as the primary namespace. Instead of using ctx:context-placeholder we are using the "PropertyPlaceholderConfig" class. Then we are passing in a beans array and inside of that array is where we set our osgix:cm-properties elements. This element "returns" a properties bean.

For more informations about using the Configuration Admin service in Spring-DM, see the Spring-DM documentation.

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4.6. Provisioning

4. Understanding Karaf

4.8. Configuration

4.7. Administration

Karaf provides some commands to administer multiple instances. An instance of Karaf is a copy that you can launch separately and deploy applications onto. An instance does not contain a full copy of Karaf, but only a copy of the configuration files and data folder which contains all runtime informations, logs and temporary files.

Those commands are also available from outside the OSGi environment using the admin/admin.bat script in the bin folder.

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4.6. Provisioning

4. Understanding Karaf

4.8. Configuration

4.7. Administration

4. Understanding Karaf

4.9. Wrapper

4.8. Configuration

The files in the etc directory are used to set the startup configuration.

For dynamic configuration, Karaf provides a suite of command to administer the configuration service grouped under config. To learn about all currently supported configuration commands type:

Editing

Select Configuration To Edit

For example to edit configuration foo.bar:

karaf@root:/> config:edit foo.bar

Modify Properties

Use:

• config:proplist to list existing properties
• config:propdel to delete existing properties
• config:propset to set a new value for a property

Any number of properties can be modified within a single editing session.

Commit Or Rollback Changes

Use

• config:update to commit all changes made in the current session
• config:cancel to roll back any changes made in the current session

#top

4.7. Administration

4. Understanding Karaf

4.9. Wrapper

4. Understanding Karaf

Karaf Users' Guide

6. Advanced uses

5. Using Karaf

• 5.1. Troubleshooting, Debugging, Profiling, and Monitoring
• 5.2. Developping applications
• 5.3. Creating bundles for third party dependencies
• 5.4. Writing integration tests

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4. Understanding Karaf

Karaf Users' Guide

6. Advanced uses

5.1. Troubleshooting, Debugging, Profiling, and Monitoring

5. Using Karaf

5.3. Creating bundles for third party dependencies

5.2. Developping applications

TODO

#top

5.1. Troubleshooting, Debugging, Profiling, and Monitoring

5. Using Karaf

5.3. Creating bundles for third party dependencies

5.2. Developping applications

5. Using Karaf

5.4. Writing integration tests

5.3. Creating bundles for third party dependencies

TODO

Some infos available at http://gnodet.blogspot.com/2008/09/id-like-to-talk-bit-about-third-party.html, http://blog.springsource.com/2008/02/18/creating-osgi-bundles/ and http://felix.apache.org/site/apache-felix-maven-bundle-plugin-bnd.html.

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5.2. Developping applications

5. Using Karaf

5.4. Writing integration tests

5. Using Karaf

Karaf Users' Guide

7. Optional Features

6. Advanced uses

• 6.1. Extending the console
• 6.2. Custom distributions
• 6.3. Programmatically connect to the console
• 6.4. Embedding Karaf
• 6.5. Deploying security providers
• 6.6. Installing additional features
• 6.7. Configuring Failover Deployments
• 6.9. Branding the console
• 6.10. JRE packages tuning

#top

5. Using Karaf

Karaf Users' Guide

7. Optional Features

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6.1. Extending the console

This chapter will guide you through the steps needed to extend the console and create a new shell. We will leverage Maven, Blueprint and OSGi, so you will need some knowledge of those products.

You may also find some information about the console at RFC 147 Overview.

Create the project using maven

We first need to create the project using maven. Let's leverage maven archetypes for that.

Command line

Using the command line, we can create our project:

This generate the main pom.xml and some additional packages.

Interactive shell

You can also use the interactive mode for creating the skeleton project:

Use the following values when prompted:

Manual creation

Alternatively, you can simply create the directory shell-sample-commands and create the pom.xml file inside it:

Dependencies

We need to tell maven which libraries our project depends on. In the dependencies section of the pom, add the following one:

This dependency is needed to have access to the base classes that are used to define commands.

Configuring for Java 5

We are using annotations to define commands, so we need to ensure maven will actually use JDK 1.5 to compile the jar.
Just add the following snippet after the dependencies section.

Loading the project in your IDE

We can use maven to generate the needed files for your IDE:

Inside the project, run the following command

or

The project files for your IDE should now be created. Just open the IDE and load the project.

Creating a basic command class

We can now create the command class HelloShellCommand.java

Creating the associated blueprint configuration files

The blueprint configuration file will be used to create the command and register it in the OSGi registry, which is the way to make the command available to Karaf console. This blueprint file must be located in the OSGI-INF/blueprint/ directory inside the bundle.

If you don't have the src/main/resources directory yet, create it.

Then, re-generate the IDE project files and reload it so that this folder is now recognized as a source folder.

Inside this directory, create the OSGI-INF/blueprint/ directory and put the following file inside (the name of this file has no impact at all):

Compiling the jar

Let's try to build the jar. Remove the test classes and sample classes if you used the artifact, then from the command line, run:

The end of the maven output should look like:

Turning the jar into an OSGi bundle

OSGi bundles are jars but they require some manifest headers to be correctly recognized. We will leverage Felix's maven plugin to easily generate those.

Lets turn it into a bundle: modify the line in the pom.xml to adjust the packaging:

Add the following section at the bottom of the pom.xml, in the existing build/plugins section:

The Import-Package is required to make sure our bundle will import the org.osgi.service.command package so that the service will be correctly seen in Felix.

Let's compiled it again using the mvn install command.

Test in Karaf

Launch a Karaf instance and run the following command to install the newly created bundle:

Let's try running the command:

Command completer

A completer allow you to automatically complete a command argument using <tab>. A completer is simply a bean which is injected to a command.

Of course to be able to complete it, the command should require an argument.

Command argument

We add an argument to the HelloCommand:

The Blueprint configuration file is the same as previously.

Completer bean

A completer is a bean which implements the Completer interface:

Blueprint configuration file

Using Blueprint, you can "inject" the completer linked to your command. The same completer could be used for several commands and a command can have several completers:

Test in Karaf

Launch a Karaf instance and run the following command to install the newly created bundle:

Let's try running the command:

#top

6.2. Custom distributions

6. Advanced uses

6.4. Embedding Karaf

6.3. Programmatically connect to the console

A connection to Karaf console can also be done programmatically.
The following code is a simplified version of the code from the client library.

import org.apache.sshd.ClientChannel;
import org.apache.sshd.ClientSession;
import org.apache.sshd.SshClient;
import org.apache.sshd.client.future.ConnectFuture;

public class Main {

    public static void main(String[] args) throws Exception {
        String host = "localhost";
        int port = 8101;
        String user = "karaf";
        String password = "karaf";

        SshClient client = null;
        try {
            client = SshClient.setUpDefaultClient();
            client.start();
            ConnectFuture future = client.connect(host, port);
            future.await();
            ClientSession session = future.getSession();
            session.authPassword(user, password);
            ClientChannel channel = session.createChannel("shell");
            channel.setIn(System.in);
            channel.setOut(System.out);
            channel.setErr(System.err);
            channel.open();
            channel.waitFor(ClientChannel.CLOSED, 0);
        } catch (Throwable t) {
            t.printStackTrace();
            System.exit(1);
        } finally {
            try {
                client.stop();
            } catch (Throwable t) { }
        }
        System.exit(0);
    }

}

You can find a more complete example at the following location.

#top

6.2. Custom distributions

6. Advanced uses

6.4. Embedding Karaf

6.3. Programmatically connect to the console

6. Advanced uses

6.5. Deploying security providers

6.4. Embedding Karaf

TODO: an example of embedding Karaf inside a web application is provided in the distribution

#top

6.3. Programmatically connect to the console

6. Advanced uses

6.5. Deploying security providers

6.4. Embedding Karaf

6. Advanced uses

6.6. Installing additional features

6.5. Deploying security providers

Some applications require specific security providers to be available, such as BouncyCastle. The JVM impose 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 require you to configure all your servers accordingly.

Karaf offers a simple way to configure additional security providers:

• put your provider jar in [FELIX:KARAF]/lib
• modify the [FELIX:KARAF]/etc/config.properties configuration file to add the following property

org.apache.felix.karaf.security.providers = xxx,yyy

The value of this property is a comma separated list of the provider class names to register.
For example:

org.apache.felix.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*

#top

6.4. Embedding Karaf

6. Advanced uses

6.6. Installing additional features

6.5. Deploying security providers

6. Advanced uses

6.7. Configuring Failover Deployments

6.6. Installing additional features

This chapter will demonstrate how to add additional features from a remote maven repository to a default installation of Karaf.

Adding additional maven repositories

The following steps will add in the missing OPS4J and Apache Snapshot maven repositories. Note - this has been fixed in the 1.1.0 of ServiceMix Kernel release and can be skipped.

1. Edit the following file -

   etc/org.ops4j.pax.url.mvn.cfg
   

2. Update org.ops4j.pax.url.mvn.repositories to include the OPS4J and Apache Snapshot repos -

   org.ops4j.pax.url.mvn.repositories=file:${user.home}/.m2/repository@snapshots,http://repo1.maven.org/maven2,http://repository.ops4j.org/maven2,http://people.apache.org/repo/m2-snapshot-repository<at:var at:name="snapshots" />noreleases
   

Adding additional feature repositories

The following steps will add in the URLs for the Camel & ActiveMQ and Features locations.

1. Start Karaf

   cd bin
   ./karaf or karaf.bat
   

2. Add the following feature install locations

   karaf@root> features:addUrl mvn:org.apache.activemq/activemq-karaf/5.4.0/xml/features
   karaf@root> features:addUrl mvn:org.apache.camel.karaf/features/2.0.0/xml/features
   
   

3. Verify the feature URLs were added -

   karaf@root> features:listUrl
   mvn:org.apache.camel.karaf/features/2.0.0/xml/features    valid
   mvn:org.apache.activemq/activemq-karaf/5.4.0/xml/features    valid
   mvn:org.apache.karaf/apache-karaf/2.0.1-SNAPSHOT/xml/features    valid
   

Installing a new feature (war)

The following steps will install the "war" feature (support for deploying WAR files with Servlet and JSPs into a Jetty server) into your Karaf instance.

1. List the available features -

   karaf@root> features:list
    State        Name
   . . .
   [uninstalled] [2.0.0] obr                      karaf-2.0.0
   [uninstalled] [2.0.0] config                   karaf-2.0.0
   [uninstalled] [2.0.0] http                     karaf-2.0.0
   [uninstalled] [2.0.0] war                      karaf-2.0.0
   [uninstalled] [2.0.0] webconsole               karaf-2.0.0
   [installed  ] [2.0.0] ssh                      karaf-2.0.0
   
   . . .
   

2. Install the war feature (and the sub-features it requires) -

   karaf@root> features:install war
   

3. Verify the features were installed

   karaf@root> features:list
    State        Name
   . . .
   [installed  ] [2.0.0] http                     karaf-2.0.0
   [installed  ] [2.0.0] war                      karaf-2.0.0
   . . .
   

4. Verify the installed bundles were started

   karaf@root> osgi:list
   START LEVEL 100
      ID   State         Blueprint      Level  Name
   . . .
   [  32] [Active     ] [            ] [   60] geronimo-servlet_2.5_spec (1.1.2)
   [  33] [Active     ] [            ] [   60] Apache ServiceMix :: Bundles :: jetty (6.1.22.2)
   [  34] [Active     ] [            ] [   60] OPS4J Pax Web - API (0.7.2)
   [  35] [Active     ] [            ] [   60] OPS4J Pax Web - Service SPI (0.7.2)
   [  36] [Active     ] [            ] [   60] OPS4J Pax Web - Runtime (0.7.2)
   [  37] [Active     ] [            ] [   60] OPS4J Pax Web - Jetty (0.7.2)
   [  38] [Active     ] [            ] [   60] OPS4J Pax Web - Jsp Support (0.7.2)
   [  39] [Active     ] [            ] [   60] OPS4J Pax Web - Extender - WAR (0.7.2)
   [  40] [Active     ] [            ] [   60] OPS4J Pax Web - Extender - Whiteboard (0.7.2)
   [  41] [Active     ] [            ] [   60] OPS4J Pax Url - war:, war-i: (1.1.3)
   [  42] [Active     ] [Created     ] [   60] Apache Karaf :: WAR Deployer (2.0.0)
   . . .
   

5. The Jetty server should now be listening on http://localhost:8181/, but with no published applications available.

   HTTP ERROR: 404
   NOT_FOUND
   RequestURI=/
   Powered by jetty://
   

Deploying a WAR to the installed web feature

The following steps will describe how to install a simple WAR file (with JSPs or Servlets) to the just installed web feature.

1. To deploy a WAR (JSP or Servlet) to Jetty, update its MANIFEST.MF to include the required OSGi headers as described here -
   http://wiki.ops4j.org/confluence/display/ops4j/Pax+Web+Extender+-+War+-+OSGi-fy
2. Copy the updated WAR (archive or extracted files) to the deploy directory.

#top

6.5. Deploying security providers

6. Advanced uses

6.7. Configuring Failover Deployments

top

6.7. Configuring Failover Deployments

This chapter will demonstrate how to configure failover deployments.

Simple lock file

The simple lock file mechanism is intended for failover configurations where instances reside on the same host machine.

To use this feature, edit the $KARAF_HOME/etc/system.properties file as follows on each system in the master/slave setup:

Note: Ensure that the karaf.lock.dir property points to the same directory for both the master and slave instance, so that the slave can only acquire the lock when the master releases it.

JDBC locking

The JDBC locking mechanism is intended for failover configurations where instances exist on separate machines. In this deployment, the master instance holds a lock on a Karaf locking table hosted on a database. If the master loses the lock, a waiting slave process gains access to the locking table and fully starts its container.

To use this feature, do the following on each system in the master/slave setup:

• Update the classpath to include the JDBC driver
• Update the $KARAF_HOME/bin/karaf script to have unique JMX remote port set if instances reside on the same host
• Update the $KARAF_HOME/etc/system.properties file as follows:

Note:

• Will fail if JDBC driver is not on classpath.
• The database name "sample" will be created if it does not exist on the database.
• The first Karaf instance to acquire the locking table is the master instance.
• If the connection to the database is lost, the master instance tries to gracefully shutdown, allowing a slave instance to become master when the database service is restored. The former master will require manual restart.

JDBC locking on Oracle

If you are using Oracle as your database in a JDBC locking scenario, the karaf.lock.class property in the $KARAF_HOME/etc/system.properties file must point to org.apache.felix.karaf.main.OracleJDBCLock.

Otherwise, configure the system.properties file as normal for your setup, for example:

As with the default JDBC locking setup, the Oracle JDBC driver JAR file must be in your classpath. You can ensure this by copying the ojdbc14.jar into Karaf's lib folder before starting Karaf.

Note: The karaf.lock.jdbc.url requires an active SID, which means you must manually create a database instance before using this particular lock.

locklevel

Container-level locking

Container-level locking allows bundles to be preloaded into the slave kernel instance in order to provide faster failover performance. Container-level locking is supported in both the simple file and JDBC locking mechanisms.

To implement container-level locking, add the following to the $KARAF_HOME/etc/system.properties file on each system in the master/slave setup:

The karaf.log.level property tells the Karaf instance how far up the boot process to bring the OSGi container. Bundles assigned the same start level or lower will then also be started in that Karaf instance.

Bundle start levels are specified in $KARAF_HOME/etc/startup.properties, in the format jar.name=level. The core system bundles have levels below 50, where as user bundles have levels greater than 50.

Note: When using a 'hot' spare on the same host you need to set the JMX remote port to a unique value to avoid bind conflicts. You can edit the Karaf start script to include the following:

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6. Advanced uses

Karaf Users' Guide

7. Optional Features

• 7.1. Enabling Colorized Console Output On Windows

#top

6. Advanced uses

Karaf Users' Guide

7. Optional Features

7.1. Enabling Colorized Console Output On Windows

The default Karaf installation does not produce colorized console output on Windows like it does on Unix based systems. To enable it, you must install LGPL licensed library JNA. This can be done using a few simple commands in the Karaf console:

You first need to install the JNA library:

osgi:install wrap:mvn:http://download.java.net/maven/2!net.java.dev.jna/jna/3.1.0

Next you need either restart karaf or you run the following Karaf commands to refresh the Karaf Console:

osgi:list | grep "Apache Felix Karaf :: Shell Console"

Take note of the ID of the bundle, in my case it was 14 and then run:

osgi:refresh 14

#top

7. Optional Features