6.2. Custom distributions

As Karaf is an OSGi container, it's heavily used as the kernel of applications and middlewares.

You could require to construct your own Karaf distribution matching your requirements.
This custom distribution could contain:

configuration files that you want to change by default (in the etc folder)
pre-packaged artifacts in the deploy folder
pre-populated system repository (containing your own bundle and features descriptor)
renamed or specific scripts in the bin folder
branding
your documentation files

Maven assembly

Basically a Karaf custom distribution is:
1. Uncompressing a standard Karaf distribution in a given directory.
2. Populating the system repo with your features.
3. Populating the lib directory with your branding or other system bundle jar files.
4. Overriding the configuration files in the etc folder.

These tasks could be performed using scripting, or more easily and portable, using Apache Maven and a set of Maven plugins.

For instance, the Maven POM could look like:

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <groupId>my.company</groupId> <artifactId>mycustom-karaf</artifactId> <version>1.0</version> <packaging>pom</packaging> <name>My Unix Custom Karaf Distribution</name> <properties> <karaf.version>2.1.3</karaf.version> </properties> <dependencies> <dependency> <groupId>org.apache.karaf</groupId> <artifactId>apache-karaf</artifactId> <version>${karaf.version}</version> <type>tar.gz</type> </dependency> <dependency> <groupId>org.apache.karaf</groupId> <artifactId>apache-karaf</artifactId> <version>${karaf.version}</version> <type>xml</type> <classifier>features</classifier> </dependency> </dependencies> <build> <resources> <resource> <directory>${project.basedir}/src/main/filtered-resources</directory> <filtering>true</filtering> <includes> <include>**/*</include> </includes> </resource> </resources> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-resources-plugin</artifactId> <executions> <execution> <id>filter</id> <phase>generate-resources</phase> <goals> <goal>resources</goal> </goals> </execution> </executions> </plugin> <plugin> <groupId>org.apache.karaf.tooling</groupId> <artifactId>features-maven-plugin</artifactId> <version>${karaf.version}</version> <executions> <execution> <id>add-features-to-repo</id> <phase>generate-resources</phase> <goals> <goal>add-features-to-repo</goal> </goals> <configuration> <descriptors> <descriptor>mvn:org.apache.karaf/apache-karaf/${karaf.version}/xml/features</descriptor> <descriptor>file:${project.basedir}/target/classes/my-features.xml</descriptor> </descriptors> <features> <feature>my-feature</feature> </features> </configuration> </execution> </executions> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-dependency-plugin</artifactId> <executions> <execution> <id>copy</id> <phase>generate-resources</phase> <goals> <goal>copy</goal> </goals> <configuration>   <artifactItems> <artifactItem> <groupId>my.groupId</groupId> <artifactId>my.branding.id</artifactId> <version>1.0</version> <outputDirectory>target/dependencies</outputDirectory> <destFileName>mybranding.jar</destFileName> </artifactItem> </artifactItems> </configuration> </execution> <execution>  <id>unpack</id> <phase>generate-resources</phase> <goals> <goal>unpack</goal> </goals> <configuration> <artifactItems> <artifactItem> <groupId>org.apache.karaf</groupId> <artifactId>apache-karaf</artifactId> <type>tar.gz</type> <outputDirectory>target/dependencies</outputDirectory> </artifactItem> </artifactItems> </configuration> </execution> </executions> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-assembly-plugin</artifactId> <executions> <execution> <id>bin</id> <phase>package</phase> <goals> <goal>single</goal> </goals> <configuration> <descriptors> <descriptor>src/main/descriptors/bin.xml</descriptor> </descriptors> <appendAssemblyId>false</appendAssemblyId> <tarLongFileMode>gnu</tarLongFileMode> </configuration> </execution> </executions> </plugin> </plugins> </build> </project>

The Maven POM will download the Karaf standard distribution and prepares resources to be processed by the Maven assembly plugin.

Your Maven project structure should look like:

pom.xml: the previous POM file
src/main/descriptors/bin.xml: the assembly maven plugin descriptor (see below)
src/main/filtered-resources: contains all files where some maven properties should be replaced/filtered. Typically, it contains the features descriptor and configuration files.
src/main/distribution: contains all raw files which will be copied into your custom distribution.

For instance, src/main/filtered-resources could contains:

my-features.xml where maven properties will be replaced
etc/org.apache.karaf.features.cfg file containing your my-features descriptor: # # Comma separated list of features repositories to register by default # featuresRepositories=mvn:org.apache.karaf/apache-karaf/${karaf.version}/xml/features,mvn:my.groupId/my-features/${project.version}/xml/features # # Comma separated list of features to install at startup # featuresBoot=config,ssh,management,my-feature

The src/main/distribution contain all your custom Karaf configuration files and script, as, for examples:

etc/org.ops4j.pax.logging.cfg # Root logger log4j.rootLogger=INFO, out, osgi:VmLogAppender 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{ABSOLUTE} | %-5.5p | %-16.16t | %-32.32C %4L | %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{ABSOLUTE} | %-5.5p | %-16.16t | %-32.32C %4L | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %m%n log4j.appender.out.file=${karaf.home}/log/my-customer-distribution.log log4j.appender.out.append=true log4j.appender.out.maxFileSize=1MB log4j.appender.out.maxBackupIndex=10 # Sift appender log4j.appender.sift=org.apache.log4j.sift.MDCSiftingAppender log4j.appender.sift.key=bundle.name log4j.appender.sift.default=my-custom log4j.appender.sift.appender=org.apache.log4j.FileAppender log4j.appender.sift.appender.layout=org.apache.log4j.PatternLayout log4j.appender.sift.appender.layout.ConversionPattern=%d{ABSOLUTE} | %-5.5p | %-16.16t | %-32.32c{1} | %-32.32C %4L | %m%n log4j.appender.sift.appender.file=${karaf.data}/log/$\\{bundle.name\\}.log log4j.appender.sift.appender.append=true
etc/system.properties # # The properties defined in this file will be made available through system # properties at the very beginning of the FAS boot process. # # Log level when the pax-logging service is not available # This level will only be used while the pax-logging service bundle # is not fully available. # To change log levels, please refer to the org.ops4j.pax.logging.cfg file # instead. org.ops4j.pax.logging.DefaultServiceLog.level=ERROR # # Name of this custom instance. # karaf.name=my-custom # # Default repository where bundles will be loaded from before using # other maven repositories. For the full maven configuration, see the # org.ops4j.pax.url.mvn.cfg file. # karaf.default.repository=system # # Location of a shell script that will be run when starting a shell # session. This script can be used to create aliases and define # additional commands. # karaf.shell.init.script=${karaf.home}/etc/shell.init.script # # Set this empty property to avoid errors when validating xml documents. # xml.catalog.files= # # Suppress the bell in the console when hitting backspace to many times # for example # jline.nobell=true # # Default port for the OSGi HTTP Service # org.osgi.service.http.port=8181 # # Allow usage of ${custom.home} as an alias for ${karaf.home} # custom.home=${karaf.home}
etc/users.properties admin=admin,admin

Now, we can "assemble" our custom distribution using the Maven assembly plugin. The Maven assembly plugin uses an assembly descriptor in the src/main/descriptors/bin.xml:

<assembly> <id>bin</id> <formats> <format>tar.gz</format> </formats> <fileSets>  <fileSet> <directory>target/dependencies/apache-karaf-${karaf.version}</directory> <outputDirectory>/</outputDirectory> <excludes> <exclude>**/demos/**</exclude> <exclude>bin/**</exclude> <exclude>etc/system.properties</exclude> <exclude>etc/users.properties</exclude> <exclude>etc/org.apache.karaf.features.cfg</exclude> <exclude>etc/org.ops4j.pax.logging.cfg</exclude> <exclude>LICENSE</exclude> <exclude>NOTICE</exclude> <exclude>README</exclude> <exclude>RELEASE-NOTES</exclude> <exclude>karaf-manual*.html</exclude> <exclude>karaf-manual*.pdf</exclude> </excludes> </fileSet>  <fileSet> <directory>target/dependencies/apache-karaf-${karaf.version}</directory> <outputDirectory>/</outputDirectory> <includes> <include>bin/admin</include> <include>bin/karaf</include> <include>bin/start</include> <include>bin/stop</include> </includes> <fileMode>0755</fileMode> </fileSet>  <fileSet> <directory>target/dependencies</directory> <includes> <include>my-custom.jar</include> </includes> <outputDirectory>/lib/</outputDirectory> </fileSet> <fileSet> <directory>src/main/distribution</directory> <outputDirectory>/</outputDirectory> <fileMode>0644</fileMode> </fileSet> <fileSet> <directory>target/classes/etc</directory> <outputDirectory>/etc/</outputDirectory> <lineEnding>unix</lineEnding> <fileMode>0644</fileMode> </fileSet> <fileSet> <directory>target/features-repo</directory> <outputDirectory>/system</outputDirectory> </fileSet> </fileSets> <files> <file> <source>${basedir}/target/dependencies/apache-karaf-${karaf.version}/bin/karaf</source> <outputDirectory>/bin/</outputDirectory> <destName>my-custom</destName> <fileMode>0755</fileMode> <lineEnding>unix</lineEnding> </file> <file> <source>${basedir}/target/classes/features.xml</source> <outputDirectory>/system/my.groupid/my-features/${project.version}</outputDirectory> <destName>my-features-${project.version}-features.xml</destName> <fileMode>0644</fileMode> <lineEnding>unix</lineEnding> </file> </files> </assembly>

To build you custom Karaf distribution, just do:

mvn install

You will find your Karaf custom distribution tar.gz in the target directory.

Roadmap

A distribution goal is in preparation in the next Karaf

Custom distribution examples

#top

{scrollbar}