spalarus/karaf repository overview

Docker image for Karaf⁠ based on CentOS⁠ and OpenJDK 11⁠.

⁠Source Repository

@see on GitHub⁠

⁠Usage

Run Karaf in foreground:

docker run --rm -it spalarus/karaf /opt/karaf/bin/karaf

⁠Exposed Ports

• 1099 (rmi registry)
• 8101 (ssh)
• 8181 (jetty)
• 44444 (rmi server)

⁠Feature installation while container creation - delivered by VAR

Following command creates a karaf-container with features scr and webconsole.

docker run --rm -it -e KARAF_INIT_COMMANDS="feature:install scr; feature:install webconsole;" spalarus/karaf /opt/karaf/bin/karaf

After container-start a background process connects to karaf instance and invokes the commands defined in variable KARAF_INIT_COMMANDS. The installation process starts 10 seconds after container creation.

⁠Volume ( container:/opt/karaf/vol )

• ./etc (persistent storage for configuration files - see section 'Persistent configuration files')
• ./deploy (karaf deployment storage)
• ./log (directory for log files)
• ./tmp (directory for tmp files)
• ./bin (directory for initcommands-file)

docker run --rm -it -v /home/karaf/volume:/opt/karaf/vol spalarus/karaf /opt/karaf/bin/karaf

⁠Feature installation while container creation - delivered in file

The karaf commands for feature installation can provided in file /bin/initcommands. The installation process starts 10 seconds after container creation.

echo "feature:install scr; feature:install webconsole;" > /home/karaf/volume/bin/initcommands
docker run --rm -it -v /home/karaf/volume:/opt/karaf/vol spalarus/karaf /opt/karaf/bin/karaf

The script does not continue, if one of karaf-shell-script-commands fails!

⁠Background Karaf Container

docker run -d --name karaffe -v /home/karaf/volume:/opt/karaf/vol spalarus/karaf

⁠Connect to shell of running karaf container (named karaffe)

docker exec -it karaffe /opt/karaf/bin/client

⁠Persistent configuration files

Configuration files can move to volume. File updates survive container recreation, if volume directory is mounted to host.

An Example: To persist the file user.properties use following command:

docker exec -it karaffe /opt/karaf/bin/touchvoletc users.properties

The command above copies this file user.properties into the volume directory and creates a soft link from etc directory to vol directory.

It is possible to provide configuration files in /etc/ manually. On container recreation or container restart a script checks this directory and links the newly provided configuration files. To invoke this check in running karaf container on demand, please use following command:

docker exec -it karaffe /opt/karaf/bin/checkvoletc

⁠FAQ

• On SELinux secured systems (RHEL/CentOS) mount the volume with Z-Option (docker run -d --name karaffe -v /home/karaf/volume:/opt/karaf/vol:Z spalarus/karaf)
• This Karaf-container may have startup problems on Docker systems with CAP_SETUID capability restrictions. To run this container as root-user could be a workaround (docker run ... -u root ... spalarus/karaf )