Karaf Docker image

Supported tags and respective Dockerfile links

• 4.0.10, 4.0 (4.0/Dockerfile)
• 4.0.10-alpine, 4.0-alpine (4.0-alpine/Dockerfile)
• 4.1.5, 4.1, 4, latest (4.1/Dockerfile)
• 4.1.5-alpine, 4.1-alpine, 4-alpine (4.1-alpine/Dockerfile)

What is Karaf

Apache Karaf is a modern and polymorphic container powered by OSGi. Karaf can be used standalone as a container, supporting a wide range of applications and technologies. It also supports the "run anywhere" (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.

Start a Karaf server instance

You can run container simply by

docker run --name some-karaf -d \
    -p 1099:1099 \
    -p 8101:8101 \
    -p 44444:44444 hlavki/karaf

The docker exec command allows you to run commands inside a Docker container. The following command line will give you a bash shell inside your karaf container:

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

The Karaf container log is available through Docker's container log:

docker logs -f some-karaf

Environment variables

When you start the karaf image, you can adjust the configuration of the Karaf instance by passing one or more environment variables on the docker run command line.

• JAVA_MIN_MEM - Minimum memory for the JVM
• JAVA_MAX_MEM - Maximum memory for the JVM
• JAVA_PERM_MEM - Minimum perm memory for the JVM
• JAVA_MAX_PERM_MEM - Maximum perm memory for the JVM
• EXTRA_JAVA_OPTS - Additional JVM options
• KARAF_DATA - Karaf data folder
• KARAF_OPTS - Additional available Karaf options
• KARAF_DEBUG - Enable debug mode
• KARAF_REDIRECT - Enable/set the std/err redirection when using bin/start
• KARAF_NOROOT - Prevent execution as root if set to true

Development

1. Hot deployment

You can map /deploy directory from host to container running:

docker run --name some-karaf -d \
    -p 1099:1099 \
    -p 8101:8101 \
    -p 44444:44444 \
    -v /host/path/deploy:/opt/karaf/deploy hlavki/karaf

2. Mapping local maven repository

You can map local maven repository instead of hot deployment. This image adds /opt/maven/repository directory to org.ops4j.pax.url.mvn.defaultRepositories so you can also redeploy bundles with snapshot version without restart. To run docker with this setup run:

docker run --name some-karaf -d \
    -p 1099:1099 \
    -p 8101:8101 \
    -p 44444:44444 \
    -v ~/.m2/repository:/opt/maven/repository hlavki/karaf

Where to store data

Karaf docker image doesn't create volume from data directory. So it means it's stored in container. It's automatically removed If you remove container. But if you need to have data folder persistent, you can create volume or named volume.

docker run --name some-karaf -v /opt/karaf/data -d hlavki/karaf