coderfi/jenkins-plus repository overview

⁠docker-jenkins-plus

Adds additional tools to the official jenkins docker.

i.e. Jenkins Docker building Dockers

• docker.io 1.5.0 build a8a31ef⁠

⁠quick start

Create a Volume Docker

docker run --name jenkins-data -v /var/jenkins_home busybox sh -c "mkdir -p /var/jenkins_home; chown 1000:1000 /var/jenkins_home"

Start Jenkins with docker support:

docker run -d --name jenkins -p 50000:50000 -e DOCKER_GID=`grep "^docker" /etc/group|cut -d: -f3` -p 8080:8080 -v /var/run/docker.sock:/var/run/docker.sock --volumes-from jenkins-data coderfi/jenkins-plus

The container will set the container's docker group id to the DOCKER_GID env. Be sure this matches the host's docker group id, otherwise the jenkins process will not have permission to run docker commands!

⁠browser

visit http://your_host:8080

⁠recommended Jenkins plugins

• Docker build step plugin⁠

• Docker build publish Plugin⁠

⁠see also

• Official Jenkins Docker⁠

• Official Jenkins Docker Github⁠

⁠about the build

I wanted to build docker images via Jenkins on a CoreOS host OS.

I quickly found the official Jenkins docker to accomplish this, however, I also quickly found out that the docker package was lacking from this image.

In order to run docker commands, we mount the host's /var/run/docker.sock volume.

To run a docker command, the user must either be root, or be part of the docker group.

The official Jenkins docker sets the default User to be jenkins.

As you can see from the Dockerfile, we add the jenkins user to the docker group.

Unfortunately, the docker's docker group is not the same as the host's docker group.

So, what we do is hack the docker's docker group id to match the host's docker group id, which is specified by the DOCKER_GID environment variable.

Problem solved!

Now I can deploy a Jenkins master node running inside a docker container on my CoreOS installation, and use Jenkins as part of my Continuous Integration strategy building other dockers.