This Dockerfile builds a dockerimage based on debian:stretch including all requirements to build Elektra and most of its bindings/plugins to act as a build node for Jenkins. It contains an ssh server and a java environment to allow jenkins to connect to the container and execute commands on top of that.

Before building the image, you may want to adjust the password for jenkins to something more secure, so adjust the line echo "jenkins:<password>" | chpasswd && \ in the Dockerfile.

Optionally you can modify the file run_make if you want to increase the number of jobs for the make command on the build container. You can also modify run_ionice to adjust the build process' priority, which is set to idle by default in order to keep the host system responsive. In case you want to disable that, change the line ionice -c 3 nice $* in run_ionice to simply $*.

Now build the image with the following command:

$ docker build -t buildelektra-stretch .

After the build process has completed you can create and run a Docker container that uses the image we just created. Additionally you need to forward the ssh port to some port you want to use on the container's host so jenkins can connect to it. We give this container a name to easily refer to it at runtime.

$ docker run -d -p 22222:22 --name build-v2 buildelektra-stretch

Now you should be able to connect to the container locally via the host machine:

$ ssh jenkins@localhost -p 22222

Afterwards you need to ensure that this ssh port is also accessible from the outside, so that the jenkins master server can connect to the build node. As this greatly depends on the given network setup we can't give an exact explanation for it, but you may need to expose the local port to the outside or even use SSH tunneling or forwarding in case your build node doesn't have direct access to the jenkins master server.

Once this works, you have to add the credentials for the container's jenkins user to the main jenkins server and connect to it. All done!