In the first part of this series we got a Docker Swarm running with Vagrant and CoreOS. In this part we are going to use this Docker Swarm to run a Jenkins 2.0 installation. Jenkins is a continous delivery tool. You can configure jobs to build your projects and deploy them. There are plugins for many build environments available.

After my initial tests with Sharing Volumes with docker-swarm based on Docker 1.11 I still had some open issues. This docker-swarm was no transparent replacement for a plain Docker host. The main problem was sharing data between containers on different swarm nodes. Some quick tests with the integrated swarm mode for Docker 1.12 showed, that this new mode takes an different approach than the docker-swarm containers before. You need to create special services to utilize it. It doesn’t seem to solve the problem with sharing volumes between hosts though and does not work with docker-compose yet.

The coreos-vagrant Template is a minimal template to get a coreos cluster with Docker running. Docker is exposed via tcp/2375. This is an unsecured http connection. That is fine for trusted test environments. But for production systems and untrusted environments, it is necessary to secure this connection via transport layer security (TLS). Docker supports TLS out of the box. We just need to create keys and change the configuration.

While trying to get Jenkins to run in a docker-swarm installation I had some problems to share volumes between containers. Usually, you can just define a data-only container and import volumes from this into other containers. Starting with docker 1.9 you do not even need to create a data-only container, but can just use named volumes.

In this post i will show you how to setup a multi node jenkins cluster running in a docker-swarm on coreos. In part 1 we will get a docker-swarm enabled cluster running. In part 2 we will use this docker-swarm to run jenkins.