gitlab ci with docker runner

  • March 29, 2015

In my company we’re using Gitlab for managing our code and doing code review. For the last months we’ve been standardizing our stack on Symfony/Postgresql/php-fpm. Recently we’ve started automatizing our tests using phpunit. The next step was of course to have a start of continuous integration and to be able to run our tests at each Merge request.

In this article we’re going to view

  • How to install gitlab-ci on a separate server than your gitlab instance
  • How to put gitlab-ci behind your company frontal server
  • How to make gitlab-ci run your tests in a Docker container

Gitlab-CI in a separate instance

To do continous-integration you got plenty of choice, the most popular one being jenkinks. However it seems to be that it is a bit bloated and has too much feature that we don’t need for the moment.

On the other side gitlab comes with its own CI system (named Gitlab-ci) that has the advantage to be damn simple for the moment and of course pretty much integrated to gitlab (no need to create new accounts, build status directly in gitlab etc.)

In order to install it you can use the ommibus package which will take care of installing everything from you

Then in order to have only gitlab-ci you can can follow the step Running Gitlab on its own server

Gitlab-CI behind your company’s frontal server

Our company as one public IP under which we host all our services. We have then a frontal apache2 (but it could have been a nginx) which proxify then the request depending of the hostname. In that case it does not make sense for us to still have the Nginx that is installed with the omnibus package

So in order to deactivate it, in your /etc/gitlab/gitlab.rb in the Nginx section you can add

nginx['enable'] = false
ci_nginx['enable'] = false

and then

sudo gitlab-ctl reconfigure

then in your frontal you can put a vhost

<VirtualHost  *:80>
    ServerName gitlab-ci.example.com

    ProxyRequests off
    ProxyPreserveHost on
    ProxyPass / http://LAN_IP_OF_YOUR_GITLAB_CI:8181/
    ProxyPassReverse / http://LAN_IP_OF_YOUR_GITLAB_CI:8181/
</VirtualHost>

(by default gitlab-ci’s unicorn listen on port 8181)

Tell Gitlab-ci to run your test into a docker container

Gitlab-ci use what they call a “Runner” to run your test, it’s more or less a spare machine in which Gitlab-ci will clone your project and run a bash script you’ve provided in the Gitlab-ci admin panel

The goal of this article is not to do a deep introduction to Docker but basically it’s a powerful technology that permits you to run “containers”. You can consider a container as a virtual machine without the virtual part, and restricted to Linux. (more or less)

The container will brings their full advatanges with gitlab-ci as

  • they don’t take extra memory when not being runned
  • you can create a new container from a base image in a blink of eyes

Fortunately for us a Docker image already exists with all the base things to have a Gitlab-ci Runner in a container. The repository

If you have already docker installed you can pull the image doing

docker pull sameersbn/gitlab-ci-runner:latest

Then you need to register your runner to gitlab-ci you can do that with

mkdir -p /opt/your-project-runner
docker run --name your-project-runner -it --rm \
    -v /opt/your-project-runner:/home/gitlab_ci_runner/data \
  sameersbn/gitlab-ci-runner:latest app:setup

it will ask you some information given to you by your instance of gitlab-ci

you can then pop a runner by doing

docker run --name your-project-runner -it -d \
    -v /opt/your-project-runner:/home/gitlab_ci_runner/data \
  sameersbn/gitlab-ci-runner:latest app:setup

you will certainly to customize some stuff on your container you can do so by connecting as root to it using

docker exec -it your-project-runner bash

of course something to keep in mind is that container are meant to be stateless which mean that outside of the directories you map with -v option the other information will be deleted when you restart the container

So if you need to always create the same kind of container, you can create your own Runner container by extending this one to fit your needs, like it has been done in the docker image to run test for gitlab’s own source code

In a next article we will see in details how to create step by step your own Gitlab-ci for your php/symfony project

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