How do I get a Docker Gitlab CI runner to access Git on its parent host?

Question

Gitlab is setup on our internal network at http://gitlab

Docker containers on the same machine can't connect to it.

How do I configure docker so that it knows gitlab is its parent?

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The problem exhibits itself when Gitlab CI attempts to run a build (inside a Docker container):

Cloning into '/builds/ns/project'... fatal: unable to access 'http://gitlab-ci-token:xxxxxx@gitlab/ns/project.git/': Couldn't resolve host 'gitlab'

I've tried adding the network's DNS servers to DOCKER_OPTS in /etc/default/docker to no avail.

Answer 1

According to the GitLab CI Runner Advanced configuration, you can try to play with the extra_hosts param in your GitLab CI runner. In /etc/gitlab-runner/config.toml :

[[runners]]
  url = "http://gitlab/ci"
  token = "TOKEN"
  name = "my_runner"
  executor = "docker"
  [runners.docker]
    host = "tcp://<DOCKER_DAEMON_IP>:2375"
    image = "..."
    ...
    extra_hosts = ["gitlab:192.168.0.39"]

With this example, when inside the container running the test git will try to clone from gitlab, it will use the 192.168.0.39 as IP for this hostname.