Gitlab-runner std

root@storage:/srv#    docker run -d --name gitlab-runner --restart always \
>      -v /srv/gitlab-runner/config:/etc/gitlab-runner \
>      -v /var/run/docker.sock:/var/run/docker.sock \
>      gitlab/gitlab-runner:latest
0ef3869a2a8394069cb00297b8004125b1c34ef9854a4326a40bc9225b0f438e

root@storage:/srv# docker run --rm -it -v /srv/gitlab-runner/config:/etc/gitlab-runner gitlab/gitlab-runner register
Runtime platform                                    arch=amd64 os=linux pid=8 revision=54944146 version=13.10.0
Running in system-mode.
 
Enter the GitLab instance URL (for example, https://gitlab.com/):
https://gitlab.oowy.fr
Enter the registration token:
drJDdsg2Px3LdBXNK29d
Enter a description for the runner:
[0fbcd90e5f3a]: gitlab-runner
Enter tags for the runner (comma-separated):
 
Registering runner... succeeded                     runner=drJDdsg2
Enter an executor: virtualbox, docker+machine, docker-ssh+machine, kubernetes, custom, docker, docker-ssh, parallels, shell, ssh:
docker
 
Enter the default Docker image (for example, ruby:2.6):
ruby:2.6
Runner registered successfully. Feel free to start it, but if it's running already the config should be automatically reloaded!

Gitlab-runner docker

# docker run -d --name gitlab-docker --restart always \
>       -v /srv/gitlab-docker/config:/etc/gitlab-runner \
>       -v /var/run/docker.sock:/var/run/docker.sock \
>       gitlab/gitlab-runner:latest
ee8195b8ddfc1aff042fcc4df8207ad332bb7049acfc98e7beb7aa44b64d06a5

# docker run --rm -it -v /srv/gitlab-docker/config:/etc/gitlab-runner gitlab/gitlab-runner register
Runtime platform                                    arch=amd64 os=linux pid=7 revision=54944146 version=13.10.0
Running in system-mode.
 
Enter the GitLab instance URL (for example, https://gitlab.com/):
https://gitlab.oowy.fr
Enter the registration token:
drJDdsg2Px3LdBXNK29d
Enter a description for the runner:
[05a2d788c211]: gitlab-docker
Enter tags for the runner (comma-separated):
 
Registering runner... succeeded                     runner=drJDdsg2
Enter an executor: ssh, virtualbox, docker+machine, docker-ssh+machine, docker, docker-ssh, parallels, shell, kubernetes, custom:
docker
Enter the default Docker image (for example, ruby:2.6):
docker:stable
Runner registered successfully. Feel free to start it, but if it's running already the config should be automatically reloaded!

# docker ps -a
CONTAINER ID   IMAGE                         COMMAND                  CREATED              STATUS              PORTS     NAMES
ee8195b8ddfc   gitlab/gitlab-runner:latest   "/usr/bin/dumb-init …"   About a minute ago   Up About a minute             gitlab-docker
0ef3869a2a83   gitlab/gitlab-runner:latest   "/usr/bin/dumb-init …"   4 minutes ago        Up 4 minutes                  gitlab-runner

# nano /srv/gitlab-docker/config/config.toml
concurrent = 1
check_interval = 0
 
[session_server]
  session_timeout = 1800
 
[[runners]]
  name = "gitlab-docker"
  url = "https://gitlab.oowy.fr"
  token = "xAragCD5KRvmJysjYrFn"
  executor = "docker"
  [runners.custom_build_dir]
  [runners.cache]
    [runners.cache.s3]
    [runners.cache.gcs]
    [runners.cache.azure]
  [runners.docker]
    tls_verify = false
    image = "docker:stable"
    privileged = false
    disable_entrypoint_overwrite = false
    oom_kill_disable = false
    disable_cache = false
    volumes = ["/var/run/docker.sock:/var/run/docker.sock", "/cache"]
    shm_size = 0

# docker restart gitlab-docker
gitlab-docker

# docker ps -a
CONTAINER ID   IMAGE                         COMMAND                  CREATED          STATUS          PORTS     NAMES
ee8195b8ddfc   gitlab/gitlab-runner:latest   "/usr/bin/dumb-init …"   17 minutes ago   Up 13 minutes             gitlab-docker
0ef3869a2a83   gitlab/gitlab-runner:latest   "/usr/bin/dumb-init …"   20 minutes ago   Up 20 minutes             gitlab-runner

Troubleshooting

Problem: In your GitLab CI jobs, you see this error message while trying to run some docker command:

error during connect: Post http://docker:2375/v1.40/auth: dial tcp: lookup docker on 192.168.178.1:53: no such host

Solution: This error occurs with docker-based gitlab runners such as the one we’re that are configured using a docker executor. The error message means that the inner docker container doesn’t have a connection to the host docker daemon.

In order to fix this, set these options in [runners.docker] in your gitlab-runner config.toml:

privileged = true
volumes = ["/cache", "/var/run/docker.sock:/var/run/docker.sock"]

Why this works Adding “/var/run/docker.sock:/var/run/docker.sock” allows the inner docker container running inside the gitlab-runner to access the outer (host) docker daemon. Without this, it tries to connect to the docker default URL, i.e. http://docker:2375. This URL can’t be resolved via DNS (the DNS server in my case is 192.168.178.1, the DNS standard port being 53), hence docker prints the error message listed above.