Auto-scale CI jobs with Gitlab Runner and the Hetzner Docker Machine driver

With this patched GitLab Runner image, you can auto-scale your CI jobs on Hetzner Cloud. The patch installs the Hetzner Docker Machine driver and is available on Docker Hub.

You can follow the official GitLab docs for configuring the GitLab Runner with docker machine, just use this image as a drop in replacement for gitlab/gitlab-runner.

See the example config.toml and docker-compose.yaml below for the hetzner specific docker machine options.

To publish a new version

1. Open Dockerfile, adjust the base version number.
2. Open .github/workflows/docker-build.yml and look for the previous version number occurences and replace by the new one.
3. Push on master, let Actions publish the image on Dockerhub.

Usage

Use this image instead of the gitlab/gitlab-runner image and set MachineDriver to hetzner in your runner configuration.

Example config.toml:

concurrent = 1
check_interval = 0

[session_server]
  session_timeout = 1800

[[runners]]
  name = "docker-machine"
  url = "https://gitlab.com"
  token = "your-token"
  executor = "docker+machine"
  [runners.docker]
    tls_verify = false
    image = "docker:latest"
    privileged = true
    disable_cache = false
    volumes = ["/cache"]
    shm_size = 536870912
  [runners.cache]
  [runners.machine]
    IdleCount = 0
    IdleTime = 1800
    MaxBuilds = 10
    MachineDriver = "hetzner"
    MachineName = "runner-%s"
    MachineOptions = [
      "hetzner-api-token=hetzner-api-token",
      "hetzner-image=ubuntu-18.04",
      "hetzner-server-type=cx31",
    ]

Example docker-compose.yaml:

version: "3.8"

services:
  hetzner-runner:
    image: mawalu/hetzner-gitlab-runner:latest
    volumes:
      - "./hetzner_config:/etc/gitlab-runner"

Docker Errors

If you face docker problems at runtime (such as the one below), you can specify a Docker version in the MachineOptions.

 MachineOptions = [
      "engine-install-url=https://releases.rancher.com/install-docker/19.03.9.sh",
    ]

Possible error that is caused by Docker:

ERROR: Error creating machine: Error running provisioning: Unable to verify the Docker daemon is listening: Maximum number of retries (10) exceeded  driver=hetzner name=runner-xxx-xxx operation=create

See this issue for more information.

Versions

Currently this image is build using the gitlab/gitlab-runner:latest image and the latest docker-machine hetzner plugin. If you need builds for another version feel free to open an PR.

License

MIT