Let's create a GitLab Runner 🏃 in a docker container📦

Before your getting started, you can read the official documentation and don't read this article 😉

So, if you're still here, let's do it together!💪

1. Pull the GitLab Runner Docker Image: Open your terminal and run the following command to pull the GitLab Runner Docker image: docker pull gitlab/gitlab-runner:latest

2. Create new volume, it's a good practice to use a Docker volume to persist the config.toml file and ensure it remains available between container restarts. You can create a volume using: docker volume create gitlab-runner-config

3. Run the GitLab Runner Container:
   Next, run the GitLab Runner container. You can use the following command to start it in detached mode:

docker run -d --name yuit-gitlab-runner --restart always -v gitlab-runner-config:/etc/gitlab-runner -v /var/run/docker.sock:/var/run/docker.sock gitlab/gitlab-runner:latest


This command does the following:

• Runs the container in detached mode: -d.
• Names the container yuit-gitlab-runner.
• Restarts the runner automatically if it stops: --restart always.
• Maps the configuration directory via: -v gitlab-runner-config:/etc/gitlab-runner: This command mounts a Docker volume named gitlab-runner-config into the filesystem of the container at the specified path (/etc/gitlab-runner).
• Add docker socket: -v /var/run/docker.sock:/var/run/docker.sock: This command mounts the host's Docker socket file (/var/run/docker.sock) at the same location inside the container.

Explanation of Docker Socket: By mounting the Docker socket, the GitLab Runner can use Docker to run builds as containers. This is necessary for scenarios where your CI/CD pipelines leverage Docker as an executor for running jobs, allowing the GitLab Runner to create and manage Docker containers during the job execution.

Register runner in gitlab

• Select CI/CD > Runners.
• Select New instance runner.
• In the Tags section, in the Tags field, enter the job tags to specify jobs the runner can run. If there are no job tags for this runner, select Run untagged: yuit-runner-tag
• Runner description: Runner of docker container
• Select the operating system where GitLab Runner is installed: linux

Registering runners in local docker container

docker exec -it yuit-gitlab-runner gitlab-runner register
Enter the GitLab instance URL: https://gitlab.com
Enter the registration token: ****
Enter a name for the runner: yuit-runner
Enter an executor: docker
Enter the default Docker image: node:20.16-alpine