## Run gitlab-runner in a container

### Docker image installation and configuration

Install Docker first:

```bash
curl -sSL https://get.docker.com/ | sh
```

We need to mount a config volume into our gitlab-runner container to
be used for configs and other resources:

```bash
docker run -d --name gitlab-runner --restart always \
  -v /srv/gitlab-runner/config:/etc/gitlab-runner \
  gitlab/gitlab-runner:latest
```

OR you can use a config container to mount your custom data volume:

```bash
docker run -d --name gitlab-runner-config \
    -v /etc/gitlab-runner \
    busybox:latest \
    /bin/true

docker run -d --name gitlab-runner --restart always \
    --volumes-from gitlab-runner-config \
    gitlab/gitlab-runner:latest
```

If you plan on using Docker as the method of spawning runners, you will need to
mount your docker socket like this:

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

Register the runner:

```bash
docker exec -it gitlab-runner gitlab-runner register

Please enter the gitlab-ci coordinator URL (e.g. https://gitlab.com/ci )
https://gitlab.com/ci
Please enter the gitlab-ci token for this runner
xxx
Please enter the gitlab-ci description for this runner
my-runner
INFO[0034] fcf5c619 Registering runner... succeeded
Please enter the executor: shell, docker, docker-ssh, ssh?
docker
Please enter the Docker image (eg. ruby:2.1):
ruby:2.1
INFO[0037] Runner registered successfully. Feel free to start it, but if it's
running already the config should be automatically reloaded!
```

The runner should is started already and you are ready to build your projects!

### Update

Pull the latest version:

```bash
docker pull gitlab/gitlab-runner:latest
```

Stop and remove the existing container:

```bash
docker stop gitlab-runner && docker rm gitlab-runner
```

Start the container as you did originally:

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

**Note**: you need to use the same method for mounting you data volume as you
    did originally (`-v /srv/gitlab-runner/config:/etc/gitlab-runner` or `--volumes-from gitlab-runner`)

### Installing Trusted SSL Server Certificates

If your GitLab CI server is using self-signed SSL certificates then you should
make sure the GitLab CI server certificate is trusted by the gitlab-ci-multi-runner
container for them to be able to talk to each other.

The `gitlab/gitlab-runner` image is configured to look for the trusted SSL
certificates at `/etc/gitlab-runner/certs/ca.crt`, this can however be changed using the
`-e "CA_CERTIFICATES_PATH=/DIR/CERT"` configuration option.

Copy the `ca.crt` file into the `certs` directory on the data volume (or container).
The `ca.crt` file should contain the root certificates of all the servers you
want gitlab-ci-multi-runner to trust. The gitlab-ci-multi-runner container will
import the `ca.crt` file on startup so if your container is already running you
may need to restart it for the changes to take effect.

### Alpine Linux

You can also use alternative [Alpine Linux](https://www.alpinelinux.org/) based image with much smaller footprint:
```
gitlab/gitlab-runner    latest              3e8077e209f5        13 hours ago        304.3 MB
gitlab/gitlab-runner    alpine              7c431ac8f30f        13 hours ago        25.98 MB
```

**Alpine Linux image is designed to use only Docker as the method of spawning runners.** 

The original `gitlab/gitlab-runner:latest` is based on Ubuntu 14.04 LTS.