• Pre-configure Docker container
  • Run GitLab on a public IP address
• Expose GitLab on different ports
• Configure multiple database connections
• Recommended next steps

Configure GitLab running in a Docker container

This container uses the official Linux package, so all configuration is done in the unique configuration file /etc/gitlab/gitlab.rb.

To access the GitLab configuration file, you can start a shell session in the context of a running container. This will allow you to browse all directories and use your favorite text editor:

sudo docker exec -it gitlab /bin/bash

You can also just edit /etc/gitlab/gitlab.rb:

sudo docker exec -it gitlab editor /etc/gitlab/gitlab.rb

Once you open /etc/gitlab/gitlab.rb make sure to set the external_url to point to a valid URL.

To receive emails from GitLab you have to configure the SMTP settings because the GitLab Docker image doesn’t have an SMTP server installed. You may also be interested in enabling HTTPS.

After you make all the changes you want, you will need to restart the container to reconfigure GitLab:

sudo docker restart gitlab

GitLab will reconfigure itself whenever the container starts. For more options about configuring GitLab, check the configuration documentation.

Pre-configure Docker container

You can pre-configure the GitLab Docker image by adding the environment variable GITLAB_OMNIBUS_CONFIG to Docker run command. This variable can contain any gitlab.rb setting and is evaluated before the loading of the container’s gitlab.rb file. This behavior allows you to configure the external GitLab URL, and make database configuration or any other option from the Linux package template. The settings contained in GITLAB_OMNIBUS_CONFIG aren’t written to the gitlab.rb configuration file, and are evaluated on load. To provide multiple settings, separate them with a colon (;).

Here’s an example that sets the external URL, enables LFS, and starts the container with a minimal shm size required for Prometheus:

sudo docker run --detach \
  --hostname gitlab.example.com \
  --env GITLAB_OMNIBUS_CONFIG="external_url 'http://gitlab.example.com'; gitlab_rails['lfs_enabled'] = true;" \
  --publish 443:443 --publish 80:80 --publish 22:22 \
  --name gitlab \
  --restart always \
  --volume $GITLAB_HOME/config:/etc/gitlab \
  --volume $GITLAB_HOME/logs:/var/log/gitlab \
  --volume $GITLAB_HOME/data:/var/opt/gitlab \
  --shm-size 256m \
  gitlab/gitlab-ee:<version>-ee.0

Every time you execute a docker run command, you need to provide the GITLAB_OMNIBUS_CONFIG option. The content of GITLAB_OMNIBUS_CONFIG is not preserved between subsequent runs.

Run GitLab on a public IP address

You can make Docker to use your IP address and forward all traffic to the GitLab container by modifying the --publish flag.

To expose GitLab on IP 198.51.100.1:

sudo docker run --detach \
  --hostname gitlab.example.com \
  --env GITLAB_OMNIBUS_CONFIG="external_url 'http://gitlab.example.com'" \
  --publish 198.51.100.1:443:443 \
  --publish 198.51.100.1:80:80 \
  --publish 198.51.100.1:22:22 \
  --name gitlab \
  --restart always \
  --volume $GITLAB_HOME/config:/etc/gitlab \
  --volume $GITLAB_HOME/logs:/var/log/gitlab \
  --volume $GITLAB_HOME/data:/var/opt/gitlab \
  --shm-size 256m \
  gitlab/gitlab-ee:<version>-ee.0

You can then access your GitLab instance at http://198.51.100.1/ and https://198.51.100.1/.

Expose GitLab on different ports

GitLab will occupy some ports inside the container.

If you want to use a different host port than 80 (HTTP), 443 (HTTPS), or 22 (SSH), you need to add a separate --publish directive to the docker run command.

For example, to expose the web interface on the host’s port 8929, and the SSH service on port 2424:

1. Use the following docker run command:

   sudo docker run --detach \
     --hostname gitlab.example.com \
     --env GITLAB_OMNIBUS_CONFIG="external_url 'http://gitlab.example.com:8929'; gitlab_rails['gitlab_shell_ssh_port'] = 2424" \
     --publish 8929:8929 --publish 2424:22 \
     --name gitlab \
     --restart always \
     --volume $GITLAB_HOME/config:/etc/gitlab \
     --volume $GITLAB_HOME/logs:/var/log/gitlab \
     --volume $GITLAB_HOME/data:/var/opt/gitlab \
     --shm-size 256m \
     gitlab/gitlab-ee:<version>-ee.0
   

   The format for publishing ports is hostPort:containerPort. Read more in the Docker documentation about exposing incoming ports.

2. Enter the running container:

   sudo docker exec -it gitlab /bin/bash
   

3. Open /etc/gitlab/gitlab.rb with your editor and set external_url:

   # For HTTP
   external_url "http://gitlab.example.com:8929"
   
   or
   
   # For HTTPS (notice the https)
   external_url "https://gitlab.example.com:8929"
   

   The port specified in this URL must match the port published to the host by Docker. Additionally, if the NGINX listen port is not explicitly set in nginx['listen_port'], it will be pulled from the external_url. For more information see the NGINX documentation.

4. Set the SSH port:

   gitlab_rails['gitlab_shell_ssh_port'] = 2424
   

5. Finally, reconfigure GitLab:

   gitlab-ctl reconfigure
   

Following the above example, you will be able to reach GitLab from your web browser under <hostIP>:8929 and push using SSH under the port 2424.

A docker-compose.yml example that uses different ports can be found in the Docker compose section.

Configure multiple database connections

In GitLab 16.0, GitLab defaults to using two database connections that point to the same PostgreSQL database.

If, for any reason, you wish to switch back to single database connection:

1. Edit /etc/gitlab/gitlab.rb inside the container:

   sudo docker exec -it gitlab editor /etc/gitlab/gitlab.rb
   

2. Add the following line:

   gitlab_rails['databases']['ci']['enable'] = false
   

3. Restart the container:

sudo docker restart gitlab

Recommended next steps

After completing your installation, consider taking the recommended next steps, including authentication options and sign-up restrictions.