Configure GitLab running in a Docker container

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This container uses the official Linux package, so you can use the unique configuration file /etc/gitlab/gitlab.rb to configure the instance.

Edit the configuration file

To access the GitLab configuration file, you can start a shell session in the context of a running container.

Start the session:

sudo docker exec -it gitlab /bin/bash

Alternatively, you can open /etc/gitlab/gitlab.rb in an editor directly:

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

In your preferred text editor, open /etc/gitlab/gitlab.rb and update the following fields:
1. Set the external_url field to a valid URL for your GitLab instance.
2. To receive emails from GitLab, configure the SMTP settings. The GitLab Docker image doesn't have an SMTP server pre-installed.
3. If desired enable HTTPS.
Save the file and restart the container to reconfigure GitLab:
```
sudo docker restart gitlab
```

GitLab reconfigures itself each time the container starts. For more configuration options in GitLab, see the configuration documentation.

Pre-configure Docker container

You can pre-configure the GitLab Docker image by adding the environment variable GITLAB_OMNIBUS_CONFIG to the 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 (;).

The following example 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 occupies specific ports inside the container.

If you want to use different host ports from the default ports 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:

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

NOTE: The format to publish ports is hostPort:containerPort. Read more in the Docker documentation about exposing incoming ports.

Enter the running container:
```
sudo docker exec -it gitlab /bin/bash
```
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'], the external_url is used instead. For more information, see the NGINX documentation.

Set the SSH port:

gitlab_rails['gitlab_shell_ssh_port'] = 2424

Finally, reconfigure GitLab:
```
gitlab-ctl reconfigure
```

Following the above example, your web browser can reach your GitLab instance at <hostIP>:8929 and push over SSH on port 2424.

You can see a docker-compose.yml example that uses different ports in the Docker compose section.

Configure multiple database connections

Starting 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:

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

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

Add the following line:

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

Restart the container:
```
sudo docker restart gitlab
```

Next steps

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