1. Add following to your /etc/gitlab/gitlab.rb
<file - /etc/gitlab/gitlab.rb>
external_url 'https://git.yourdomain.tld'
nginx['listen_address'] = 'localhost'
nginx['listen_port'] = 8888
nginx['listen_https'] = false
</file>
2. Reconfigure gitlab-ce
<code bash>gitlab-ctl reconfigure</code>

3. Create a subdomain or domain alias

{{:start:howto:gitlabimscpconfig.png?800|}}

4. Enable needed headers module
<code bash>a2enmod headers</code>

5. Configure Letsencrypt entry (when available)

**or** 

6. Create certificate and copy to /etc/gitlab/ssl/git.yourdomain.tld.pem (decrypted private, public, intermediate)
7. Reload apache2 service
<code bash>apache2 reload</code>