Local gitlab, registry, and mail server in Docker

This is a training project. Essentially, a tutor (or debugger) is needed for one task, not only to set it up but also to explain where the mistakes were.  But at least a clean installation, without explanations of my mistakes.

GitLab needs to be installed in Docker for local use. Two installation options are of interest: one on QNAP QTS and one on Ubuntu. The GitLab version is based on the sameersbn build. That is, each service in a separate container, including the runner. Plus, a registry. 

On Ubuntu, containers with macvlan are needed, on QNAP one option with the qnet driver, and if it doesn't work with qnet, then at least with a bridge. And I will try to set it up under supervision with the qnet driver. Or even by myself, the main thing is to get it running on QNAP somehow. Previously, all containers on QNAP with the qnet driver were installed without issues, but these do not want to. But maybe the problem lies elsewhere. Internet access for GitLab and the registry is not planned for now, but work with certificates is needed, of course, self-signed ones. Routing through Traefik.

The build itself is freely available on GitHub, so you can take a look in advance. It differs slightly from the one in the original assignment. But its improvements have only been welcomed. The build was liked for the "built-in" registry and auto-registration of the runner. Here: https://github.com/vasyakrg/gitlab-in-docker

And the mail server is also in Docker. A combination of dovecot+postfix+roundcube+postgres is needed. Also, each in a separate container. And also without internet access. Similarly on macvlan and qnet, that is, on Ubuntu and QNAP. The version of Dovecot should be no lower than 2.3.13. Better 2.4. It is preferable to create your own Dockerfile for the Dovecot image and include various testing tools, as the official image is extremely minimalist. For Roundcube, the following plugins are needed: 'archive', 'zipdownload', 'password', 'debug_logger', 'help', 'enigma', 'acl', http_authentication, managesieve, markasjunk, reconnect, show_additional_headers, additional_message_headers, example_addressbook (+vcard_attachments).

To emulate internet work, there is a local DNS.

I can't even imagine how much this might cost, so write to me, we will discuss.