Error 502 and very slow web interface with new Gitlab CE installation


I used this Dockerfile to install Gitlab CE v7.11.2 on a virtual Linux server with a single core, 2GB RAM and 3 GB Swap (SSD). The server is used only to evaluate GitLab, and no other processes are running, and the resources mentioned above are statically available and guaranteed.

The installation went well, and the whole three containers ending up eating about 400MB of RAM, with Sidekiq being the largest consumer (about 300MB).

Accessing GitLab works as well, but the page loads take very long (several seconds after each click, the red bar moves very slowly). I did not expect a fast system with using only one core, but this was nearly unusable. The real problem is, that I cannot create a new project, as the web runs into a 502 - GitLab is not responding - message.

Neither the CPU load, nor the memory consumption is very high. Is there anything I can try to get GitLab to run at least a little bit faster, so I can create projects without running into a timeout?

Thanks in advance!