I am documenting my experience creating a render server for the kdenlive project using Docker. Although some of the findings are not optimal, they are the solutions I found to the problems. I believe that this information will be useful to other people with similar issues.
There was a server available with four GeForce GTX Titan Black GPUs, running Debian 9 Stretch. However, the system was outdated, and I could not upgrade it since other users were running projects on that server.
My first attempt was to install ffmpeg and melt, but I couldn't because the apt sources were outdated. I then tried to enable backport repositories, but I was unable to install the packages.