Sometimes you don't need a container for a nice web application. Sometimes you just need to test packaging or building in an environment that isn't a virtual machine, ephemerally. Sometimes you need a quick and easy container to punt stuff into, then see what damage it causes. This is exactly what that is for.
I did some testing on Ubuntu 18.04, from 16.04, and needed to replicate the manual work I was doing with 16.04 in development, in an automated fashion for 18.04. Working with GNU screen, I learned that you can send commands, and script a bunch of things from the startup.
This is a skeleton project for working with building and running such containers. I orchestrated with ansible previously, and you can still do that here (it runs sshd, just ad python3 package to the install)
Might be useful, might not. I learned a lot more about screen and container environments that I expected to by doing this.
Do not use this in a production environment. No user is created, and the entrypoint script runs as PID 1, with whatever commands you dump in. This is useful for testing purposes only, and you want to inject an ssh-key for real security. This is provided only as a skeleton, and a learning tool.
License for files in the repo are MIT, software licenses from built container are many and varied.