OK, that’s a really weird way of installing Erlang and Elixir but there are likely not many officially blessed ways under CentOS – not an expert on it.
Still, I am curious why didn’t you use Hex.PM’s official Docker images?
Have you also tried put CMD /bin/topo_master start at the end of the Dockerfile so you don’t have to get inside it to start the app?
These might not be strongly related to your problem but I’d go through such a laundry list to make sure it’s not something in earlier stages of the deployment decisions.
