Elixir and Erlang deployments were tricky a few years ago, but I feel like now with distillery [0] it a lot better. I use it in docker multistage builds [1] and have been really happy with that.

[0] https://github.com/bitwalker/distillery

[1] example dockerfile: https://gist.github.com/bsedat/16cb74ebc8ab0ed61ac598a129b0a...