I deploy the Erlang system I use at work using Docker and it's working very well for me. Like you say, it's not a zero-downtime relup but rather just replacing one app container by an updated one. It was a little bit tricky to get the image built properly (the right combination of dependencies, ERTS inclusion, etc) and things like remote_console are slightly more cumbersome than they would be otherwise (it becomes a docker exec command) but overall I feel like the advantages (mainly very smooth deployment and declarative configuration) outweigh the disadvantages.