The way we do it at my job is create a release (via exrm), we have a special config build on the build server that connects to the prod database, backs it up, migrates it up, then copies the release over and applies it (ordering is a bit different), and we only have one server for web hosting, if it goes down we have bigger issues here anyway so we would not care (even then we would not care that much except during certain times of the year).

Only rolled back once, it was manually done.

I haven’t deployed any Elixir apps myself yet but there are a couple of stickies in this section that might be of help:

And this is a popular thread about where to deploy:

We use distillery to create a basic release, from that we build an RPM and push it to a repo. For everything else we use ansible to manage - that includes configs, migrations etc. The group_vars / host_vars functionality of ansible is perfect for deployment to multiple servers and environments.

Rollbacks are also handled with ansible, by specifying a version number as a variable.