We use Hetzner too. With their CLI tool, you can deploy a new VM, install OTP, rsync your program, release, download, shutdown and you’d incur in 15 minutes of usage total… so just a few € cents.

I build releases for ARM systems on an x86 build server.

I take the files for the ARM system’s ERTS, place them on the build server and then reference them in the release I am building.

Here is a snippet from the mix.exs, “releases” section:

  releases: [                                                                                                               
    sra_rps: [
      overwrite: true,
      include_executables_for: [:unix],

      # Keep the docs
      strip_beams: [keep: ["Docs", "Dbgi"]],

      # Path to the ERTS copied from ~/.asdf/installs/erlang/24.2.1
      include_erts: "/usr/local/share/erlang_rps/erts-12.2.1",
      ...

The only provisio is that building any NIFs or port programs becomes much more complicated. The only port programs I have are very stable, never needing changes, so I include compiled versions as binaries in priv.

In my case, I’m using:

1. an x86_64 linux emulator
2. a docker service running on above emulator

When building x86_64 docker image, I use above docker service.

On my MBP 2015, the build can be done in 4 min. But in the emulator on MBP 2021, the building process can slow 4 times, I think. (I didn’t measure it precisely. All I know is that my tea will be cold after the build. )

That’s exactly the reason why I push all my builds to CI from day 1. Usually the free plans are enough for my private stuff and for non private stuff a few bucks a month should be doable. No need to worry about where and how I do my edits, could even be the built in editor of the service hosting the repo for what it’s worth. I totally see that being a bit more work upfront, but it’s documented in code and rather flexible.

Oh, and here’s the configuration I ended up with (permalinked to the current version, so maybe check if it has changed if you come from the future): .gitlab-ci.yml · e037b3c8245f2db487a13539062de726749b6156 · CodeStats / code-stats · GitLab

Let me know if you think I could do something better!