<tl;dr>

mix release copies /rel/overlays/bin files
mix release foo_app doesn’t copy /rel/overlays/bin files

</tl;dr>

According to the docs, the files inside /rel/overlays/bin are copied as explained below:

The files in the rel/overlays directory are copied into every release environment.

However the files are not being copied in my setup using Umbrella. For example, the migrate script should be present in order to execute the migrations - I expected the file to be available in /app/bin/, however it doesn’t exist.

I have an Umbrella with the following structure:

- foo_app
    - rel
      - overlays/bin
         - migrate
         - server
- bar_app
    - rel
      - overlays/bin
         - migrate
         - server

I deploy foo_app running:

RUN MIX_ENV=prod mix release foo_app_release

The Docker container will only contain the shell script foo_app_release under /app/bin/. The files from rel/overlays/bin are missing in the release.

Any help is appreciated!