Umbrella applications are code-design concepts - just an easy way to develop related applications together and share code etc.

What you want is to create two different releases:

Release A will run App + AppWeb
Release B will run App + AppMarketing

This will work if the App is a library application, i.e., just a bunch of functions without its own supervision tree. If however it starts its own tree, which for example is the case if it uses Ecto, you would be better placed to run it only once. You will need to add extra configuration to your apps to teach them how to find the other nodes, and deal with Heroku’s daily restarts, firewalls, internal networking and so on.

All that said, as you’ve found out, dealing with complicated releases and distributed Erlang/Elixir adds significant complexity in your Ops. Since you don’t need to change your code dramatically to do this split later on, it’s best to start by running everything on a single node.

I’ve been serving multiple apps with a custom endpoint proxying to the other endpoints. The other endpoints had server: false in their configuration. However I recently started using websockets and that’s where this setup fell short. Now I use a nginx proxy in front of the application. So still one application on heroku serving multiple applications with multiple endpoints.

https://github.com/heroku/heroku-buildpack-nginx

Hi @arjun289
I’m running an umbrella app with websockets on Heroku for over a year now, without any trouble

Here is my setup: Cowboy 2.5 proxy, used to bind a single port (on Heroku) for umbrella Phoenix applications. It supports HTTPS and websockets properly. · GitHub