While there is a application supervision tree, it likely works differently than you expect. The pid returned from Application.start/2 callback is never restarted. When it crashes the application is considered failed and stopped. Restarts essentially only happen to children of supervisors you control – there’s no implicit supervisor restarting things at the application level.
So you could probably do a setup like this:
┌───────────┐
│ RootSup │ Allow no restarts
└───────────┘
│
┌───────┴──────┐
│ │
▼ ▼
┌ ─ ─ ─ ─ ─ ┐ ┌───────────┐
ImpProc │ ApplSup │ Default restart limits
└ ─ ─ ─ ─ ─ ┘ └───────────┘
│
┌─────┴────────┐
│ │
▼ ▼
┌ ─ ─ ─ ─ ─ ┌ ─ ─ ─ ─ ─
Rest │ Rest │
└ ─ ─ ─ ─ ─ └ ─ ─ ─ ─ ─
There’s also a :significant setting for OTP, which I’m not sure if you can use it yet with elixir:
