There are two things to be aware of here:
- Postgres clusters are pseudo managed, we upgrade them quite frequently. You can deploy a postgres cluster manually that we won’t treat as part of the “postgres fleet”, if you’d like, and we won’t perform any automated maintenance on it.
- Apps on Fly are not like traditional VMs and will stop/start/migrate frequently as part of automated system changes. These should always be zero downtime (unless we have an actual outage), but you should expect individual app VMs to be disposable.
These are things we should document, and it’s good you opened this discussion. Hopefully the way we run these works for you and you won’t need to migrate!