Cluster for an appliance-type deployment

Dear all,

I’m reasonably experienced with Postgres with simple (single, „rebuild and restore“) requirements, but would need some hints on what to look for in a more complex situation - deploying Postgres as the backend for a (virtual) appliance.

This appliance can scale horizontally from a single to dozens of VMs (theoretically more, but most installations are small-ish). It is feasible to configure VMs for particular purposes (eg „you are [also] a DB node“), but basically all instances will/should be able to perform their main tasks besides (also) being a DB node. As the VMs may be installed in very different environments, network-based solutions are less feasible and we would prefer a DB-level solution. We assume that for most cases, primary/stand-by configurations would be sufficient in terms of availability / latency / throughput.

We must also assume that there is no person who would be able to touch things if an error occurs. Data consistency and (as much as possible) automated recovery from error situations („VM down“, „network lost“, …) are therefor more important than „n nines". We can assume that the VMs can talk to each other over TCP (eg using SSH tunnels, direct Postgres connection, or some other suitable protocol). Scripting „around“ the database is available to initialize instances and for similar tasks.

Would Postgres’ own log-shipping (file-based + streaming replication, possibly with remote_write) be sufficient for such a set of requirements?

What aspects would you consider important for such a scenario?

PS: In case it matters, OpenBSD is the base platform of the VMs.

Thanks for your inputs!

— Matthias