There’s undocumented stuff, but here’s a wall of things you can do as far as networking is concerned: fly-replay, fly-prefer-region, regional-ips, fly-force-instance-id, 6pn-only apps, 6pn with geo-DNS, 6pn with Anycast, 6pn namespaces, anchor-scaling, instance discovery, configurable - http/tls/proxy-proto handlers, 3x health-checks, Fly-managed certs and a few other things.
Fly maintains example apps up here: Fly.io Apps · GitHub
I wouldn’t know. But really, I’d use PlanetScale, Neon.Tech, Aurora Serverless v2 or some such if it were up to me.
Fly multi-process apps are still in preview (and may or may not suit your setup, hard to tell). We, personally, avoid multi-process apps but want to use them once they get better (esp, with proper request-routing and Machine apps support).
Wrong person, but others have been running these and there are docs. More specifically, some of the framework docs are excellent (but I take you’re not using Rails or Phoenix or Laravel that seems to be the area of extreme focus for Fly) I’ve been tempted by Upstash Redis, but haven’t gotten to code it up and put it to proper use.
You’re bootstrapping, or else… 