My current setup has my DHCP + DNS on my Unifi USG. However, as I have all my apps hosted on a different server (unifi, plex, home assistant, NAS, etc.) I’ve ran into issues trying to get things set up.
Basically, Unifi needs to know where the unifi server is, but it’s assigning the IP address to it.
Should I put DHCP+DNS onto it’s own system? Should I put it on my current server? And any non-Pi recommendations for systems? (I’ve had the PI filesystem clobber itself too many times)
Unifi is specific about expecting the controller address to not change. You have several options: There’s the “override controller address” setting, which you can use to point the devices at a dns name, instead of an ip address. The dns can then track your controller. It doesn’t exactly solve your issue, though, as USG doesn’t assign dns names to dynamic allocations.
Another option is to give the controller a static IP allocation. This way, in case you reboot everything, USG will come up with the latest good config, then will (eventually) allocate the IP for controller, and adopt itself.
Finally, the most bulletproof option is to just have a static IP address on the controller. It’s a special case, so it’s reasonable to do so. Just like you can only send NetFlow to a specific address and have to keep your collector in one place, basically.
I’d advise against moving dhcp and dns off unifi unless you have a better reason to do so, because then you lose a good chunk of what unifi provides in terms of the network management. USG is surprisingly robust in that regard (unlike UDMs), and can even run a nextdns forwarding resolver locally.