

If you have a server running, I wouldn’t buy more hardware. They have good example documentation for just such a configuration:
https://docs.pi-hole.net/docker/
If your server already has those ports bound (specifically the DNS port 53) you are going to have to get creative; otherwise it’ll work well!
Worst case, a cheapo pi 3 will do the job. At one point I had it running on a pi zero, so hardware requirements are pretty low.
Thanks, PoopMonster, that’s a good tip!