I’m running a 3 pi cluster with k3s at the moment. The main benefit I’ve found is that all my pis run exactly the same software setup as a base so it’s easy to add new ones or replace/update one. I use a deployment management application to push my deployments too which means it’s super easy to redeploy everything if something goes funky.

A k8s cluster can run on a single host if that’s what you want. I’m not sure if it would be worth the virtualisation cost to run it on VMs in the middle as well. If you were only ever going to run on a single host I probably wouldn’t use k8s though, I would just run containers. 🤷‍♂️