I've found k3s (https://k3s.io/) to be extremely easy to use for setting up and running kubernetes on a group of Raspberry Pis. Specifically, I followed this guide to get my clusters up and running quickly and it's worked out pretty well: https://blog.alexellis.io/test-drive-k3s-on-raspberry-pi/
Its easy, but it uses 50% CPU idle and it would probably use more if it weren’t blocked on SD card writes (it uses 100% SD card bandwidth). I tested this multiple times on a RPI 3B this last week with different individual Pis and different SD cards. There are also many bug reports to the same general sentiment.
I would agree here - k3s is much better suited for RPi than kubeadm, this looks like a rehash of my original tutorial from several years ago -> https://github.com/teamserverless/k8s-on-raspbian/
Today, I point folks here to get everything up and running with minimal overheads -> https://alexellisuk.medium.com/walk-through-install-kubernet...