Excellent reading this; My Pi4/8GB cluster uses a 1000bT PoE hub for a backplane, and / is an nfsroot from a node running a Sandisk UASP USB3 SSD. Like the author, I'm blown away by the fun to be had with Docker and Kubernetes on this cluster. Unlike the author, I'm having a great experience with it as a Mac-replacing daily driver (thanks mostly to never running chromium on the same node that runs gnome-session, to spread things out a bit). Love to read about everyone's Pi cluster adventures.