4 nodes for k8s is a bit problematic, because if you follow best practice, you blow three nodes for the control plane. You could run workloads on them as well (by adjusting the taints), but once you start adding things like ceph or minio, things get tight.
Has anyone played with doing a PCB with the u.2 connectors running to an on-board PCIe switch? Maybe on the order of 8 or more nodes?
I know there was plans for something larger, but it seems to have disapeared.
Christopher