I found this lot of seven Thinkcentre m710e SFF with Core i5 7th gen on ebay… a first step to start building my own on-prem k8s cluster :) : r/thinkpad
SZWXZY USED For Lenovo ThinkCentre M710E IB250CX Desktop Motherboard 01LM389 100% Tested Fast Ship - AliExpress
ThinkCentre M710e SFF | Compact Business Desktop | Lenovo UAE
Lenovo 180W Power Supply for M710E | Laptech The IT Store.