Full disclosure: I'm a customer of RackN and have used it to provision several thousand physical machines and counting. You can get a free license for RackN's

Full disclosure: I'm a customer of RackN and have used it to provision several thousand physical machines and counting. You can get a free license for RackN's digital rebar and use their edgelab.digital [1] project to pxe boot and build a four node raspberry pi k3s cluster in a few minutes. [1] https://github.com/digitalrebar/edgelab https://github.com/digitalrebar/edgelab