The structure of the mini cluster should stay simple to ease build and setup. The following hardware architecture should be just enough:
minicluster hardware architecture
A generic server provide global services to all nodes such as:
- Provisioning: Operating System deployment and basic configuration.
- Naming and addressing: with local DNS and DHCP servers.
- Gateway: the server is the single access for the nodes to Internet.
- Command and control: configurations and installations on the whole cluster are performed from the server.
The question now is which technical solution for cluster nodes and at which price? As it is a personal cluster, I try to keep the price tag low and ARM-base Small Board Computers (SBC) like Rock64 or Raspberry PI 4 are cheap. On the other hand, using X86_64 CPUs would give access to a wider range of ready-to-use software and containers.