As tests on Rock PI-X were successful, I ordered five other units. The Rock PIs come from China and even if shipping usually takes more than two weeks, it is more than time to prepare provisioning tools.

Before buying all the nodes of the cluster, it is worth testing a unit. The short list of candidates was quickly drawn:

Chinese manufacturers offer a large choice of low-cost, fanless, servers. I chose one with more than enough power and four Ethernet plugs. Only two RJ45 connectors were needed but additional ones allow me to split the cluster in two sub-nodes and test consequences of inter-networks communication. For example, a kubernete-to-kubernetes cluster connection might be tested.

Directly powering all components would require to plug 6 (cluster nodes) + 1 (cluster server) + 1 (switch) = 8 wires! Added to the cable mess it would imply inefficient powering with at least 6 low-cost power adapters.

The structure of the mini cluster should stay simple to ease build and setup. The following hardware architecture should be just enough: