How to choose: answering the main questions
What does a private cloud consist of?
Minimum: two virtualization nodes and shared storage (or Ceph on the same nodes), plus backup. Proxmox covers 90% of scenarios for free: clustering, live migration, snapshots, and software-defined storage.
How many nodes should I start with?
Three is the optimum: cluster quorum, failure of any node without downtime, and true Ceph. A budget-friendly start is two nodes with replication. One server is still virtualization, but no longer a cloud.
What hardware is required for nodes?
Balanced dual-processor platforms: 2× Xeon Gold, 256–512 GB memory, NVMe for cache and SSD/HDD for data, 2× 10/25GbE. Identical nodes simplify migration and maintenance.