vSphere cluster is a collection of ESXi hosts managed by vCenter server.
- To enable workload management, at least 3 ESXi hosts are required; if you are using VSAN, at least 4 ESXi hosts are required.
- vSphere cluster must be configured with high-availability (HA) enabled.
- vSphere cluster must be configured with Distributed Resource Scheduler (DRS) enabled and must be set to fully automated mode.
- The cluster must use shared storage for vSphere HA, DRS, and for storage persistent volumes.