Hosts that are added to a DRS cluster must meet certain requirements to use cluster features successfully.

Note: vSphere DRS is a critical feature of vSphere which is required to maintain the health of the workloads running inside vSphere Cluster. Starting with vSphere 7.0 Update 1, DRS depends on the availability of vCLS VMs. See vSphere Cluster Services (vCLS) for more information.