What is a prerequisite for configuring admission control on a cluster?

To configure admission control on a cluster, it is essential to have vSphere High Availability (HA) enabled. Admission control is a feature designed to ensure that sufficient resources are always available in a cluster to restart virtual machines after a failure or host failure incident.

By activating HA, the cluster can maintain cluster-wide availability and is necessary for managing how resources should be allotted and preserved. Admission control calculates how many hosts can fail while still preserving the capacity needed to restart VMs. High Availability's primary role is related to the failover of VMs, making it a prerequisite for admission control to function effectively.

Having other features such as Distributed Resource Scheduler (DRS), Fault Tolerance, or Enhanced vMotion Compatibility (EVC) may enhance the overall resource management and VM migration capabilities but they do not directly support the admission control feature necessary for ensuring that resources are available following a host failure. Therefore, enabling HA is crucial for configuring admission control in a cluster.