VMware Admission Control

vCenter server use admission control to ensure that sufficient resource are available in a cluster to provide failover protection and to ensure that virtual machine resource reservations are respected.

There are three type of admission control:

• Host, ensure that a host has sufficient resources to satisfy the reservations of all virtual machines running on it.
• Resource pool, ensures that a resource pool has sufficient resources to satisfy the reservations, shares, and limits of all virtual machines associated with it.
• VMware HA, ensures that sufficient resources in the cluster are reserved for virtual machines recovery in the event of failure.

Only VMwar HA could be disabled, however without it, there is no assurance that VM will be failed over after a host failure. Here is the use case for disabling VMware HA:

• DPM test
• VUM like automatic process
• maintenance process