Yes admission control policy is dependent on Vcenter Server although it is part of HA and we all know HA works independently of Vcenter Server. Admission control policies don’t work when at the time of failure of an ESXi host, Vcenter server is not AVAILABLE. This doesn’t mean VM that were RUNNING on failed host will not be restarted, but whatever policy you have chosen that policy will not work.

For E.g.: You have chosen “Specify failover host” policy and dedicated one ESXi host for handling the failover. Now in normal scenario, if a host failure has occurred then HA will failover the failed VM’s on only this dedicated host and not on any other hosts in cluster. But if Vcenter is not available and this happens then HA MIGHT restarts your VM’s on other hosts also if there are not sufficient resources available on your SPECIFIED failover host.

Yes admission control policy is dependent on Vcenter Server although it is part of HA and we all know HA works independently of Vcenter Server. Admission control policies don’t work when at the time of failure of an ESXi host, Vcenter server is not available. This doesn’t mean VM that were running on failed host will not be restarted, but whatever policy you have chosen that policy will not work.

For E.g.: You have chosen “Specify failover host” policy and dedicated one ESXi host for handling the failover. Now in normal scenario, if a host failure has occurred then HA will failover the failed VM’s on only this dedicated host and not on any other hosts in cluster. But if Vcenter is not available and this happens then HA might restarts your VM’s on other hosts also if there are not sufficient resources available on your specified failover host.