After you create a cluster, enable Host Monitoring so that VMware HA can monitor heartbeats sent by the VMware HA agent on each host in the cluster.

If Enable Host Monitoring is selected, each ESX/ESXi host in the cluster is checked to ensure it is running. If a host failure occurs, virtual machines are restarted on another host. Host Monitoring is also required for the VMware Fault Tolerance recovery process to work properly.


If you need to perform network maintenance that might trigger host isolation responses, VMware recommends that you first suspend VMware HA by disabling Host Monitoring. After the maintenance is complete, reenable Host Monitoring.