You can use the vCenter HA functionality to support vCenter 6.5 HA.

This component supports two new resources:
  • Passive Node
  • Witness Node

All the services are discovered in active nodes and are monitored by witness nodes. When ever the node fails, the passive nodes become active and starts discovering services. In such cases, the idle active node becomes passive.

Note: Only IP address of the active node should be configured at the vCenter adapter.