A vCenter HA cluster consists of three vCenter Server Appliance instances. The first instance, initially used as the Active node, is cloned twice to a Passive node and to a Witness node. Together, the three nodes provide an active-passive failover solution.

Deploying each of the nodes on a different ESXi instance protects against hardware failure. Adding the three ESXi hosts to a DRS cluster can further protect your environment.

When vCenter HA configuration is complete, only the Active node has an active management interface (public IP). The three nodes communicate over a private network called vCenter HA network that is set up as part of configuration. The Active node and the Passive node are continuously replicating data.

Figure 1. vCenter Three-Node Cluster
The three-node cluster consists of an active, passive, and witness node. A private network is used for communication between the three nodes.

All three nodes are necessary for the functioning of this feature. Compare the node responsibilities.

Table 1. vCenter HA Nodes




  • Runs the active vCenter Server Appliance instance

  • Uses a public IP address for the management interface

  • Uses the vCenter HA network for replication of data to the Passive node.

  • Uses the vCenter HA network to communicate with the Witness node.


  • Is initially a clone of the Active node

  • Constantly receives updates from and synchronizes state with the Active node over the vCenter HA network

  • Automatically takes over the role of the Active node if a failure occurs


  • Is a lightweight clone of the Active node

  • Provides a quorum to protect against a split-brain situations