The Cluster.NodeRole enumerated type defines the role node can be in a VCHA Cluster.
ACTIVE : Node is having a role of Active. In this role, node runs a vCenter Server that serves client requests.
PASSIVE : Node is having a role of Passive. In this role node, runs as a standby for the Active vCenter Server and receives state updates. This node takes over the role of Active vCenter Server upon failover.
WITNESS : Node is having a role of Witness. In this role, node acts as a quorum node for avoiding the classic split-brain problem.
Enumeration: ACTIVE, PASSIVE, WITNESS,