To provide fault tolerance and high availability to NSX Manager nodes, assign a virtual IP address (VIP) to the NSX cluster.
NSX Manager nodes of a cluster become part of an HTTPS group to service API and UI requests. The leader node of the cluster assumes ownership of the set VIP of the cluster to service any API and UI request. Any API and UI request coming in from clients is directed to the leader node.
When assigning Virtual IP, all the NSX Manager VMs in the cluster must be configured in the same subnet. But if external load balancer is used to configure cluster VIP, then NSX Managers and VIP can belong to a different subnet.
If the leader node that owns VIP becomes unavailable, NSX elects a new leader. The new leader owns the VIP. It sends out a gratuitous ARP packet advertising the new VIP to MAC address mapping. After a new leader node is elected, new API and UI requests are sent to the new leader node.
Failover of VIP to a new leader node of the cluster might take a few minutes to become functional. If the VIP fails over to a new leader node because the previous leader node became unavailable, reauthenticate the NSX Manager credentials so that API requests are directed to the new leader node.