You can stretch an NSX-T cluster in the management domain or in a VI workload domain across two availability zones within a region. Both availability zones must contain an equal number of hosts to ensure failover in case any of the availability zones goes down.

The default management cluster must be stretched before a workload domain cluster can be stretched. This ensures that the NSX control plane and management VMs (vCenter, NSX, SDDC Manager) remain accessible if the stretched cluster in the second availability zone goes down.
Note: You cannot stretch a cluster in the following conditions:
  • If a cluster uses static IP addresses for the NSX-T Host Overlay Network TEPs
  • If remote vSAN datastores are mounted on any cluster
You may want to stretch a cluster for the following reasons.
  • Planned maintenance

    You can perform a planned maintenance on an availability zone without any downtime and then migrate the applications after the maintenance is completed.

  • Automated recovery

    Stretching a cluster automatically initiates VM restart and recovery, and has a low recovery time for the majority of unplanned failures.

  • Disaster avoidance

    With a stretched cluster, you can prevent service outages before an impending disaster.

This release of Cloud Foundation does not support unstretching a cluster.