VMware #NSX 6.3 Controller – Failure / Data loss behaviour

It’s been a month since NSX 6.3 has been released. It just came to my attention that an unknown behaviour of the NSX-Controller has been changed with that release.

We have 3 NSX-Controller while 2 of them should at least be available to remain complete functional. As we all hopefully now the NSX-Controller manages tables (VTEP, MAC, ARP) for Layer-2 VXLAN Operations (if we have selected hybrid or unicast as a replication mode).

NSX-Controller Failure

The following tables tries to explain the impact of controller failures in case we are in Unicast or Hybrid-Mode in case of Layer-2 switching functionality:

NSX Controller Available Cluster-Status NSX-Controller Operations Mode Impact
3 healthy read/write No Impact
2 degraded read/write No Impact
1 degraded read only New VMs or vMotioned VMs will have networking issues
0 headless(-chicken) New VMs or vMotioned VMs will have networking issues

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