After NSX Edge VM replacement from NSX UI, Edge node shows as Unknown in T0 Gateway

Products

• VMware NSX

Issue/Introduction

• A Faulty NSX Edge VM was replaced with a new one.
• After replacing an NSX Edge VM, the replaced Edge Node's status appears as Unknown instead of Active/Standby under the corresponding Tier-0 (T0) or Tier-1 (T1) Gateway.

• The T0/T1 Gateway status shows as Down.

• When running specific commands like get logical-router / get gateways / get vteps on the affected Edge Node's CLI, there is no output.

• Running commands "get controllers" and "get managers" will result as connected.

Environment

VMware NSX 4.2.1.3

Cause

• The issue is caused by an incomplete or unsuccessful realization of the Tier-0 or Tier-1 Gateways on the newly replaced Edge Node.
• This typically happens when the NSX Manager(s) have not correctly pushed the configuration and state of the logical routers to the newly deployed Edge VM, even though basic control plane connectivity is established. This prevents the routing components from starting up and reporting their proper status, leading to the Unknown state.

Resolution

Perform a rolling reboot of the NSX Managers to force a resynchronization of the entire NSX-T control plane state, including the realization of logical routers (T0/T1 Gateways) on the Edge Nodes.

This will force a re-realization of the configuration by triggering a restart of the central control plane components.

Additional Information

Reboot an NSX Manager