The NSX Manager cluster health is reported as Degraded within the UI

Products

• VMware NSX

Issue/Introduction

• NSX manager cluster is in 'DEGRADED' state and manager node is marked 'Unavailable'.

         

• NSX managers are in different subnets. Inter-node connectivity test reveals a communication failure between specific manager nodes (e.g., Manager 1 and Manager 2), while other nodes maintain partial reachability. NSX managers are unable to ping or resolve ARP of the manager in 'Unavailable' state.
  
  
• Use the following command to ping from NSX manager CLI - 
  nsx-mngr-01> ping <ip-address>
• Use the following command to check default gateway -
  nsx-mngr-01> get routes

Environment

VMware NSX

Cause

This can happen because of inter-node connectivity failure within the physical underlay network or firewall infrastructure. NSX Manager clusters utilize the Corfu distributed database and cluster management services that require a majority quorum and "full-mesh" communication between all nodes to maintain a Stable state.
In environments where managers reside on different subnets, routing disruptions or blocked ports prevent heartbeats and database synchronization.

Resolution

Fix connectivity issue between manager nodes and ensure that the required ports are open in the network.
Please refer to following document for list of ports and protocols.
VMware Ports and Protocols

Additional Information

Refer to Cluster Requirements for an Individual Site for requirements and recommendations.