NSX Transport Nodes appear 'Degraded' due to a disconnected host in the same cluster

Products

• VMware NSX

Issue/Introduction

In a NSX environment, most ESXi transport nodes in the same cluster exhibit the following symptoms:

• Node Status: The overall node health is reported as Degraded in the NSX Manager UI (System > Fabric > Hosts). One host node in this cluster is Host Disconnected status.
• Tunnel Status: Multiple Geneve (VTEP) tunnels are reported as Down on the affected hosts.

Environment

VMware NSX

Cause

This issue occurs because one specific host in the cluster is in an abnormal state (e.g., Not Responding in vCenter or Disconnected in NSX).

In an NSX transport zone, transport nodes attempt to form a mesh of BFD tunnels with all other active nodes. If a single host (e.g., esx01) becomes disconnected or unresponsive, all other healthy hosts in the same cluster will lose their tunnel connections to that specific host. Consequently, those healthy hosts will report a Degraded status because their required tunnel mesh is incomplete, even though their physical networking is functional.

Resolution

To resolve the degraded status, identify and fix the "source" host that is disconnected.

Step 1: Identify the Abnormal Host

1. Log in to the NSX Manager UI.
2. Navigate to System > Fabric > Hosts.
3. Review the list of hosts in the affected cluster to find any node with a status of Disconnected, Not Ready, or Orphaned.
4. Cross-check the host status in vCenter Server to see if the host is responding.

Step 2: Restore Host Connectivity

1. Troubleshoot the identified abnormal host (e.g., resolve hardware/power issues).
2. Ensure the host returns to a good state in both vCenter and NSX Manager.

Step 3: Verify and Sync Remaining Nodes

1. Once the source host is back online, the tunnels on the other hosts should automatically begin to recover.
2. For any hosts that remain in a Degraded state:
   • Select the host in the NSX Manager UI.
   • Click Actions > Sync Transport Node.
3. Verify that all BFD tunnels are now Up and the overall node status has returned to Healthy.

Additional Information

NSX Host Node Tunnel Status is 'Degraded': https://knowledge.broadcom.com/external/article/409965

Troubleshooting NSX TEP/BFD Tunnels between ESXi hosts and Edges: https://knowledge.broadcom.com/external/article/379112