Alarms for "management_channel_to_transport_node_down" and "management_channel_to_transport_node_down_long" for transport node UUID which is no longer in used

Products

• VMware NSX

Issue/Introduction

• Alarms for "management_channel_to_transport_node_down" and "management_channel_to_transport_node_down_long" is seen for transport node UUID which is no longer in used
• Below logs in seen on /var/log/syslog on NSX Manager

2026-02-02T15:02:22.428Z <nsx_manager> NSX 76200 MONITORING [nsx@6876 alarmId="####2116-####-####-####-e426477####" alarmState="OPEN" comp="nsx-manager" entId="####339d-####-####-####-07122b28####" eventFeatureName="communication" eventSev="MEDIUM" eventState="On" eventType="management_channel_to_transport_node_down" level="WARNING" nodeId="<TN_UUID>" subcomp="monitoring"] Management channel on <nsx_manager> to Transport Node #.#.#.# (#.#.#.#) is down for 5 minutes.
2026-02-02T15:02:22.465Z <nsx_manager> NSX 76200 MONITORING [nsx@6876 alarmId="####0093-####-####-####-9fdca5bc####" alarmState="OPEN" comp="nsx-manager" entId="####339d-####-####-####-07122b28####" errorCode="MP701099" eventFeatureName="communication" eventSev="CRITICAL" eventState="On" eventType="management_channel_to_transport_node_down_long" level="FATAL" nodeId="<TN_UUID>" subcomp="monitoring"] Management channel on <nsx_manager> to Transport Node #.#.#.# (#.#.#.#) is down for 15 minutes.

• The old Transport Node was not removed properly when decommissioned earlier.
• Below similar logs could be seen on /var/log/messaging-manager/messaging-manager.log

     {
        "details": [
          {
            "failure_code": 8804,
            "failure_message": " Host configuration: Failed to send the HostConfig message. [TN=TransportNode/<TN_UUID>]. Reason: Failed to send HostConfig RPC to MPA node:<TN_UUID>. Error: Unable to reach client <TN_UUID>, application SwitchingVertical.",
            "state": "orphaned",
            "sub_system_id": "<TN_UUID>",
            "sub_system_type": "Host"
          }
        ],
        "failure_code": 8804,
        "failure_message": "Host configuration failed. Number of retries : 5744. Next retry attempt will be between 2026-Feb-03 19.35.17 PM and 2026-Feb-03 19.38.17 PM (UTC).",
        "maintenance_mode_state": "DISABLED",
        "state": "orphaned",
        "transport_node_id": "<TN_UUID>"
      } 

Environment

VMware NSX

Cause

Host connectivity for stale Host causing Transport Node to fail/retry continuously leading to management channel alarm. 

 

 

Resolution

To resolve this:

1. Follow Option 2 from KB: https://knowledge.broadcom.com/external/article?articleNumber=319975 

2. Then Force delete once the TN is in standalone  host 

 

Note:

The correct procedure to remove NSX from a single host:

• Uninstall NSX Data Center from a Managed Host in a vSphere Cluster

Additional Information

https://knowledge.broadcom.com/external/article?articleNumber=319975