SDDC precheck fails with NSX audit not connected transport nodes validator failed error

Products

• VMware NSX

Issue/Introduction

Precheck failures block the VMware Cloud Foundation (VCF) SDDC upgrade process when the NSX host status displays as Unknown in the NSX UI. SDDC prechecks fail with the specific error message: NSX audit not connected transport nodes validator failed. This article provides steps to resolve this state caused by opsagent communication failures

• The logs record repeated network errors:

  StreamConnection[... Closed to tcp://127.0.0.1:9100 sid:-1] Closed (reason: network error, error: 32-Broken pipe)

Environment

• VMware Cloud Foundation 5.2.3.0
• VMware NSX 4.2.3.3
• VMware vSphere ESXi 8.0 U3g

Cause

The NSX opsagent service on the ESXi host experiences an internal communication failure due to a broken pipe connection on the local socket (port 9100). The nsx-syslog.log from the affected ESXi host typically shows the following:

StreamConnection[... Closed to tcp://127.0.0.1:9100 sid:-1] Closed (reason: network error, error: 32-Broken pipe)

Because this agent reports and updates the host's health status to the NSX Manager, the communication breakdown results in an Unknown host status, triggering the transport node validator failure.

Resolution

1. Place the affected ESXi host into Maintenance Mode.
2. Reboot the ESXi host. This ensures all NSX services stop and start safely in the correct order, cleanly re-initializing the local network stack to resolve the broken pipe issue on port 9100.
3. Once the host comes back online, verify that the host status reflects as Up in the NSX UI.
4. Re-run the SDDC prechecks to continue the upgrade.

To gather a support bundle from the ESXi host, see Collecting diagnostic information for VMware ESXi using vSphere Client

If you require further assistance, see Contact Broadcom support  to speak with a Support Engineer.