HCX - "Unable to find Layer2 id for segment“ error during Network Extension of an NSX-T Overlay Segment

Products

• VMware HCX
• VMware NSX-T Data Center

Issue/Introduction

• When an HCX Connector or Cloud manager initiates a Network Extension for an NSX-T overlay segment the following error may be returned. As a result the Network Extension fails
  
  Failed Extension. Check entries below for errors. Please allow network stretch for overlapping vlan if you still want to extend this network.
  
  
• HCX Manager UI - Administration - Activity Logs reports
  
  
  • Error: Unable to find Layer2 Id for segment /infra/segments/<segment-name>
  
  
  
  
  
• The following error is observed in /common/logs/admin/app.log:
  
  2024-10-24 04:27:32.631 UTC [NetworkStretchService_SvcThread-162, j: eadba2a4, s: 50291c71, , TxId: d2690b78-704c-436f-83ae-7bde036ab751] WARN  c.v.v.h.n.i.AbstractJobInt- Exception in NetworkStretchJobs:ExtendNetworkWorkflowInt. Reason : Unable to find Layer2 Id for segment /infra/segments/<segment-name>
2024-10-24 04:27:32.631 UTC [NetworkStretchService_SvcThread-162, j: eadba2a4, s: 50291c71, , TxId: d2690b78-704c-436f-83ae-7bde036ab751] ERROR c.v.v.h.n.i.NetworkStretchJobInt- Error encountered in Network Stretch job
java.lang.RuntimeException: Unable to find Layer2 Id for segment /infra/segments/<segment-name>

Impact/Risks

The HCX Network Extension operation fails for the segment being extended

This issue may occur if the NSX-T manager is upgraded to a 3.1.x version prior to 3.1.3.5 where the issue is fixed, and the HCX manager is running version 4.3.0 or higher at the site initiating the Network Extension

Environment

VMware HCX
VMware NSX-T

Cause

During an HCX Network Extension operation, the NSX-T manager does not provide the overlay_id to the HCX Manager that is associated with the segment being extended. The VNI ID present in the NSX-T manager is reflected as overlay_ID in the "extended_attributes" of the GPRR table. This "overlay_id” was added to GPRR in NSX-T 3.1.x. However, in 3.1.x versions before 3.1.3.5, this overlay_id parameter is missing whenever an API call is made for getting details of segments.

Resolution

This issue is resolved in NSX-T 3.1.3.5 and later releases.

Note: As this is not an HCX issue. For more information on this issue with versions of NSX 3.1.3.5 or earlier please open a Broadcom case with VMware NSX as product.