HCX - Modifying NSX-T segment names may cause issues with MON features

Products

• VMware HCX

Issue/Introduction

• The network was extended by HCX in a version prior to NSX-T 3.2.
• The L2E_<name> segment was renamed on the NSX target after being extended by HCX.
• The MON feature was enabled after the segment was modified on the NSX target.
• The MON task completed without errors, however, connectivity will fail because adding the static route for <IP>/32 fails.
• The following errors are observed in /common/logs/admin/app.log:

2024-05-14 21:51:09.689 UTC [NetworkStretchService_SvcThread-217606, j: b9e04809, s: 89bc3516, , TxId: 0bf95a0a-9e92-4d16-b39e-69698f0d39a5] WARN  c.v.v.h.n.ConfigureHostRoutesOnEdgeJob- Failed to add static route {"network":"###.###.###.###\/32","display_name":"HCX Policy based MON for Subnet ###.###.###.###\/22","resource_type":"StaticRoute","next_hops":[{"scope":["\/infra\/segments\/hcx-ne-<id>"]}]}, error {"status":"failure","statusCode":400,"details":"","result":

• Even though the segment is connected to the T1 router and the T1 router is connected to the T0 gateway, the following error was reported:
   

{"httpStatus":"BAD_REQUEST","error_code":528039,"module_name":"Policy","error_message":"Segment \/infra\/segments\/hcx-ne-<id> is not connected to Tier0\/1 Gateway."}}

Environment

NSX 3.1.x
HCX

Cause

When changes are made via the NSX-T manager to an extended segment on older NSX-T versions, the communication is broken due to changed reference points. The issue occurs because the segment's name was changed, causing the HCX manager's API call to fail with a specific error code (400), indicating a bad request.

Resolution

This issue has been resolved in the later NSX versions of NSX 3.2.x. 

Workaround 

For any renamed segments that are affected, the following steps must be followed to recreate them, and changes must only be introduced to them once they are unstretched.

• Move the VM to a temporary segment.
• Unextend the extended segment.
• Delete the segment from the Destination NSX. 
• Extend the segment. 
• Move the VMs back and enable the MON.

Additional Information

Impact/Risks:

• Modifications to the renamed segment, such as enabling MON, may cause connectivity issues.
• The existing Network Extension should continue to operate normally.