Intermittent issues with East-West VM connectivity

Products

• VMware NSX for vSphere

Issue/Introduction

Symptoms:

• Few VTEPs from VNI table miss from Host VTEP-table, however, Controller shows complete VTEP List.
   
• Unsynchronized changes between Controllers for affected VNI.
   
• In the /var/log/netcpa.log file of ESXi host, you see entries similar to:
  
  Vxlan: ID xxxx's controller is changed from x.y.z.a:0 to x.y.z.b
  Vxlan: send session control(1) message to the controller: VNI 5004 controller x.y.z.b
  Vxlan: receive VNI Session Control(2) message from controller: VNI xxxx controller x.y.z.b
  Vxlan: receive VNI Session Control(2) message from controller: VNI xxxx controller x.y.z.a
  Vxlan: Session mismatching for VNI xxxx ID 25 controller x.y.z.a, existing: session(23 x.y.z.b:0)
  
  Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.

Environment

VMware NSX for vSphere 6.3.x
VMware NSX for vSphere 6.2.x

Cause

This issue occurs due to a race condition which impacts controller & ESXi sync communication and causes VTEP mismatch between controller & ESXi host.

Resolution

This issue is resolved in VMware NSX for vSphere 6.3.5, available at VMware Downloads.

Note: This is a known issue affecting VMware NSX for vSphere 6.2.x.

To work around this issue if you do not want to upgrade, perform a force sync of VXLAN and Routing services.

Additional Information

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