Missing Overlay Tunnels on NSX Edges towards other cluster edges and ESXi hosts

Products

• VMware NSX

Issue/Introduction

 

• The overlay tunnel mesh from specific NSX Edges to other cluster edges and ESXi hosts is not forming.

• Communication remains limited to edge-to-edge tunnels within the same cluster where a single Tunnel Endpoint (TEP) remains functional.

• Observations indicate that no overlay segments are currently connected to the Tier-1 (T1) or Tier-0 (T0) gateways hosted by the affected edge cluster.

 

Environment

VMware NSX

Cause

 

• Tunnel mesh establishment between NSX Edges and ESXi hosts operates as a demand-based mechanism for overlay tunnels.

• Design specifications require active overlay segments to be attached to the logical routers hosted on the edge cluster to trigger tunnel formation.

 

Resolution

 

• Connect at least one active overlay segment to the Tier-1 or Tier-0 gateway residing on the edge cluster.

• Verify that the segment has gateway connectivity toggeled on and attached to a transport zone reachable by the intended ESXi hosts.

Additional Information

 

• Direct edge-to-edge tunnels within the same cluster may persist for internal control plane health, but host-to-edge data plane tunnels remain down without active segments.

• Refer to the NSX-T design guide regarding demand-based tunnel formation as documented in the standard architectural prerequisites.