Network Extension HA layer 2 stretch fails and enters maintenance mode in HCX

Products

• VMware HCX
• VMware NSX
• VMware vCenter Server

Issue/Introduction

After successfully deploying HCX environment and configuring Network Extension High Availability (NE HA), attempts to open layer 2 stretches fail and the NE HA status displays maintenance mode instead of operational state.

Symptoms include:

• Network Extension HA configuration completes successfully and shows green status
• Layer 2 stretch requests through NE HA group fail with errors
• NE HA status changes to maintenance mode
• HCX service mesh appears operational but network extension operations do not function

Steps to validate:

• Check HCX Manager logs for connectivity errors between vCenter and NSX Manager
• Verify Network Extension appliance status in HCX Manager
• Review NSX Manager integration status with vCenter Server

Environment

VMware HCX
VMware vCenter Server
VMware NSX Manager

Cause

The issue occurs when registration between vCenter Server and NSX Manager is broken or disconnected. HCX Network Extension operations require seamless integration between compute management (vCenter) and network virtualization (NSX) components to coordinate layer 2 stretch functionality.

Resolution

Verify and restore vCenter and NSX Manager registration:

1. Check current registration status:
   • Access the NSX Manager interface
   • Navigate to System > Fabric > Compute Managers
   • Confirm vCenter Server registration status and connectivity state
2. Verify network connectivity:
   • Ensure network connectivity between NSX Manager and vCenter Server
   • Test DNS resolution between the systems
   • Verify required ports are open between NSX Manager and vCenter Server
3. Re-establish registration if broken:
   • In NSX Manager, remove the existing vCenter registration if present
   • Add vCenter Server as a compute manager with proper credentials
   • Validate authentication credentials and certificates
   • Wait for the registration process to complete successfully
4. Test integration:
   • Confirm vCenter Server shows as "UP" status in NSX Manager compute managers
   • Verify NSX networking components are visible in vCenter inventory
   • Test basic NSX operations through the vCenter interface
5. Retry HCX Network Extension operations:
   • Wait for NE HA status to return to an operational (green) state
   • Attempt layer 2 stretch configuration again
   • Monitor HCX Manager logs for successful network extension operations

Additional Information

If the error persists after following these steps, contact Broadcom Support for further assistance.

When opening a support request, provide:

• HCX Manager version and build information
• HCX log bundles from both source and destination sites
• vCenter Server and NSX Manager version details
• Screenshots of error messages from HCX Manager interface
• Network Extension appliance logs showing the failure