VM network connectivity failure after NSX-V to NSX-T migration due to Tier-1 gateway realization failure (Ipv6NdraProfile)

Products

• VMware NSX

Issue/Introduction

• Following an NSX-V to NSX-T migration, Virtual Machines (VMs) are unable to reach the internet or external networks.
• The V2T migration was initiated from SDDC manager/VCF
• In the NSX Manager UI, the Tier-1 Gateway status is in a Failed state 
  
• Clicking the "Failed" status link reveals the following error message: Realization failure, waiting for realization of [{Ipv6NdraProfile}] <UUID>. Realization will be reattempted in next cycle (max 5 minutes)

• Searching for the UUID provided in the error message shows the profile is in an uninitialized state.
  
• Status on Transport Nodes indicates no Transport Node was found for that specific profile.
  

Environment

VMware NSX

VMware Cloud Director (VCD)

Cause

This issue occurs when an IPv6 Neighbor Discovery (ND) Router Advertisement (RA) Profile (Ipv6NdraProfile) remains in an uninitialized state after the migration process. Because the Tier-1 gateway is waiting for this profile to be successfully realized, it remains in a "Failed" state, preventing the underlying network configuration for the VMs from becoming active

Resolution

To restore network connectivity, the uninitialized ND profile must be removed so the Tier-1 gateway can reach a "Success" state.

1. Log in to the NSX Manager UI.
2. Navigate to Networking > Tier-1 Gateways.
3. Locate the Tier-1 Gateway in the Failed state.
4. Confirm the error details match the Ipv6NdraProfile realization failure.
5. Remove the Neighbor Discovery (ND) profile associated with the failing Tier-1 gateway.
   
6. Delete the Neighbor Discovery (ND) profile from the ND profiles tab.
7. Monitor the status of the Tier-1 gateway. It should automatically transition to Success within a few moments.
8. Verify that the VMs associated with this gateway can now reach the internet and other network segments.

Note: If there are any segments or security rules associated with the profile still in a failed state, please edit the object's description or comment field within VCD or NSX and save the change. This minor update acts as a trigger to restart the configuration flow and push the object into an initialized state.

To receive more detailed information or assistance, please open a Broadcom Support case. For more information, refer Creating and managing Broadcom support cases

Additional Information

For more information on recommended versions and known issues during migrations, see Recommended minimum version for NSX-V to NSX-T migration