NSX v2T Migrating a DLR with no VMs connected to a downstream logical switch fails

Products

• VMware NSX

Issue/Introduction

• When no VM is connected to a logical switch attached to a Distributed Router in NSX-v, you experience these symptoms:
• Migration of NSX-v Edge to NSX-T within the V2T Migration tool fails.
• Error similar to the below is observed:
  
  Config migration failed [Reason: [NSCutover] Can not proceed with migration: Transit logical switch not found on LR].

Environment

VMware NSX-T Data Center 3.x

VMware NSX 4.x

Cause

This issue occurs due to the DLR interface missing a VM attachment on a downlink in the NSX-T Distributed Logical Router. This causes the Logical switch to not be created although configured. When the DLR has no VMs on the downlink, the transit switch also does not actually create.

Resolution

This is a condition that may occur in a VMware NSX environment.

To resolve this issue, there should be at least one workload VM on DLR downlink interface on NSX-v DLR prior to migration.