MAC address is not retained using the "Retain MAC" option after migrating a virtual machine using HCX within the same VC (Single vCenter Operation)

Products

• VMware HCX

Issue/Introduction

• You are migrating a virtual machine using HCX Bulk Migration within the same vCenter (Single vCenter Operation) and have selected the "Retain MAC" option.
  Note: This issue is only affecting Single vCenter Operation, where the source and target VM are on the same vCenter, but it was migrated to a different cluster (both HCX Manager (source/destination) are also registered to the same vCenter). 
• Post-migration, you observed that the MAC address for the migrated VM (target) was not retained, and the virtual machine received another MAC address.
• From vCenter logs /var/log/vmware/vpxd/vpxd.log, the following error is observed:

  <timestamps> info vpxd[07030] [Originator@6876 sub=InvtId opID=TxId: ########-####-####-####-############-##-##-########] VM <VM> has conflict mac [00:50:##:##:##:##] with existing <VM>, new mac [00:50:##:##:##:##].

Environment

VMware HCX

Cause

Bulk migration from one cluster to another in a single vCenter environment does not retain the MAC address of the VM even if the option is explicitly selected, as the same vCenter cannot register two VMs with the same MAC address, and this is an expected behavior.

Resolution

This is a condition that may occur in a VMware HCX environment.
There is a feature request for upcoming versions for HCX to display a warning when the "Retain MAC" is selected for the Single vCenter Operation.

Additional Information

Understanding VMware HCX Bulk Migration