Communication failure after HCX Network Extension appliance vMotion

Products

• VMware HCX

Issue/Introduction

• Communication over HCX network extension fails for a while after NE appliances vMotion.
• Eventually it recovers with no manual operation.
• The NE appliance is connected to vSphere portgroups, not NSX segments.

Environment

VMware HCX

Cause

After vMotion, packets over network extension needs to be forwarded to the new ESXi and the MAC address table entries on the physical switches need to be updated accordingly.
However, current HCX NE appliances do not recognize vMotion and do not send out any packets to update MAC address table.
Thus the MAC address table entries on the physical switches are stale until they expire or packets from the VMs over network extension arrive from the remote site.

Resolution

The issue is fixed in VCF HCX 9.0 after which RARP is sent out on vMotion to update MAC address table.

Additional Information

• Create a VM-Host Affinity Rule to ensure the HCX NE VM remains on the designated host.
• Or Avoid using DRS in fully automated mode; instead, use manual or partially automated mode to suppress automatic vMotion activity triggered by DRS. For more information, refer to the DRS Automation documentation.
  • Note: You need to configure it again after redeploy and upgrade.
• In case of ESXi maintenance, configure HA and shutdown the NE appliances rather than vMotion.
• It immediately recovers communication over L2 extension to send some packets from the remote site VMs to the local site.