Incorrect ARP resolution of VMs could occur after VM HA event, resulting in incorrect datapath traffic

Products

• VMware NSX

Issue/Introduction

• A VM HA event occurred and the host where the VM was previously running lost connectivity to the NSX cluster
• The VM MAC address changed but the VM IP address remains the same.
• A restart of the NSX CCP (central control plane) occurs before the host where the VM was previously running reconnects to the CCP.
• The CCP may publish a stale ARP record which maps the VM IP to a stale MAC address resulting in incorrect L2 traffic forwarding on ESX hosts.

An example: After two NSX edge nodes are resized and if the CCP restarts between the operations, the correct MAC address of the VM is not updated properly when CCP comes back up, resulting in stale ARP records in CCP. The BGP/BFD neighborship initiated from edge nodes remains in Init state as the correct MAC of the VM was not updated and neighborship is not established

Environment

VMware NSX-T Data Center
VMware NSX

Resolution

This issue is resolved in VMware NSX 4.2.1.2