Error: Failed to refresh gateway MAC, vmknic [vmkX] : Status pending in NSX Transport Nodes

Products

• VMware NSX

Issue/Introduction

• ESXi host has NSX installed.
• The IP pool for the TEP has a Gateway configured.
• NSX Transport Node agents (NSX_PROXY, NSX_PLATFORM_CLIENT, or NSX_CFGAGENT) intermittently flap between Up and Degraded status. This behavior is often observed in newly deployed or upgraded VCF 9.1 environments.
• The following warnings appear repeatedly in /var/log/vmkernel.log: 
  
  WARNING: vdl2: VDL2IFMVMKGatewayMACResolveCB:####: [nsx@6876 comp="nsx-esx" subcomp="vdl2-####"]Failed to refresh gateway MAC, vmknic [vmk10] : Status pending
  
  
• Command net-vdl2 -l shows GW MAC: ff:ff:ff:ff:ff:ff.
  
  
  

  [root@<hostname>:~] net-vdl2 -l
  Global States:
          Control Plane Out-Of-Sync:      No
          VXLAN UDP Port: 4789
          Geneve UDP Port:        6081
  NSX VDS:        <VDS Name>
          VDS ID: <ID>
          MTU:    8900
          Segment ID:     <ID>
          AddrType6:      Not Configured
          Segment ID6:    ::
          Transport VLAN ID:      <VLAN ID>
          VTEP Count:     2
          Forwarding Mode:        IPv4_ONLY
          CDO status:     enabled (deactivated)
                  VTEP Interface: vmk10
                          DVPort ID:      <ID>
                          Switch Port ID: <PORT ID>
                          Endpoint ID:    0
                          VLAN ID:        <VLAN ID>
                          Label:          <VNI ID>
                          Uplink Port ID: <UPLINK PORT ID>
                          Is Uplink Port LAG:     No
                          IP:             <VTEP IP ADDRESS>
                          Netmask:        255.255.255.0
                          Segment ID:     <SEGMENT ID>
                          IPv6:           ::
                          Prefix Length:  0
                          Segment ID6:    ::
                          GW IP:          <VTEP GW IP ADDRESS>
                          GW MAC:      ff:ff:ff:ff:ff:ff <<<<<<<<<<<<<<<
  

  
  
  

Environment

• VMware Cloud Foundation
• VMware NSX 

Cause

This message occurs when the MAC address of the IP address set as the Gateway for the TEP IP pool can not be resolved.

Resolution

1. Verify if routing is required for TEP traffic. Overlay communication within the same Layer 2 segment does not require a gateway.
2. If routing is not required:
   1. Navigate to NSX Manager > Networking > IP Address Pools.
   2. Edit the TEP IP Pool.
   3. Remove the Gateway IP address.
   4. Save the changes. The vdl2 module stops attempting ARP resolution immediately.
3. If routing is required:
   1. Verify the physical network configuration on the TEP VLAN.
   2. Ensure the gateway IP is correct and responding to ARP requests.
   3. Confirm that jumbo frames (MTU 1600+) are configured end-to-end.

•  

Additional Information

In network configurations where overlay communication does not need to pass through any Gateway router, such as, when all TEPs are in the same network segment, inability to resolve the gateway MAC does not impact overlay communication.

For more details on managing TEP IP Pools, refer to the VMware NSX Documentation: Create an IP Pool for Tunnel Endpoint IP Addresses. For assistance, see Contact Broadcom Support.