Fast relearning of workload MAC addresses multi-homed to active and backup gateways

1. A method of fast re-learning workload media access control (MAC) addresses, the method comprising:

determining that a backup gateway should begin handling communications exchanged with one or more workloads of an active gateway for a logical network;

transferring a control message to one or more remote gateways in communication with the backup gateway, wherein, prior to receiving the control message, the one or more remote gateways associates first MAC addresses of the workloads with the active gateway, and wherein the control message instructs the remote gateways to flush the first MAC addresses; and

exchanging network communications between the workloads and the remote gateways through the backup gateway, wherein the remote gateways associate the first MAC addresses with the backup gateway in response to the network communications.

2. The method of claim 1 , wherein the remote gateways associate the first MAC addresses with the backup gateway by creating an entry in a MAC address table for each MAC address of the first MAC addresses, wherein each entry includes a destination gateway field that indicates the backup gateway.

3. The method of claim 1 , wherein the active gateway comprises a first Virtual Tunnel Endpoint (VTEP) and the backup gateway comprises a second VTEP.

4. The method of claim 3 , wherein the control message indicates an identifier for the logical network.

5. The method of claim 1 , wherein the control message comprises a control packet having an Operations, Administration and Maintenance (OAM) bit set.

6. The method of claim 1 , wherein the logical network comprises a nvo3 (Network Virtualization Overlays) type logical network.

7. The method of claim 6 , wherein the logical network is implemented using Geneve or Virtual Extensible Local Area Networking (VXLAN).

8. An apparatus implementing a backup gateway for fast re-learning workload media access control (MAC) addresses, the apparatus comprising:

one or more computer readable storage media;

a processing system operatively coupled with the one or more computer readable storage media; and

program instructions stored on the one or more computer readable storage media that, when read and executed by the processing system, direct the processing system to:

determine that a backup gateway should begin handling communications exchanged with one or more workloads of an active gateway for a logical network;

transfer a control message to one or more remote gateways in communication with the backup gateway, wherein, prior to receiving the control message, the one or more remote gateways associates first MAC addresses of the workloads with the active gateway, and wherein the control message instructs the remote gateways to flush the first MAC addresses; and

exchange network communications between the workloads and the remote gateways through the backup gateway, wherein the remote gateways associate the first MAC addresses with the backup gateway in response to the network communications.

9. The apparatus of claim 8 , wherein the remote gateways associate the first MAC addresses with the backup gateway by creating an entry in a MAC address table for each MAC address of the first MAC addresses, wherein each entry includes a destination gateway field that indicates the backup gateway.

10. The apparatus of claim 8 , wherein the active gateway comprises a first Virtual Tunnel Endpoint (VTEP) and the backup gateway comprises a second VTEP.

11. The apparatus of claim 10 , wherein the control message indicates an identifier for the logical network.

12. The apparatus of claim 8 , wherein the control message comprises a control packet having an Operations, Administration and Maintenance (OAM) bit set.

13. The apparatus of claim 8 , wherein the logical network comprises a nvo3 (Network Virtualization Overlays) type logical network.

14. The apparatus of claim 13 , wherein the logical network is implemented using Geneve or Virtual Extensible Local Area Networking (VXLAN).

15. A method of fast re-learning workload media access control (MAC) addresses, the method comprising:

in a remote gateway, receiving a control message, from a backup gateway, that instructs the remote gateways to flush first MAC addresses associated with an active gateway, wherein the backup gateway transfers the control message in response to determining that the backup gateway should begin handling communications exchanged with one or more workloads of the active gateway for a logical network;

exchanging network communications between the remote gateway and the workloads through the backup gateway; and

associating the first MAC addresses with the backup gateway in response to the network communications.

16. The method of claim 15 , wherein associating the first MAC addresses with the backup gateway comprises:

creating an entry in a MAC address table for each MAC address of the first MAC addresses, wherein each entry includes a destination gateway field that indicates the backup gateway.

17. The method of claim 15 , wherein the active gateway comprises a first Virtual Tunnel Endpoint (VTEP) and the backup gateway comprises a second VTEP.

18. The method of claim 17 , wherein the control message indicates an identifier for the logical network.

19. The method of claim 15 , wherein the control message comprises a control packet having an Operations, Administration and Maintenance (OAM) bit set.

20. The method of claim 15 , wherein the logical network comprises a nvo3 (Network Virtualization Overlays) type logical network.