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 MAC addresses of the workloads with the active gateway, and wherein the control message instructs the remote gateways to associate the MAC addresses with the backup gateway instead of the active gateway; and

in the backup gateway, receiving network communications directed to one or more of the workloads from one or more of the remote gateways.

2. The method of claim 1 , wherein, responsive to receiving the control message, each of the remote gateways iterates through a MAC address table to change a destination gateway field for each MAC address learned from the active gateway to instead identify 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 first VTEP, an identifier for the second VTEP, and 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 MAC addresses of the workloads with the active gateway, and wherein the control message instructs the remote gateways to associate the MAC addresses with the backup gateway instead of the active gateway; and

receive network communications directed to one or more of the workloads from one or more of the remote gateways.

9. The apparatus of claim 8 , wherein, responsive to receiving the control message, each of the remote gateways iterates through a MAC address table to change a destination gateway field for each MAC address learned from the active gateway to instead identify 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 first VTEP, an identifier for the second VTEP, and 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:

prior to receiving a control message, associating MAC addresses of one or more workloads of an active gateway with the active gateway;

receiving the control message, from a backup gateway, that instructs the remote gateway to associate the MAC addresses with the backup gateway instead of the 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;

in response to the control message, associating the MAC addresses with the backup gateway instead of the active gateway; and

transferring network communications to one or more of the workloads via the backup gateway.

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

iterating through a MAC address table of the remote gateway to change a destination gateway field for each MAC address learned from the active gateway to instead identify 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 first VTEP, an identifier for the second VTEP, and 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.