Long Distance Virtual Machine Migration

• US 20100287548A1
• Filed: 05/06/2009
• Published: 11/11/2010
• Est. Priority Date: 05/06/2009
• Status: Active Grant

• Current Assignee: Vmware LLC (Broadcom, Inc.)
• Original Assignee: VMware, Inc. (Broadcom, Inc.)
• Inventors: PARIENTE, Mark, LAMBETH, Andrew, ZHOU, Shudong
• Granted Patent: US 8,429,647 B2
• Time in Patent Office: Days
• US Class Current: 718/1
• CPC Class Codes: G06F 9/4856 resumption being on a different machine, e.g. task migration, virtual machine migration G06F9/5088 takes precedence
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 61/2514 between local and global IP addresses

Abstract

Methods, systems and computer programs for migrating a virtual machine (VM) executing on a first host to a second host are presented, where the first host and the second are on different networks. One embodiment of a method includes assigning to the VM a VM address (VMA) belonging to a VM network and publishing a first route to an associated network (AN) via a first virtual router executing on the first host. The method further includes migrating the VM from the first host to the second host, the VM maintaining the assigned VMA after migrating, and publishing a second route to the AN via a second virtual router executing on the second host. The first and second virtual routers have addresses belonging to the VM network, and network packets to and from the VM flow through the virtual router where the VM is executing. A temporary tunnel between the virtual routers allows traffic to flow to the VM while the new route to AN is propagated throughout the network. The use of the associated network, which is associated with the VM, and the publishing of a new route to the VM allow the VM to keep the original VMA network address after the migration.

Claims

1. A method for migrating a virtual machine (VM) executing on a first host on a first network to a second host on a second network different from the first network, the method comprising:

assigning to the VM a VM address (VMA) belonging to a VM network;

publishing a first route to an associated network (AN) via a first virtual router executing on the first host;

migrating the VM from the first host to the second host, the VM maintaining the assigned VMA after migrating; and

publishing a second route to the AN via a second virtual router executing on the second host, the first and second virtual routers having addresses belonging to the VM network, wherein network packets to and from the VM flow through the virtual router where the VM is executing.

2. The method of claim 1, wherein the first network, the second network, the associated network AN, and the VM network have four different network addresses,

wherein outbound packets originating at the VM flow to the virtual router on the host where the VM is executing, the outbound packets having VMA as a source address, the first and the second virtual router replace the outbound packets source addresses with a VM outside address before forwarding the outbound packets, the VM outside address belonging to the AN network.

3. The method of claim 2, wherein the first and second virtual routers provide Network Address Translation (NAT) services, wherein inbound packets with a destination address equal to the VM outside address and arriving at the virtual router where the VM is executing are forwarded to the VM after replacing the destination address with VMA.

4. The method of claim 2, wherein assigning VMA further includes,

providing Dynamic Host Configuration Protocol (DHCP) support on the VM network by the first virtual router;

and

assigning the VMA to the VM with the DHCP protocol.

5. The method of claim 1, wherein the AN network has associated an internet protocol (IP) subnet mask of 255.255.255.255 (/32).

6. The method of claim 1, wherein a cost used when publishing the second route is lower than a cost used when publishing the first route.

7. The method of claim 1, wherein migrating the VM further includes,

creating a network tunnel between the first and the second virtual routers, wherein packets destined to the VM and received at the virtual router on the host where the VM is not executing are forwarded through the network tunnel.

8. The method of claim 7, further including,

terminating the network tunnel after conditions for terminating the tunnel are met, wherein one or more conditions are selected from the group consisting of a timeout is reached, a time between packets in the tunnel exceeds a certain value, a timeout for not observing any more packets, and active probing of the routing infrastructure.

9. The method of claim 8, further including,

terminating the first virtual router after terminating the network tunnel.

10. The method of claim 1, further including,

creating a group of VMs executing on the first host, the VM belonging to the group of VMs, wherein each VM in the group of VMs has an address belonging to the VM network;

and

creating a network tunnel between the first and the second virtual routers, wherein packets destined to a particular VM from the group and received at the virtual router on the host where the particular VM is not executing are forwarded through the network tunnel.

11. The method of claim 10, further including,

migrating each VM in the group from the first host to the second host;

and

terminating the network tunnel after all the VMs have moved and when the network tunnel is not needed for the group of VMs to maintain network connectivity.

12. The method of claim 10, further including,

fragmenting the AN network into a plurality of networks,

assigning to each VM in the group a different network from the plurality of networks,

publishing routes to the plurality of networks via the first router except for the network assigned to the VM that moved to the second host,

publishing a route to the network assigned to the VM that moved to the second host via the second router, and

terminating the network tunnel when the network tunnel is not needed to maintain network connectivity for the VM that moved to the second host.

13. The method of claim 1, wherein the associated network is the same as the VM network.

14. A system for migrating a virtual machine (VM) from a first computer on a first network to a second computer on a second network, the system comprising:

a first virtual router executing in the first computer; and

a second virtual router created in the second computer after determining that the VM is migrating to the second computer;

wherein the first and second virtual routers publish an address of an associated network (AN) that is linked to the VM to allow the VM to have a same network address while executing on the first and on the second computer;

wherein the first network, the second network, and the AN network have different network addresses;

wherein network packets to and from the VM flow through the virtual router where the VM is executing.

15. The system of claim 14, wherein the network address used by the VM is not part of the first network, nor the second network, nor the AN network.

16. The system of claim 15, wherein the first and second virtual routers provide Network Address Translation (NAT) services to assign the network address used by the VM.

17. The system of claim 14, wherein the published address of AN occupies the whole space reserved for a network address, wherein the published address of AN leaves no room for a node address in the AN network.

18. The system of claim 17, wherein the networking layer protocol is Internet Protocol (IP) address version 4, wherein the first and second virtual routers publish the AN with a subnet mask of 255.255.255.255.

19. The system of claim 14, further including,

additional virtual routers in the first computer created for the VM, the additional virtual routers corresponding to additional IP addresses of the VM.

20. A computer program embedded in a computer-readable storage medium, when executed by one or more processors, for migrating a virtual machine (VM) executing on a first host on a first network to a second host on a second network, the computer program comprising:

program instructions for assigning to the VM a VM address (VMA) belonging to a VM network;

program instructions for publishing a first route to an associated network (AN) via a first virtual router executing on the first host, the first network, the second network, the associated network AN, and the VM network having four different network addresses;

program instructions for migrating the VM from the first host to the second host, the VM maintaining the VMA after the migrating; and

program instructions for publishing a second route to AN via a second virtual router executing on the second host, the first and second virtual routers having addresses belonging to the VM network, wherein network packets to and from the VM flow through the virtual router where the VM is executing.