Virtual machine migration while maintaining live network links

A method comprising:

• employing a virtual machine (VM), on a source host, to maintain a session to communicate network traffic over a communication link during live migration, including:
• responsive to an initiation of a migration of the VM to a destination host during the session:
• converting the VM's memory pages, including a session state, into packets,
• forwarding the packets to the destination host,
• suspending operation of the VM, and
• offloading management of the session to a live migration circuit, and offloading packet processing associated with the session from a central processing unit to the live migration circuit;
• and
• performing, by the live migration circuit, a first plurality of session related functions and a second plurality of session related functions;
• the first plurality of session related function include, while operation of the VM is suspended at least:
• for the communication link associated with the VM to be migrated, determining the session used for packet processing;
• buffering changes to the session state of the determined session;
• maintaining at least a portion of session-related signaling for the determined session;
• and
• dropping network traffic packets over the communication link not associated with keeping the communication link active without terminating the determined session;
• and
• the second plurality of session related functions include, while operation of the VM is resumed, at least:
• transferring the session state changes to a destination live migration circuit at the destination host, wherein the VM is restored at the destination host based on the VM memory pages and the buffered changes to the session state;
• obtaining an indication that the restoring of the VM is complete at the destination host;
• and
• switching the network traffic from the source host to the destination live migration circuit at the destination host.

An apparatus comprising:

• a live migration circuit at a source host couple to a processor, wherein the processor supports operation of a virtual machine (VM) at the source host that maintains a session to communicate network traffic over a communication link during live migration, including:
• responsive to responsive to an initiation of a migration of the VM to a destination host during the session:
• convert the VM's memory pages, including a session state, into packets, forward the packets to the destination host, suspend operation of the VM, and offload management of the session to the live migration circuit, and offload packet processing associated with the session from a central processing unit to the live migration circuit, the offloaded management of the session includes the live migration circuit to perform a first plurality of session related functions and a second plurality of session related functions, the live migration circuit performing:
• the first plurality of session related functions include the live migration circuit to, while operation of the VM is suspended, at least:
• for the communication link associated with the VM to be migrated, determine the session used for packet processing;
• buffer changes to the session state of the determined session;
• maintain at least a portion of session-related signaling for the determined session, wherein maintaining session related signaling includes dropping network traffic packets over the communication link not associated with keeping the communication link active without terminating the determined session;
• perform packet processing for the session from a central processing unit to the live migration circuit;
• and
• the second plurality of session related functions to include the live migration circuit to, while operation of the VM is resumed:
• transfer the session state changes to a destination live migration circuit at the destination host, wherein the VM is restored at the destination host based on the VM memory pages and the buffered changes to the session state;
• obtain an indication that the restore of the VM is complete at the destination host;
• and
• switch the network traffic from the source host to the destination live migration circuit at the destination host.

At least one non-transitory computer readable medium comprising instructions that, when executed, cause processing circuitry to:

• support operation of a virtual machine (VM) at a source host that maintains a session to communicate network traffic over a communication link during live migration, including:
• responsive to an initiation of a migration of the VM to a destination host during the session,:
• convert the VM's memory pages, including a session state, into packets,
• forward the packets to the destination host,
• suspend operation of the VM, and
• offload management of the session to a live migration circuit at the source host and offload packet processing associated with the session from a central processing unit to the live migration circuit,
• wherein the offloaded management of the session includes the live migration circuit to perform a first plurality of session related functions and a second plurality of session related functions;
• the first plurality of session related functions to, while operation of the VM is suspended, at least:
• for the communication link associated with the VM to be migrated, determine the session used for packet processing;
• buffer changes to the session state of the determined session;
• maintain at least a portion of session-related signaling for the determined session, wherein maintaining session related signaling includes dropping network traffic packets over the communication link not associated with keeping the communication link active without terminating the determined session;
• and
• the second plurality of session related functions to, while operation of the VM is resumed, at least:
• transfer the session state changes to a destination live migration circuit at the destination host, wherein the VM is restored at the destination host based on the VM memory pages and the buffered changes to the session state;
• obtain an indication that the restore of the VM is complete at the destination host;
• and
• switch the network traffic from the source host to the destination live migration circuit at the destination host.