System and method for virtual server migration across networks using DNS and route triangulation

• US 7,966,364 B2
• Filed: 07/28/2008
• Issued: 06/21/2011
• Est. Priority Date: 07/26/2007
• Status: Expired due to Fees

• Current Assignee: Northeastern University
• Original Assignee: Northeastern University
• Inventors: Faber, Nathan, Sundaram, Ravi
• Primary Examiner(s): Winder; Patrice L
• Assistant Examiner(s): Golabbakhsh; Ebrahim
• Application Number:
  US12/180,813
• Publication Number:
  US 20090198817A1
• Time in Patent Office: 1,058 Days
• Field of Search: 709/227, 709/201, 709/220
• US Class Current: 709/201
• CPC Class Codes: H04L 61/5076 Update or notification mechanisms, e.g. DynDNS
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/63 Routing a service request depending on the request content or context

Abstract

A first virtual server is moved from a first network location to a second network location without interrupting service to users of the first virtual server. The state and data of the first virtual server are copied and transmitted to the second network location to create a copy of the first virtual server. The first virtual server copy is then updated to duplicate the first virtual server and all connections or packets directed to the first virtual server are intercepted and directed to the first virtual server copy at the second network location. A DNS entry for the symbolic name of the first virtual server is updated to reflect a shortened TTL value and then the address field of the DNS entry is set to the address of the first virtual server copy after the changeover and subsequent connections are directed to the first virtual server copy.

Claims

1. A method of moving operation of a first virtual server from a first network location having a first network address to a second network location having a second network address different from the first network address, the method comprising:

copying first operating data representing a first state of operation of the first virtual server at a first time;

establishing a second virtual server in the first state of operation at the second network location using the copied first operating data of the first virtual server;

subsequent to establishing the second virtual server in the first state of operation, pausing operation of the first virtual server and copying additional operating data representing a second state of operation of the first virtual server;

while the first virtual server is paused, establishing the second virtual server in the second state of operation using the copied additional operating data of the first virtual server;

diverting data addressed to the first virtual server at the first network address to the second virtual server at the second network address starting at a predetermined time after establishing the second virtual server in the second state of operation; and

the second virtual server processing the diverted data and sending a response back to an origin of the diverted data,

wherein the response from the second virtual server appears, to the origin of the diverted data, to have come from the first virtual server located at the first network address.

2. The method of claim 1, further comprising:

updating a DNS entry for a first symbolic name associated with the first virtual server.

3. The method of claim 2, wherein updating the DNS entry further comprises:

setting an expiration value for the first network address associated with the first virtual server.

4. The method of claim 2, wherein updating the DNS entry comprises:

setting a network address value associated with the first symbolic name to the second network address of the second virtual server.

5. A method of moving operation of a first virtual server from a first network location having a first network address to a second network location having a second network address different from the first network address, the method comprising:

copying first operating data representing a first state of operation of the first virtual server at a first time;

establishing a second virtual server in the first state of operation at the second network location using the copied first operating data of the first virtual server;

subsequent to establishing the second virtual server in the first state of operation, pausing operation of the first virtual server and copying additional operating data representing a second state of operation of the first virtual server subsequent to pausing the first virtual server;

establishing, subsequent to pausing the first virtual server, the second virtual server in the second state of operation at the second network location using the copied additional operating data, the second virtual server being a copy of the first virtual server subsequent to being paused;

starting operation of the second virtual server subsequent to the second virtual server being established in the second state of operation;

forwarding, to the second virtual server, data addressed to the first network address of the first virtual server subsequent to the second virtual server starting operation;

returning a response from the second virtual server to an origin of the forwarded data, the returned response appearing, to the origin, to have come from the first virtual server at the first network address; and

modifying, at a time prior to suspending operation of the first virtual server, a DNS entry associated with a symbolic name of the first virtual server.

6. The method of claim 5, wherein modifying the DNS entry comprises:

setting an expiration field to expire at a time prior to suspending operation of the first virtual server.

7. The method of claim 5, wherein modifying the DNS entry comprises:

setting a network address field to the second network address associated with the second virtual server after starting operation of the second virtual server.

8. The method of claim 5, wherein forwarding data addressed to the first network address comprises:

forwarding data only for a connection to the first virtual server established prior to suspending operation of the first virtual server.

9. The method of claim 5, wherein forwarding data addressed to the first network address comprises:

forwarding data received within a predetermined time period of starting operation of the second virtual server.

10. The method of claim 5, further comprising:

no longer forwarding data directed to the first network address at a predetermined time after starting operation of the second virtual server.

11. The method of claim 5, further comprising:

measuring an amount of data directed to the first network address; and

no longer forwarding data directed to the first network address when the measured amount of data is below a predetermined threshold.

12. The method of claim 11, wherein the predetermined threshold comprises at least one of:

a predetermined amount of data;

a predetermined amount of data received over a predetermined amount of time; and

a predetermined rate of data.

13. A system for moving operation of a first virtual server from a first network location having a first network address to a second network location having a second network address different from the first network address, the system comprising:

means for copying first operating data representing a first state of operation of the first virtual server at a first time;

means for establishing a second virtual server in the first state of operation at the second network location using the copied first operating data of the first virtual server;

means for, subsequent to the second virtual server being established, pausing operation of the first virtual server and copying additional operating data representing a second state of operation of the first virtual server;

means for, while the first virtual server is paused, establishing the second virtual server in the second state of operation using the copied additional operating data of the first virtual server;

means for diverting data addressed to the first virtual server at the first network address to the second virtual server at the second network address starting at a predetermined time after establishing the second virtual server in the second state of operation; and

means for the second virtual server processing the diverted data and sending a response back to an origin of the diverted data,

wherein the response from the second virtual server appears, to the origin of the diverted data, to have come from the first virtual server located at the first network address.

14. The system of claim 13, further comprising:

means for updating a DNS entry for a first symbolic name associated with the first virtual server; and

means for setting an expiration value in the DNS entry for the first network address associated with the first virtual server.