Method and system for providing high availability to computer applications

• US 8,402,305 B1
• Filed: 07/20/2010
• Issued: 03/19/2013
• Est. Priority Date: 08/26/2004
• Status: Active Grant

• Current Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Original Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Inventors: Havemose, Allan
• Primary Examiner(s): Baderman, Scott
• Assistant Examiner(s): Leibovich, Yair
• Application Number:
  US12/839,460
• Time in Patent Office: 973 Days
• Field of Search: 714/4, 714/6, 714/10, 714/4.1, 714/4.11, 714/4.12, 714/11, 714/13
• US Class Current: 714/4.12
• CPC Class Codes: G06F 11/0709 in a distributed system consisting of a plurality of standalone computer nodes, e.g. clusters, client-server systems
• CPC Class Codes: G06F 11/1402 Saving, restoring, recovering or retrying
• CPC Class Codes: G06F 11/141 for bus or memory accesses
• CPC Class Codes: G06F 11/1438 Restarting or rejuvenating
• CPC Class Codes: G06F 11/1482 by means of middleware or OS functionality
• CPC Class Codes: G06F 11/20 using active fault-masking, e.g. by switching out faulty elements or by switching in spare elements
• CPC Class Codes: G06F 11/2002 where interconnections or communication control functionality are redundant flexible arrangements for bus networks involving redundancy H04L12/40176
• CPC Class Codes: G06F 11/2023 Failover techniques
• CPC Class Codes: G06F 11/2028 eliminating a faulty processor or activating a spare
• CPC Class Codes: G06F 11/203 using migration
• CPC Class Codes: G06F 11/2046 where the redundant components share persistent storage G06F11/2043 takes precedence
• CPC Class Codes: G06F 11/30 Monitoring
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses

Abstract

A system and method for performing loss-less migration of an application program from a primary node to a backup node. All application state for the application program on the primary node are captured and transmitted to the backup node. TCP/IP connection state is restored for all connections; and internals of the application program are remapped to an operating system and to system libraries on the backup node.

Claims

1. A method for performing loss-less migration of an application program from a primary node with an operating system and one or more networking protocol stacks to a backup node with an operating system and one or more networking protocol stacks, the method comprising:

capturing an application state for the application program on the primary node;

transmitting the application state to the backup node;

restoring a connection state for all connections;

remapping internals of the application program to an operating system on the backup node; and

remapping internals of the application program to system libraries on the backup node;

wherein the application program is selected from the group consisting of a user-space application, an operating system service, a device driver, and a kernel module;

said one or more networking protocol stacks on the primary node and said one or more networking protocol stacks on the backup node require no modifications or reconfigurations for said loss-less migration;

said application runs on the primary node prior to a loss-less migration and on the backup node after a loss-migration, but never on the primary node and the backup node at the same time.

2. The method according to claim 1, further comprising:

recreating an application image from the application state; and

remapping application resources against underlying hardware.

3. The method according to claim 1, wherein the application program is a user space application.

4. The method according to claim 1, wherein said remapping internals of the application program to system libraries requires no source code modifications to said application program.

5. The method according to claim 1, wherein the application program is virtual machine software.

6. The method according to claim 1, further comprising:

disconnecting clients during the loss-less migration; and

accepting client-reconnects on the backup node after completion of the loss-less migration.

7. A non-transitory computer readable storage medium including a computer program having instructions for performing loss-less migration of an application program from a primary node with an operating system and one or more networking protocol stacks to a backup node with an operating system and one or more networking protocol stacks, wherein the computer program performs steps comprising:

capturing an application state for the application program on the primary node;

transmitting the application state to the backup node;

restoring a connection state for all connections;

remapping internals of the application program to an operating system on the backup node; and

remapping internals of the application program to system libraries on the backup node;

wherein the application program is selected from the group consisting of a user-space application, an operating system service, a device driver, and a kernel module;

said one or more networking protocol stacks on the primary node and said one or more networking protocol stacks on the backup node require no modifications or reconfigurations for said loss-less migration;

said application program runs on the primary node prior to a toss-less migration and on the backup node after a loss-migration, but never on the primary node and the backup node at the same time.

8. The non-transitory computer readable storage medium according to claim 7, wherein the computer program further performs steps of:

recreating an application image from the application state; and

remapping application resources against underlying hardware.

9. The non-transitory computer readable storage medium according to claim 7, wherein the application program is a user-space application.

10. The non-transitory computer readable storage medium according to claim 7, wherein the computer program further performs step remapping internals of the application program to system libraries without requiring source code modifications to said application program.

11. The non-transitory computer readable storage medium according to claim 7, wherein the application program is virtual machine software.

12. The non-transitory computer readable storage medium according to claim 7, wherein the computer program further performs steps of:

disconnecting clients during the loss-less migration; and

accepting client-reconnects on the backup node after completion of the loss-less migration.

13. A communications network for performing loss-less migration of an application program from a primary node with an operating system and one or more networking protocol stacks to a backup node with an operating system and one or more networking protocol stacks, the communications network comprising:

a first server structured to run the application program;

a second sewer in communication with the first server, and structured to operate as a back-up server for the first server; and

at least one computer readable storage medium associated with the first server and the second server, the at least one computer readable storage medium including a computer program having instructions for;

capturing an application state for the application program on the primary node;

transmitting the application state to the backup node;

restoring a connection state for all connections;

remapping internals of the application program to an operating system on the backup node; and

remapping internals of the application program to system libraries on the backup node;

wherein the application program is selected from the group consisting of a user-space application, an operating system service, a device driver, and a kernel module;

said one or more networking protocol stacks on the primary node and said one or more networking protocol stacks on the backup node require no modifications or reconfigurations for said loss-less migration;

said application program runs on the primary node prior to a loss-less migration and on the backup node after a loss-migration, but never on the primary node and the backup node at the same time.

14. The communications network according to claim 13, wherein the computer program has further instructions for recreating an application image from the application state.

15. The communications network according to claim 13, wherein the computer program has further instructions for remapping application resources against underlying hardware.

16. The communications network according to claim 13, wherein the application program is a user-space application.

17. The communications network according to claim 13, wherein the computer program has further instructions for remapping internals of the application program to system libraries without requiring source code modifications to said application program.

18. The communications network according to claim 13, wherein the application program is virtual machine software.

19. The communications network according to claim 13, wherein the computer program has further instructions for disconnecting clients during the loss-less migration.

20. The communications network according to claim 13, wherein the computer program has further instructions for accepting client-reconnects on the backup node after completion of the loss-less migration.