CLUSTERING SERVER PROVIDING VIRTUAL MACHINE DATA SHARING

• US 20070088762A1
• Filed: 05/25/2006
• Published: 04/19/2007
• Est. Priority Date: 05/25/2005
• Status: Active Grant

• Current Assignee: Software AG USA Incorporated (Software AG)
• Original Assignee: Orion Letizi, Saravanan Subbiah, Steven Harris, Timothy Eck
• Inventors: Subbiah, Saravanan, Harris, Steven, Eck, Timothy, Letizi, Orion
• Granted Patent: US 7,716,377 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1479 Generic software techniques for error detection or fault masking
• CPC Class Codes: G06F 11/203 using migration
• CPC Class Codes: G06F 16/217 Database tuning G06F16/2282 takes precedence; database performance monitoring G06F11/3409
• CPC Class Codes: G06F 16/24552 Database cache management
• CPC Class Codes: G06F 2209/522 Manager
• CPC Class Codes: G06F 9/445 Program loading or initiating bootstrapping G06F9/4401; security arrangements for program loading or initiating G06F21/57
• CPC Class Codes: G06F 9/45504 Abstract machines for programme code execution, e.g. Java virtual machine [JVM], interpreters, emulators
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes

Abstract

Technology for sharing data among multiple virtual machines in a cluster of virtual machines is disclosed. Each virtual machine identifies “managed” objects of an instance of an application running at the virtual machine. The managed objects are objects for which state information is to be replicated at the other virtual machines in the cluster on which other instances of the application are running. Operations performed by an instance of one application which affect the state of managed objects are detected and distributed. A computer-implemented method for maintaining consistent object states at different virtual machines includes receiving managed object state information from a first virtual machine including a first instance of an application; creating a representation of each of the managed objects; and responsive to the received information, communicating state information to at least a second virtual machine on which a second instance of the application is running to replicate the state information at the second virtual machine.

Claims

1. A computer-implemented method for maintaining consistent data at different virtual machines, comprising:

configuring one or more managed objects;

identifying operations which may affect the one or more managed objects in a first instance of an application on a first virtual machine;

detecting application operations performed on the one or more managed objects by the first instance of the application which affect state information of the managed objects; and

communicating the application operations to a central manager for use in replicating the managed object state information at a second virtual machine.

2. The computer-implemented method of claim 1, wherein:

the step of configuring comprises defining a root object in an object graph at the first virtual machine, the object graph including at least one root object and objects which can be reached from the at least one root object.

3. The computer-implemented method of claim 2, wherein:

the state information is replicated by updating a local instance of the managed object at the second virtual machine with said operations.

4. The computer-implemented method of claim 1, wherein the events comprise method calls.

5. The computer-implemented method of claim 1 wherein the events comprise field set operations.

6. The computer-implemented method of claim 1, wherein the step of identifying includes:

instrumenting byte code of the first instance of the application to perform the steps of identifying and detecting.

7. The computer implemented method of claim 1 wherein the step of identifying includes providing the virtual machine with a facility to incorporate the configuration and output operations affecting the state of a managed object.

8. A computer-implemented method for maintaining consistent data at different virtual machines, comprising:

receiving application operations describing events affecting a local instance of a managed object state from a first virtual machine;

creating a representation of each of the managed objects using the application operations, the representation describing the object state; and

communicating update operations describing the object state information to at least a second virtual machine to replicate the managed object state in a local instance of the managed object on the second virtual machine.

9. The computer-implemented method of claim 8, wherein:

the managed objects are identified by an object graph at the first virtual machine which includes at least one root object and objects reachable from the at least one root object.

10. The computer-implemented method of claim 9, wherein:

the application operations comprise field set operations.

11. The computer-implemented method of claim 8, wherein:

the application operations comprise method calls.

12. The computer-implemented method of claim 8, wherein:

the managed objects are identified and detected by instrumented byte code of the first instance of the application.

13. The computer implemented method of claim 8 wherein the managed objects are identified by the virtual machine having a facility to incorporate the configuration and output operations affecting the state of a managed object.

14. The computer-implemented method of claim 8 further including the steps of:

receiving application operations describing a local instance of a managed object state from the second virtual machine;

updating the representation the managed object; and

communicating update operations to at least the first virtual machine.

15. A computer-implemented method for maintaining consistent data at different virtual machines, comprising:

on a first virtual machine,

identifying operations which may affect state in one or more managed objects in a first instance of an application on a first virtual machine;

detecting application operations performed on the one or more managed objects by the first instance of the application which affect the state information; and

communicating the application operations to a central manager for use in replicating the managed object state information at a second virtual machine, and

on the central manager,

creating a representation of each of the managed objects using the application operations, the representation describing the object state; and

communicating update operations describing the object state information to at least a second virtual machine to replicate the managed object state in a local instance of the managed object on the second virtual machine.

16. The computer-implemented method of claim 15, wherein:

the step of identifying includes defining a root object in an object graph at the first virtual machine which includes at least one root object and objects reachable from the at least one root object.

17. The computer-implemented method of claim 16, wherein:

the state information is replicated by updating local objects at the second virtual machine using the application operations.

18. The computer-implemented method of claim 15, wherein the events comprise method calls.

19. The computer-implemented method of claim 15 wherein the events comprise field set operations.

20. The computer-implemented method of claim 15, wherein the step of identifying comprises:

instrumenting byte code of the first instance of the application to perform the steps of identifying and detecting.

21. The computer implemented method of claim 15 wherein the step of identifying includes providing the virtual machine with a facility to incorporate the configuration and output operations affecting the state of a managed object.