# Patent

## Title
Application recovery

## Abstract

A method includes, in a grid network, querying a grid manager for assignment of a resource for execution of an application, the query including a grid application recovery request, assigning a resource having a grid application recovery service in response to the grid application recovery request, establishing a communication channel between the assigned resource and a recovery application on a recovery resource, and storing recovery information over the communication channel on the recovery resource during execution of the application.

## Background
TECHNICAL FIELD
The present invention relates to data processing by digital computer, and more particularly to application recovery.
BACKGROUND
Grid computing is a form of distributed system wherein computing resources are shared across networks. Grid computing enables the selection, aggregation, and sharing of information resources resident in multiple administrative domains and across geographic areas. These information resources are shared, for example, based upon their availability, capability, and cost, as well as a user's quality of service (QoS) requirements. Grid computing can mean reduced cost of ownership, aggregated and improved efficiency of computing, data, and storage resources, and enablement of the creation of virtual organizations for applications and data sharing.
SUMMARY
The present invention provides methods and apparatus, including computer program products, for application recovery in a grid network.
In one aspect, the invention features a method including in a grid network, querying a grid manager for assignment of a resource for execution of an application, the query including a grid application recovery request, assigning a resource having a grid application recovery service in response to the grid application recovery request, establishing a communication channel between the assigned resource and a recovery application on a recovery resource, and storing recovery information over the communication channel on the recovery resource during execution of the application.
In embodiments, the grid application recovery request can be an extended markup language (XML) file describing which parts of the application are to be saved during execution, how often the parts are to be saved, and a description of the communication channel.
Establishing can include passing the XML file to the recovery application on the recovery resource. Storing can include interrupting the execution of the application in accordance with instructions contained in the XML file, saving the parts of the executing application by the recovery application on the recovery resource as indicated by the instructions in the XML file and resuming the execution of the application.
The method can include restoring parameters stored in the recovery information to the application in the event of a premature termination of the execution of the application, and restarting the execution of the application.
The grid application recovery service can be a web service executing inside a grid container on the recovery resource.
Embodiments of the invention may have one or more of the following advantages.
Application developers do not have to implement a functionality that saves a state of their applications regularly.
Application developers do not have to be concerned about which location the persistent data has to be stored or how their applications get the correct parameters at startup to be able to recover from an unplanned and premature application execution.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.



DESCRIPTION OF DRAWINGS
FIG. 1 is block diagram.
FIG. 2 is a flow diagram.



Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
As shown in FIG. 1, a grid network 10 in accordance with one embodiment of the invention includes a number of interconnected grid compute nodes 12, 14, 16, 18. In an example, the grid network 10 is implemented as a client-server network. Client/server describes a relationship between two computer programs in which one program, the client, makes a service request from another program, the server, which fulfills the request. Although the client/server idea can be used by programs within a single computer, it is a more important idea in a network, such at network 10. In a network, the client/server model provides a convenient way to interconnect programs that are distributed efficiently across different locations.
In the client/server model, one server, sometimes called a daemon, is activated and awaits client requests. Typically, multiple client programs share the services of a common server program. Both client programs and server programs are often part of a larger program or application. Relative to the Internet, a Web browser is a client program that requests services from a Web server in another computer somewhere on the Internet.
Each of the grid compute nodes, grid compute node 18 for example, can include a processor 30 and a memory 32. Memory 32 includes a grid manager 34 and an operating system (OS) 36, such as Unix, Linux or Windows.
Each of the grid compute nodes 12, 14, 16, and 18 include grid-enabled applications capable of executing in response to a request to perform a task. In the event of a crash or premature termination, some of the grid-enabled applications require that their current state of execution and intermediate results be preserved so as not to waste valuable processing power and time before the premature termination. Some of the grid compute nodes, such as grid compute node 18, include recovery service 38 residing in memory 32. Grid compute nodes in network 10 that include a recovery service are generally referred to as recovery resources. In one particular example, a recovery service resides in all of the grid compute nodes 12, 14, 16, and 18. In another particular example, the recovery service resides in one or more grid compute nodes in network 10.
In one embodiment, the recovery service 38 receives and maintains an application recovery file 40, such as an extended markup language (XML) file, from a grid-enabled application upon execution initiation. The application recovery file 40 can be received as metadata in request to execute an application in a grid compute node.
The application recovery file 40 stores the part or parts of a specific application to save, and how often the part or parts are to be saved, during execution. The application recovery file 40 also includes a description of a communications channel that is used to communicate between an application executing in a grid compute node and the recovery service 38.
The communications channel allows an external program (e.g., recovery service 38) to interrupt and continue executing application. In a particular example, this is implemented by having each application listen to a specific TCP/IP port that is specified at startup. In another particular example, an application exposes a web service that is used to send commands to the recovery service 38.
After an application execution is initiated, the recovery service 38 interrupts the executing application over the communications channel, obtains needed recovery information, saves the recovery information, and signals the application to continue. Recovery information can include, for example, saving certain files or certain data residing in a database.
More specifically, an application ready to execute in the grid network 10 queries a grid manager 34 or grid application scheduler to receive a list grid compute nodes available to handle the application execution. In the query (e.g., using the metadata) the application identifies itself to the grid manager as an application needing a grid-managed application recovery service. The application request also defines (e.g., using metadata) at which place an XML file can be found (e.g., by specifying a universal resource locator (URL)) and a description of a communications channel.
The grid manager 34 selects only grid compute nodes with an application recovery service in place. In embodiments, the application recovery service 34 is a grid service or web service running inside a grid container on a grid compute node, or an application running on a grid compute node.
The grid manager 34 employs the grid compute node and when the application is started an XML file passed to the application recovery service 38 that will track the application.
Once the application starts, the grid manager 34 sends a connect command to the application recovery service 38 and the application recovery service 38 connects to the application using the communication channel specified in the XML file.
As specified in the XML file, the application recovery service 38 interrupts the application at certain times and performs a save operation as specified in the XML file. After a successful save operation the application recovery service 38 sends a continue to the application.
In the application fails (e.g., crashes or fails to respond to an interrupt message in a specified amount of time), the application recovery service 38 acts according to the XML file, e.g., put files to certain locations or restore data in a database. The application is restarted.
As shown in FIG. 2, an application recovery process 100 includes, in a grid network, querying (102) a grid manager for assignment of a resource (e.g., grid compute node) for execution of an application, the query including a grid application recovery request. The grid application recovery request can include an extended markup language (XML) file describing which parts of the application are to be saved during execution, how often the parts are to be saved, and a description of a communication channel.
Process 100 assigns (104) a resource (e.g., grid compute node) having a grid application recovery service in response to the grid application recovery request. In a particular example, the grid application recovery service is a web service executing inside a grid container on a recovery resource.
Process 100 establishes (106) the communication channel between the assigned resource and a recovery application on a recovery resource. In a particular example, establishing (106) includes passing the XML file to the recovery application on the recovery resource.
Process 100 stores (108) recovery information over the communication channel on the recovery resource during execution of the application. Storing (108) includes interrupting the execution of the application in accordance with instructions contained in the XML file, saving the parts of the executing application by the recovery application on the recovery resource as indicated by the instructions in the XML file and resuming the execution of the application.
Process 100 restores (110) parameters stored in the recovery information to the application in the event of a premature termination of the execution of the application.
The invention can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. The invention can be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.
Method steps of the invention can be performed by one or more programmable processors executing a computer program to perform functions of the invention by operating on input data and generating output. Method steps can also be performed by, and apparatus of the invention can be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).
Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in special purpose logic circuitry.

## Claims

1. A computer-implemented method comprising:
in a grid network, querying a grid manager for assignment of a resource for execution of an application, the query including a grid application recovery request;
assigning a resource having a grid application recovery service in response to the grid application recovery request;
establishing a communication channel between the assigned resource and a recovery application on a recovery resource; and
storing recovery information over the communication channel on the recovery resource during execution of the application,
wherein the grid application recovery request reflects at least one of parts of the application to be saved during execution, how often selected parts of the application are to be saved during execution, and a description of the communication channel.

2. The computer-implemented method of claim 1 wherein the grid application recovery request is an extended markup language (XML) file.

3. The computer-implemented method of claim 2 wherein establishing comprises passing the XML file to the recovery application on the recovery resource.

4. The computer-implemented method of claim 3 wherein storing comprises:
interrupting the execution of the application in accordance with instructions contained in the XML file;
saving the parts of the executing application by the recovery application on the recovery resource as indicated by the instructions in the XML file; and
resuming the execution of the application.

5. The computer-implemented method of claim 1 further comprising restoring parameters stored in the recovery information to the application in the event of a premature termination of the execution of the application.

6. The computer-implemented method of claim 5 further comprising restarting the execution of the application.

7. The computer-implemented method of claim 1 wherein the grid application recovery service is a web service executing inside a grid container on the recovery resource.

8. A computer-readable storage device comprising instructions for causing a processor to:
query a grid manager for assignment of a resource for execution of an application, the query including a grid application recovery request;
assign a resource having a grid application recovery service in response to the grid application recovery request;
establish a communication channel between the assigned resource and a recovery application on a recovery resource; and
store recovery information over the communication channel on the recovery resource during execution of the application,
wherein the grid application recovery request reflects at least one of parts of the application to be saved during execution, how often selected parts of the application are to be saved during execution, and a description of the communication channel.

9. The computer-readable storage device of claim 8 wherein the grid application recovery request is an extended markup language (XML) file.

10. The computer-readable storage device of claim 9 wherein establishing comprises passing the XML file to the recovery application on the recovery resource.

11. The computer-readable storage device of claim 10 wherein storing comprises:
interrupting the execution of the application in accordance with instructions in the XML file;
saving the parts of the executing application by the recovery application on the recovery resource as indicated by the instructions in the XML file; and
resuming the execution of the application.

12. The computer-readable storage device of claim 8 further comprising instructions to restore parameters stored in the recovery information to the application in the event of a premature termination of the execution of the application.

13. The computer-readable storage device of claim 12 further comprising instructions to restart the execution of the application.

14. The computer-readable storage device of claim 8 wherein the grid application recovery service is a web service executing inside a grid container on the recovery resource.

15. A system in a grid compute network comprising:
a processor;
means for querying a grid manager for assignment of a resource for execution of an application, the query including a grid application recovery request;
means for assigning a resource having a grid application recovery service in response to the grid application recovery request;
means for establishing a communication channel between the assigned resource and a recovery application on a recovery resource; and
means for storing recovery information over the communication channel on the recovery resource during execution of the application,
wherein the grid application recovery request reflects at least one of parts of the application to be saved during execution, how often selected parts of the application are to be saved during execution, and a description of the communication channel.

16. The system of claim 15 wherein the grid application recovery request is an extended markup language (XML) file.

17. The system of claim 16 wherein the means for establishing comprises passing the XML file to the recovery application on the recovery resource.

18. The system of claim 17 wherein the means for storing comprises:
interrupting the execution of the application in accordance with instructions in the XML file;
saving the parts of the executing application by the recovery application on the recovery resource as indicated by the instructions in the XML file; and
resuming the execution of the application.

19. The system of claim 15 further comprising means for restoring parameters stored in the recovery information to the application in the event of a premature termination of the execution of the application.

20. The system of claim 19 further comprising means for restarting the execution of the application.

21. The system of claim 15 wherein the grid application recovery service is a web service executing inside a grid container on the recovery resource.

22. A computer-implemented method comprising:
receiving, by a grid manager in a grid network, a query for assignment of a resource for execution of an application, the query including a grid application recovery request;
assigning a resource having a grid application recovery service in response to the grid application recovery request; and
establishing a communication channel between the assigned resource and a recovery application on a recovery resource;
wherein recovery information is stored over the communication channel on the recovery resource during execution of the application, and
wherein the grid application recovery request reflects at least one of parts of the application to be saved during execution, how often selected parts of the application are to be saved during execution, and a description of the communication channel.

23. A computer-readable storage device comprising instructions for causing a processor in a grid manager to:
receive a query for assignment of a resource for execution of an application, the query including a grid application recovery request;
assign a resource having a grid application recovery service in response to the grid application recovery request; and
establish a communication channel between the assigned resource and a recovery application on a recovery resource;
wherein recovery information is stored over the communication channel on the recovery resource during execution of the application, and
wherein the grid application recovery request reflects at least one of parts of the application to be saved during execution, how often selected parts of the application are to be saved during execution, and a description of the communication channel.

24. A system in a grid compute network, the system comprising:
a processor;
means for receiving, by a grid manager, a query for assignment of a resource for execution of an application, the query including a grid application recovery request;
means for assigning a resource having a grid application recovery service in response to the grid application recovery request; and
means for establishing a communication channel between the assigned resource and a recovery application on a recovery resource;
wherein recovery information is stored over the communication channel on the recovery resource during execution of the application, and
wherein the grid application recovery request reflects at least one of parts of the application to be saved during execution, how often selected parts of the application are to be saved during execution, and a description of the communication channel.