RESOURCE AFFINITY IN A DYNAMIC RESOURCE POOL

• US 20150215229A1
• Filed: 01/29/2014
• Published: 07/30/2015
• Est. Priority Date: 01/29/2014
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: XU, QI, SHIPP, NEIL L.
• Granted Patent: US 10,097,628 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/00 Information retrieval; Database structures therefor; File system structures therefor
• CPC Class Codes: H04L 67/1027 Persistence of sessions during load balancing
• CPC Class Codes: H04L 67/1031 Controlling of the operation of servers by a load balancer, e.g. adding or removing servers that serve requests

Abstract

Techniques disclosed herein describe methods for achieving resource affinity and scalability in dynamic environments by calculating the modulus of a numeric request identifier against a fixed selection of numbers. Using the proposed techniques yields a numeric request identifier and resource identifier combination that ensures a given resource possesses the unique state applicable to that user'"'"'s request. Using a fixed selection of numbers thus maintains resource affinity while achieving scalability as resources are added to or subtracted from a pool of resources.

Claims

1. A method of facilitating resource affinity in a dynamic resource pool, the method comprising:

mapping a request to an associated resource of a dynamic number of resources by calculating a modulus on a request identifier with at least a first number in a predefined list of numbers to generate a resource identifier identifying the associated resource.

2. The method of claim 1, further comprising performing a hash function of a request key to generate the request identifier.

3. The method of claim 2, wherein the wherein the request key comprises a string.

4. The method of claim 1, wherein the predefined list of numbers consists of prime numbers.

5. The method of claim 1, wherein the predefined list of numbers is arranged with numbers in descending order.

6. The method of claim 1, wherein the largest number in the predefined list is selected to be equal to or greater than an expected maximum number of resources in the dynamic resource pool.

7. The method of claim 1, wherein when calculating the modulus of the request identifier with at least the first number in the predefined list of numbers, the predefined list of numbers is traversed sequentially until a resource identifier to a valid available associated resource is achieved.

8. The method of claim 7, wherein a next number in the predefined list is not used until a current number does not return the resource identifier to the valid available associated resource.

9. The method of claim 1, further comprising maintaining a resource list;

and determining a status of a particular resource of the dynamic number of resources by reviewing the resource list based on the resource identifier before communicating with the associated resource.

10. The method of claim 1, further comprising:

communicating with the associated resource identified by the resource identifier to determine its availability; and

in response to receiving a status of available, communicating the request to the associated resource;

in response to receiving a status of not available, communicating with a next associated resource identified by another resource identifier generated by calculating the modulus on the request identifier with a next number in the predefined list of numbers.

11. An apparatus comprising:

one or more computer readable storage media;

a predefined list of numbers stored on at least one of the one or more computer readable storage media; and

program instructions stored on at least one of the one or more computer readable media that, when executed by a processing system, direct the processing system to;

map a request to an associated resource of a dynamic number of resources by calculating a modulus on a request identifier with at least a first number in the predefined list of numbers to generate a resource identifier identifying the associated resource.

12. The apparatus of claim 11, further comprising instructions stored on at least one of the one or more computer readable media that, when executed by the processing system, direct the processing system to:

in response to receiving a request, perform a hash function of a request key of the request to generate the request identifier.

13. The apparatus of claim 11, wherein the predefined list of numbers consists of prime numbers.

14. The apparatus of claim 11, wherein the predefined list of numbers is arranged with numbers in descending order.

15. The apparatus of claim 11, wherein the largest number in the predefined list is equal to or greater than an expected maximum number of resources of the dynamic number of resources.

16. The apparatus of claim 11, further comprising:

a resource list stored on at least one of the one or more computer readable storage media, the resource list indicating a status of resources of the dynamic number of resources according to resource identifier; and

instructions stored on at least one of the one or more computer readable storage media that, when executed by the processing system, direct the processing system to;

maintain the resource list; and

determine a status of the associated resource identified by the resource identifier before communicating with the associated resource.

17. The apparatus of claim 11, further comprising:

instructions stored on at least one of the one or more computer readable storage media that, when executed by the processing system, direct the processing system to;

communicate with the associated resource identified by the resource identifier to determine its availability; and

in response to receiving a status of available, communicate the request to the associated resource;

in response to receiving a status of not available, calculate the modulus on the request identifier with at least a next number in the predefined list of numbers.

18. A resource locator comprising:

one or more computer readable storage media;

a predefined list of numbers stored on at least one of the one or more computer readable storage media, the predefined list of numbers comprising a plurality of prime numbers; and

program instructions stored on at least one of the one or more computer readable storage media that, when executed by a processing system, direct the processing system to;

map requests to associated resources of a dynamic number of resources, wherein for each request, the program instructions direct the processing system to;

obtain a numeric identifier (x) from the request;

retrieve at least a first number (n) in the predefined list of numbers;

calculate x mod n to generate a resource identifier;

determine whether the resource identifier identifies an available associated resource or an unavailable associated resource; and

in response to a determination that the resource identifier identifies the available associated resource, communicate the request to the available associated resource;

in response to a determination that the resource identifier identifies the unavailable associated resource, traverse the predefined list of numbers to retrieve a next number (m), calculate x mod m, and determine whether a resulting resource identifier identifies the available associated resource or the unavailable associated resource until the resource identifier identifies the available associated resource.

19. The resource locator of claim 18, wherein the numeric identifier is obtained by performing a hash function of a request key of the request.

20. The resource locator of claim 18, further comprising instructions stored on at least one of the one or more computer readable storage media that, when executed by the processing system, direct the processing system to:

in response to receiving a request that comprises an actual identifier of the associated resource, first use the actual identifier to communicate the request to the associated resource; and

if the associated resource is not available, then obtain the numeric identifier and calculate the x mod n to generate the resource identifier.