Session Affinity Cache and Manager

• US 20090177778A1
• Filed: 01/04/2008
• Published: 07/09/2009
• Est. Priority Date: 01/04/2008
• Status: Active Grant

• Current Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Original Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Inventors: Turk, Mladen
• Granted Patent: US 8,583,810 B2
• Time in Patent Office: Days
• US Class Current: 709/227
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1006 with static server selection, e.g. the same server being selected for a specific client
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

A method and apparatus for managing sessions by a load balancer using a session affinity cache to manage common session identifiers and resource node session identifiers. A session affinity manager within the load balancer utilizes a common session identifier to represent multiple sessions to a client. The session affinity manager provided generates a common session identifier for a set of resource node sessions for each client. The relationship between the resource node session identifiers and common session identifier is maintained in the session affinity cache by the session affinity manager. The session affinity manager translates client requests using the common session identifier into requests using the resource node session identifier retrieved from the session affinity cache. The session affinity manager rewrites resource node responses to use a common session identifier in place of resource node session identifiers.

Claims

1. A computer-implemented method comprising:

receiving a request for a resource, the request including a common session identifier and a resource identifier;

determining a resource node session identifier based on the common session identifier and the resource identifier; and

forwarding the request to the resource node using the resource node session identifier.

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

generating a new common session identifier between a client sending the request and the resource node, if the common session identifier is not found in a session affinity cache.

3. The computer-implemented method of claim 1, further comprising:

adding a common session identifier entry to a session affinity cache, if the common session identifier is not found in the session affinity cache.

4. The computer-implemented method of claim 1, further comprising:

forwarding the request to a load balancer to select a resource node to service the request, if the common session identifier and resource identifier are not found in the session affinity cache.

5. The computer-implemented method of claim 4, further comprising:

updating the session affinity cache to add the resource node session identifier to a common session identifier entry for the request in the session affinity cache upon receipt from a load balancer or resource node.

6. The computer-implemented method of claim 5, wherein the common session identifier relates a single name and value pair to a plurality of resource nodes and resource identifiers.

7. The computer-implemented method of claim 1, further comprising:

rewriting the resource node session identifier to the common session identifier in a response from the resource node to the client.

8. The computer-implemented method of claim 6, wherein each of the plurality of resource nodes is from a separate vendor.

9. A computer readable medium, having instructions stored therein, which when executed, cause a computer to perform a set of operations comprising:

receiving a request for a resource, the request including a common session identifier and a resource identifier;

determining a resource node session identifier based on the common session identifier and the resource identifier; and

forwarding the request to the resource node using the resource node session identifier.

10. The computer readable medium of claim 9, wherein searching the content history cache comprises:

generating a new common session identifier between a client sending the request and the resource node, if the common session identifier is not found in a session affinity cache.

11. The computer readable medium of claim 9, wherein searching the content history cache comprise:

adding a common session identifier entry to a session affinity cache, if the common session identifier is not found in the session affinity cache.

12. The computer readable medium of claim 9, wherein selecting the resource node comprises:

forwarding the request to a load balancer to select a resource node to service the request, if the common session identifier and resource identifier are not found in the session affinity cache.

13. The computer readable medium of claim 12, having further instructions therein, which when executed, cause the computer to perform a further set of operations, further comprising:

updating the session affinity cache to add the resource node session identifier to a common session identifier entry for the request in the session affinity cache upon receipt from a load balancer or resource node.

14. The computer readable medium of claim 13, wherein the common session identifier relates a single name and value pair to a plurality of resource nodes and resource identifiers.

15. The computer readable medium of claim 9, having further instructions stored therein, which when executed perform a set of operations, further comprising:

rewriting the resource node session identifier to the common session identifier in a response from the resource node to the client.

16. The machine readable medium of claim 9, wherein each of the plurality of resource nodes is from a separate vendor.

17. A system comprising:

a session affinity manager, the session affinity manager to track a relationship between a common session identifier and a plurality of resource node session identifiers; and

session affinity cache coupled to the session affinity manager, the session affinity cache to store the relationship data.

18. The system of claim 17, further comprising:

a load balancer coupled to the session affinity manager and to one of a plurality of resource nodes, the load balancer to service a request from a client.

19. The system of claim 17, wherein the session affinity manager includes a session generator to establish a session for a request.

20. The system of claim 17, wherein the session affinity manager modifies a request by translating a common session identifier to a resource node session identifier in the request.