DEVICE, SYSTEM, AND METHOD FOR CLIENT-GOVERNED SESSION PERSISTENCY BETWEEN ONE OR MORE CLIENTS AND SERVERS OF A DATA CENTER

• US 20140006578A1
• Filed: 06/29/2012
• Published: 01/02/2014
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Kohn, Rodolfo, Ghamrawi, Munir, Mahankali, Sridhar
• Granted Patent: US 9,325,785 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G06F 2221/2141 Access rights, e.g. capability lists, access control lists, access tables, access matrices
• CPC Class Codes: H04L 67/1027 Persistence of sessions during load balancing
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• 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

A device, system, and method for maintaining session persistency between one or more clients and one or more data servers includes providing a persistent session between the client(s) and data server(s) as a function of a load balancer hint header included in a message received by the load balancer from the client(s). The client(s) modifies the message, which may be generated by an application, to include the load balancer hint header that identifies a location, within the message, of a session ID that identifies the particular persistent session. The load balancer identifies the data server(s) from a session-server table based on the session ID and transmits the message to the identified data server(s). The load balancer may communicate with other load balancers, if the load balancer is unable to locate the corresponding data server, to determine the location of the corresponding data server(s).

Claims

1. A load balancer to balance workload from a plurality of client computing devices across a plurality of data servers, the load balancer comprising:

a communication module to receive a message from a client computing device of the plurality of client computing devices; and

a session persistency module to provide a persistent session between one or more client computing devices and one or more data servers as a function of a load balancer hint header included in the message, wherein the load balancer hint header identifies a location, within the message, of a session identifier that identifies the persistent session.

2. The load balancer of claim 1, wherein the session persistency module to:

retrieve the session identifier as a function of the load balancer hint header;

compare the session identifier to a session-server table to identify at least one data server to receive the message; and

transmit the message to the identified at least one data server.

3. The load balancer of claim 1, wherein the load balancer hint header comprises a location identifier that identifies the location, within the message, of the session identifier.

4. The load balancer of claim 3, wherein the location identifier comprises an offset value that identifies the location, within the message, of the session identifier relative to one of (i) a location of the load balancer hint header in the message or (ii) the beginning of the message.

5. The load balancer of claim 3, wherein the load balancer hint header further comprises a length identifier that identifies a length of the session identifier.

6. The load balancer of claim 1, wherein the load balancer hint header comprises a location identifier that identifies the location within the message of the session identifier and an action type that indicates an action to be performed by the load balancer, and

wherein the session persistency module to perform one of a plurality of actions based on the action type included in the load balancer hint header.

7. The load balancer of claim 6, wherein the session persistency module, in response to the load balancer hint header including a corresponding action type, to:

determine whether the session identifier is included in a local session-server table, and

transmit, in response to determining that the session identifier is not included in the local session-server table, a request to at least one other load balancer to determine whether the session identifier is included in a session-server table managed by the other load balancer.

8. The load balancer of claim 7, wherein the session persistency module to:

receive an acknowledgment from another load balancer that the session identifier is included in a session-server table managed by the other load balancer, and

transmit, in response to the acknowledgement, a redirect message to the client computing device that sent the message, wherein the redirect message includes load balancer identification data that identifies the load balancer that manages the session-server table in which the session identifier is included.

9. The load balancer of claim 7, wherein the session persistency module to:

receive a response message from the corresponding data server identified in the session-server table managed by the other load balancer to be associated with the session identifier; and

retransmit the response message to the client computing device that sent the message.

10. The load balancer of claim 1, wherein the load balancer hint header comprises a label that identifies the load balancer hint header, a location identifier that identifies the location within the message of the session identifier, a length identifier that identifies the length of the session identifier, and an action type that indicates an action to be performed by the load balancer.

11. A client computing device to communicate with one or more data servers of a data center, the client computing device comprising:

a session persistency module to modify a message to be sent from an application executing on the client computing device to the one or more data servers to include a load balancer hint header that identifies a location, within the message, of a session identifier that identifies a persistent session between the client computing device and the one or more data servers; and

a communication module to transmit the modified message to a load balancer that manages the one or more data servers.

12. The client computing device of claim 11, wherein the load balancer hint header comprises a location identifier that identifies the location, within the message, of the session identifier.

13. The client computing device of claim 12, wherein the load balancer hint header further comprises a length identifier that identifies a length of the session identifier.

14. The client computing device of claim 13, wherein the load balancer hint header further comprises an action type that indicates an action to be performed by the load balancer.

15. The client computing device of claim 14, wherein the session persistency module to:

determine the action to be performed by the load balancer; and

set the action type to indicate the action to be performed by the load balancer.

16. The client computing device of claim 14, wherein the action type indicates that the load balancer is to communicate with another load balancer to locate a corresponding data server with which the client computing device has a current persistent session.

17. A method to provide a persistent session between a client computing device and a plurality of data servers, the method comprising:

receiving, with a load balancer, a message from the client computing device;

determining, with the load balancer, a location of a session identifier within the message based on a load balancer hint header included in the message, the session identifier identifying the persistent session;

comparing, with the load balancer, the session identifier to a session-server table managed by the load balancer to identify at least one data server of the plurality of data servers to receive the message; and

transmitting the message from the load balancer to the identified at least one data server.

18. The method of claim 17, wherein determining the location of the session identifier comprises determining the location of the session identifier as a function of (i) a location identifier of the load balancer hint header that identifies the location, within the message, of the session identifier and (ii) a length identifier that identifies a length of the session identifier.

19. The method of claim 18, wherein determining the location of the session identifier as a function of the location identifier comprises determining the location of the session identifier, within the message, as a function of the location identifier and the location of the load balancer hint header within the message.

20. The method of claim 17, further comprising determining an action to be performed by the load balancer based on an action type included in the load balancer header, wherein the action type indicates the action to be performed by the load balancer.

21. The method of claim 20, further comprising, in response to determining a corresponding action based on the action type, (i) determining whether the session identifier is included in a local session-server table and (ii) transmitting, in response to determining that the session identifier is not included in the local session-server table, a request to at least one other load balancer to determine whether the session identifier is included in a session-server table managed by the other load balancer.

22. The method of claim 21, further comprising:

receiving an acknowledgment, in response to the request, from another load balancer that the session identifier is included in a session-server table managed by the other load balancer, and

transmitting, in response to the acknowledgement, a redirect message to the client computing device that sent the message, wherein the redirect message includes load balancer identification data that identifies the load balancer that manages the session-server table in which the session identifier is included.

23. The method of claim 21, further comprising:

receiving a response message, in response to the request, from the corresponding data server identified in the session-server table managed by the other load balancer to be associated with the session identifier; and

retransmitting the response message to the client computing device that sent the message.

24. A method for persistent session communication between a client computing device and a data server of a plurality of data servers, the method comprising:

modifying a message to be sent from an application executing on the client computing device to the data server to include a load balancer hint header that identifies a location, within the message, of a session identifier that identifies the persistent session; and

transmitting the modified message to a load balancer that manages the data server.

25. The method of claim 24, wherein modifying the message comprises setting a location identifier of the load balancer hint header to identify the location, within the message, of the session identifier.

26. The method of claim 24, wherein modifying the message comprises setting a location identifier of the load balancer hint header to identify an the location, within the message, of the session identifier relative to one of (i) a location of the load balancer hint header in the message or (ii) the beginning of the message.

27. The method of claim 25, wherein modifying the message comprises setting a length identifier of the load balancer hint header that identifies a length of the session identifier.

28. The method of claim 27, wherein modifying the message comprises setting an action type of the load balancer hint header that indicates an action to be performed by the load balancer.

29. The method of claim 28, wherein setting the action type comprises setting the action type to indicate that the load balancer is to create a persistent session between the client computing device and the data server.

30. The method of claim 28, wherein setting the action type comprises setting the action type to indicate that the load balancer is to communicate with another load balancer to locate a corresponding data server with which the client computing device has a current persistent session.