System and method for implementing a clustered load balancer

• US 7,272,653 B2
• Filed: 09/26/2001
• Issued: 09/18/2007
• Est. Priority Date: 09/28/2000
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Thubert, Pascal, Levy-Abegnoli, Eric
• Primary Examiner(s): Caldwell; Andrew
• Assistant Examiner(s): LIN, KELVIN Y
• Application Number:
  US09/963,737
• Publication Number:
  US 20020040402A1
• Time in Patent Office: 2,183 Days
• Field of Search: 709/207, 709/232, 709/224, 709/226, 709/229, 709/238, 342/359, 370/316, 711/152
• US Class Current: 709/229
• CPC Class Codes: H04L 61/35 involving non-standard use of addresses for implementing network functionalities, e.g. coding subscription information within the address or functional addressing, i.e. assigning an address to a function
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/1019 Random or heuristic server selection
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs

Abstract

A system and method of organizing a front-end load balancing function for implementing an Internet site so the transmission control protocol (TCP) connections, established between the front-end load balancing function and end-users, are spread over more than one individual load balancer (ILB). Each ILB consistently self-asserts a primary ILB owner for each one of the TCP connections. Hence, each ILB, for each delegated TCP connection can process each TCP connection on behalf of the load balancing function while handing off the other TCP connections to the corresponding ILB owners. Also, each ILB consistently self-asserts a backup ILB owner for each one of the TCP connections so the designated back up ILB owner takes over the processing of an ILB owned TCP connection should the ILB owner become incapable of processing the delegated TCP connection.

Claims

1. A method of load balancing connections between a plurality of servers and a plurality of clients, wherein a plurality of load balancers couple said plurality of servers and said plurality of clients, said method comprising:

in response to a receiving load balancer out of said plurality of load balancers receiving a communication from at least one of said plurality of clients, determining a primary load balancer and a backup load balancer for handling said communication;

storing an identity of said primary load balancer and said backup load balancer corresponding to said communication in each of said plurality of load balancers;

forwarding said communication to said primary load balancer for transmission to at least one of said plurality of servers; and

in response to determining said primary load balancer is not available, forwarding said communication to said determined backup load balancer for transmission to at least one of said plurality of servers.

2. The method of claim 1, wherein said determining further includes:

calculating a plurality of scores, wherein each of said plurality of scores corresponds to a respective one of said plurality of load balancers;

ranking said plurality of scores from a highest score to a lowest score;

designating as said primary load balancer one of said plurality of load balancers corresponding to said highest score; and

designating as said backup load balancer one of said plurality of load balancers corresponding to a second highest score.

3. The method of claim 1, further comprising:

in response to determining said receiving load balancer is said primary load balancer, transmitting said communication to at least one of said plurality of servers.

4. A system for load balancing connections between a plurality of servers and a plurality of clients, said system comprising:

a plurality of load balancers, including

a receiving load balancer, further including;

means for receiving a communication from at least one of said plurality of clients;

means for determining said primary load balancer and said backup load balancer for handling said communication;

means for storing an identity of said primary load balancer and said backup load balancer corresponding to said communication in each of said plurality of load balancers;

means for forwarding said communication to said primary load balancer for transmission to at least one of said plurality of servers; and

means for forwarding said communication to said determined backup load balancer for transmission to at least one of said plurality of servers, in response to determining said primary load balancer is not available.

5. The system of claim 4, wherein said receiving load balancer further includes:

means for determining said primary load balancer and said backup load balancer for handling said communication by calculating a plurality of scores, wherein each of said plurality of scores corresponds to a respective one of said plurality of load balancers;

means for ranking said plurality of scores from a highest score to a lowest score;

means for designating as said primary load balancer one of said plurality of load balancers corresponding to said highest score; and

means for designating as said backup load balancer one of said plurality of load balancers corresponding to a second highest score.

6. The system of claim 4, wherein said receiving load balancer further includes:

means for transmitting said communication to at least one of said plurality of servers, in response to determining said receiving load balancer is said primary load balancer.

7. A load balancer out of a plurality of load balancers for load balancing connections between a plurality of servers and a plurality of clients, said load balancer comprising:

means for receiving a communication from at least one of said plurality of clients;

means for determining a primary load balancer and a backup load balancer for handing said communication;

means for storing an identity of said primary load balancer and said backup load balancer corresponding to said communication in each of said plurality of load balancers;

means for forwarding said communication to said primary load balancer for transmission to at least one of said plurality of servers; and

means for forwarding said communication to said determined backup load balancer for transmission to at least one of said plurality of servers, in response to determining said primary load balancer is not available.

8. The load balancer of claim 7, further comprising:

means for calculating a plurality of scores, wherein each of said plurality of scores corresponds to a respective one of said plurality of load balancers;

means for ranking said plurality of scores from a highest score to a lowest score;

means for designating as said primary load balancer one of said plurality of load balancers corresponding to said highest score; and

means for designating as said backup load balancer one of said plurality of load balancers corresponding to a second highest score.

9. The load balancer of claim 7, further comprising:

means for transmitting said communication to at least one of said plurality of servers, in response to determining said load balancer is said primary load balancer.

10. A computer program product for load balancing connections between a plurality of servers and a plurality of clients, wherein a plurality of load balancers couple said plurality of servers and said plurality of clients, said computer program product comprising:

instructions, stored on computer-readable media, for determining a primary load balancer and a backup load balancer for handling said communication, in response to a receiving load balancer out of said plurality of load balancers receiving a communication from at least one of said plurality of clients;

instructions, stored on computer-readable media, for storing an identity of said primary load balancer and said backup load balancer corresponding to said communication in each of said plurality of load balancers;

instructions, stored on computer-readable media, for forwarding said communication to said primary load balancer for transmission to at least one of said plurality of servers; and

instructions, stored on computer-readable media, for forwarding said communication to said determined backup load balancer for transmission to at least one of said plurality of servers, in response to determining said primary load balancer is not available.

11. The computer program product of claim 10, further comprising:

instructions, stored on computer-readable media, for calculating a plurality of scores, wherein each of said plurality of scores corresponds to a respective one of said plurality of load balancers;

instructions, stored on computer-readable media, for ranking said plurality of scores from a highest score to a lowest score;

instructions, stored on computer-readable media, for designating as said primary load balancer one of said plurality of load balancers corresponding to said highest score; and

instructions, stored on computer-readable media, for designating as said backup load balancer one of said plurality of load balancers corresponding to a second highest score.

12. The computer program product of claim 10, further comprising:

instructions, stored on computer-readable media, for transmitting said communication to at least one of said plurality of servers, in response to determining said receiving load balancer is said primary load balancer.