Systems and methods for GSLB site persistence

• US 8,260,926 B2
• Filed: 11/25/2008
• Issued: 09/04/2012
• Est. Priority Date: 11/25/2008
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Suganthi, Josephine, Raja, Murali, Kondamuru, Ravi, Narayana, Raghav Somanahalli
• Primary Examiner(s): Chan, Wing
• Assistant Examiner(s): Yohannes, Tesfay
• Application Number:
  US12/323,285
• Publication Number:
  US 20100131639A1
• Time in Patent Office: 1,379 Days
• Field of Search: 709/203, 709/206, 709/224, 709/228
• US Class Current: 709/226
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• 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 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/142 Managing session states for stateless protocols; Signalling session states; State transitions; Keeping-state mechanisms
• CPC Class Codes: H04L 67/2885 Hierarchically arranged intermediate devices, e.g. for hierarchical caching
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/563 Data redirection of data network streams

Abstract

The present invention provides systems and methods for maintaining site persistence in a hierarchical Global Server Load Balancing (GSLB) deployment. Via configuration of GSLB services locally and remotely on each of the GSLB appliances and LB appliances at a site, a site appliance identifies and associates requests from the GSLB with the site. Furthermore, the site appliance may receive a GSLB cookie with the client request and confirms the request is from the expected GSLB in the site hierarchy. When the load balancers receives a response from a server, the appliance may include the GSLB cookie with the response back to the client. The appliance may also include an LB cookie to identify the server selected by the LB. When the client sends another request, the request may include the GSLB and LB cookie. With this information, the GSLB and LB appliance may maintain site persistence for the client as well as server persistence at the site.

Claims

1. A method for maintaining site persistence via a load balancing virtual server in an hierarchical Global Server Load Balancing (GSLB) system, the method comprising:

a) receiving, by a load balancing virtual server at a first site, GSLB domain related information from a GSLB virtual server identifying whether site persistence for the GSLB virtual server is enabled, the GSLB virtual server load balancing a plurality of sites, each of the plurality of sites comprising one or more load balancing virtual servers load balancing a plurality of servers, the GSLB domain related information comprising a persistence identifier, a GSLB service internet protocol (IP) address and a GSLB service port;

b) storing, by the load balancing virtual server, the GSLB domain related information in association with a service of the load balancing virtual server identifying the GSLB virtual server;

c) receiving, by the load balancing virtual server, a request of a client forwarded by the GSLB virtual server, the request comprising a GSLB cookie, the GSLB cookie comprising the persistence identifier, the GSLB service IP address and port of the GSLB virtual server; and

d) determining, by the load balancing virtual server, from the GSLB cookie whether the request was forwarded from the GSLB virtual server associated with the service of the load balancing virtual server.

2. The method of claim 1, wherein step (a) further comprises identifying, by the GSLB virtual server, the load balancing virtual server as a remote service.

3. The method of claim 1, wherein step (b) further comprises identifying, by the load balancing virtual server responsive to receipt of the GSLB domain related information, that the load balancing virtual server is managed by the GSLB virtual server.

4. The method of claim 1, wherein step (d) further comprising determining, by the load balancing virtual server, that the request came from the GSLB virtual server.

5. The method of claim 4, further comprising receiving, by the load balancing virtual server, a response to the request from a server selected by the load balancing virtual server, and modifying the response to comprise the GSLB cookie.

6. The method of claim 1, further comprising receiving, by the load balancing virtual server, a response to the request from a server selected by the load balancing virtual server, and modifying the response to comprise the GSLB cookie and a load balancing cookie.

7. The method of claim 1, wherein step (d) further comprising determining, by the load balancing virtual server, that the request came for a remote GSLB service different than GSLB service representing the load balancing virtual server.

8. The method of claim 7, further comprising checking, by the load balancing virtual server, a status of the remote GSLB service.

9. The method of claim 8, further comprising redirecting, by the load balancing virtual server, the request of the client to the GSLB remote service if the status of the GSLB service indicates the GSLB service is available and site persistence is enabled.

10. The method of claim 7, further comprises proxying, by the load balancing virtual server, the request of the client to the remote GSLB service if the status of the remote GSLB service indicates it is available.

11. The method of claim 1, further comprising determining, by the load balancing virtual server the state of the GSLB virtual server.

12. The method of claim 11, further comprising redirecting, by the load balancing virtual server, the request of the client to a backup GSLB virtual server if the status of the GSLB virtual server is down or unavailable.

13. A system for maintaining site persistence via a load balancing virtual server in an hierarchical Global Server Load Balancing (GSLB) system, the system comprising:

a GSLB virtual server of a first appliance load balancing a plurality of sites, each of the plurality of sites comprising one or more load balancing virtual servers load balancing a plurality of servers;

a load balancing virtual server of a second appliance at a first site receiving GSLB domain related information from the GSLB virtual server identifying whether site persistence for the GSLB server is enabled and storing the GSLB domain related information in association with a service of the second appliance identifying the GSLB virtual server, the GSLB domain related information comprising a persistence identifier, a GSLB service internet protocol (IP) address and a GSLB service port;

wherein the load balancing virtual server receives a request of a client forwarded by the GSLB virtual server, the request comprising a GSLB cookie, the GSLB cookie comprising the persistence identifier, the GSLB service IP address and port of the GSLB virtual server; and

wherein the load balancing virtual server determines from the GSLB cookie whether the request was forwarded from the GSLB virtual server associated with the service of the load balancing virtual server.

14. The system of claim 13, wherein the GSLB virtual server identifies the load balancing virtual server as a remote service.

15. The system of claim 13, wherein the load balancing virtual server identifies responsive to receipt of the GSLB domain related information, that the load balancing virtual server is managed by the GSLB virtual server.

16. The system of claim 13, wherein the load balancing virtual server determines that the request came from the GSLB virtual server.

17. The system of claim 13, wherein the load balancing virtual server receives a response to the request from a server selected by the load balancing virtual server and modifies the response to comprise the GSLB cookie.

18. The system of claim 13, wherein the load balancing virtual server receives a response to the request from a server selected by the load balancing virtual server, and modifying the response to comprise the GSLB cookie and a load balancing cookie.

19. The system of claim 13, wherein the load balancing virtual server determines that the request came for a second GSLB service different than GSLB service representing the load balancing virtual server.

20. The system of claim 19, wherein the load balancing virtual server checks a status of the remote GSLB service.

21. The system of claim 20, wherein further the load balancing virtual server redirects the request of the client to the remote GSLB service if the status of the GSLB service indicates the GSLB service is available and site persistence is enabled.

22. The system of claim 19, wherein the load balancing virtual server proxies the request of the client to the remote GSLB service if the status of the remote GSLB service indicates it is not available.

23. The system of claim 13, wherein the load balancing virtual server determines the state of the GSLB virtual server.

24. The system of claim 23, wherein the load balancing virtual server redirects the request of the client to the backup GSLB virtual server if the status of the GSLB virtual server is down or unavailable.