SYSTEMS AND METHODS FOR STATEFUL SESSION FAILOVER BETWEEN MULTI-CORE APPLIANCES

• US 20100325485A1
• Filed: 06/22/2010
• Published: 12/23/2010
• Est. Priority Date: 06/22/2009
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Kamath, Sandeep, Verzunov, Sergey
• Granted Patent: US 8,335,943 B2
• Time in Patent Office: Days
• US Class Current: 714/15
• CPC Class Codes: G06F 11/2028 eliminating a faulty processor or activating a spare
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: G06F 2201/815 Virtual middleware or OS functionality using virtual machines to implement generic software techniques for error detection or fault masking G06F11/1484
• CPC Class Codes: H04L 41/06 Management of faults, events, alarms or notifications
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

The present disclosure presents systems and methods for maintaining operation of stateful sessions by a secondary multi-core appliance upon failover of a first multi-core appliance. A stateful session failover module of primary appliance may receive session states from each of the cores of the primary appliance. The stateful session failover module may communicate the session states of the cores of the primary appliance to a stateful session failover module of the secondary appliance. The stateful session failover module of the secondary appliance may update each of the cores of the secondary appliance with the session states. Upon failover, cores of the secondary appliance may maintain operation and features of the sessions handled by the primary appliance prior to failover using the received state sessions for each session maintained.

Claims

1. A method for maintaining session states across a plurality of multi-core devices intermediary to a plurality of a clients and one or more servers, the method comprising:

(a) obtaining, by a first failover module of a first multi-core device intermediary to a plurality of a clients and one or more servers, from each core of the first multi-core device, a state of each session between a client and a server maintained by that core;

(b) receiving, by a second failover module of a second multi-core device intermediary to the plurality of clients and the one or more servers, from the first failover module the state of each session for each of the cores of the first-multi-core device; and

(c) assigning, by the second failover module, to each core of the second multi-core device, one or more sessions and corresponding session states.

2. The method of claim 1, wherein step (a) further comprises communicating, by each core, the state of each session managed by that core to the first failover module responsive to an expiration of a timer.

3. The method of claim 1, wherein step (a) further comprises communicating, by each core, the state of a session managed by that core to the first failover module responsive to a change to the state of the session.

4. The method of claim 1, wherein step (a) further comprises operating, by the first multi-core device, the failover module on a designated core.

5. The method of claim 1, wherein step (a) further comprises sending, by each of the cores to the first failover module, a message identifying a location in shared memory storing a session state.

6. The method of claim 1, wherein step (b) further comprises establishing, by a first core of the second multi-core device, a failover connection with a second core of the first multi-core device.

7. The method of claim 1, further comprising communicating, by the first failover module to the second failover module, updated states of each session.

9. The method of claim 1, further comprising detecting, by a failover detector, that the first multi-core device is not available.

10. The method of claim 9, further comprising using, by the second multi-core device responsive to the detection, the state of each of the sessions to maintain operation of each of the sessions.

12. The method of claim 1, wherein step (a) further comprises communicating, by each core, the state of each session managed by that core to the first failover module responsive to an expiration of a timer.

13. The method of claim 1, wherein step (a) further comprises communicating, by each core, the state of a session managed by that core to the first failover module responsive to a change to the state of the session.

14. The method of claim 1, wherein step (a) further comprises operating, by the first multi-core device, the failover module on a designated core.

15. The method of claim 1, wherein step (a) further comprises sending, by each of the cores to the first failover module, a message identifying a location in shared memory storing a session state.

8. The method of claim 8, further comprising propagating the updates states of each session to the core for which the session was assigned by the second failover module.

11. A method for maintaining session states across a plurality of multi-core devices intermediary to a plurality of a clients and one or more servers, the method comprising:

(a) receiving, by a second failover module of a second multi-core device intermediary to a plurality of clients and one or more servers, from a first failover module of a first multi-core device, a state of each session between the plurality of clients and the one or more servers maintained by a plurality of cores of the first multi-core device;

(b) assigning, by the second failover module, one or more sessions and corresponding session states maintained by the first multi-core device to each core of the second multi-core device;

(c) detecting, by a failover detector of the second multi-core device, that the first multi-core device is unavailable; and

(d) establishing, by the second multi-core device, a packet processing engine on each core to maintain operation of each session assigned to the corresponding core in accordance with the corresponding session state.

16. The method of claim 11, wherein step (c) further comprises detecting that at least one core of the first multi-core device is not available.

17. The method of claim 11, wherein step (c) further comprises determining, by the second multi-core device responsive to detection, to failover each of the sessions from the first multi-code device to the second multi-core device.

18. The method of claim 11, wherein step (c) further comprises monitoring, by a failover detector of the second multi-core device, a status of operation of one or more cores of the first multi-core device.

19. The method of claim 11, wherein step (d) further comprises receiving, by the second multi-core device, configuration information for a packet processing engine of the first multi-core device.

20. The method of claim 18, further comprising configuring, by the second multi-core device, the packet processing on each core based on the received configuration information.