Persistent group membership in a distributed computing system

• US 20050160143A1
• Filed: 12/19/2003
• Published: 07/21/2005
• Est. Priority Date: 12/19/2003
• Status: Active Grant

• Current Assignee: Meta Platforms, Inc. (f/k/a Facebook, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Zhang, Jifang, Bae, Myung M.
• Granted Patent: US 7,395,327 B2
• Time in Patent Office: Days
• US Class Current: 709/205
• CPC Class Codes: G06F 2209/505 Clust
• CPC Class Codes: G06F 9/5061 Partitioning or combining of resources

Abstract

A distributed system has a multiplicity of nodes. A group of the nodes subscribe to a group services process. The group is subject to dissolving. A list of persistent subscribers to the group is maintained. Subscriptions to members and states of the group that are persistent subscribers do not terminate in response to the group being dissolved. The persistent subscribers automatically receive a notice in response to the group being reestablished and do not need to re-subscribe to the group.

Claims

1. A method in a distributed computing system having a multiplicity of nodes capable of subscribing to at least one dissolvable group including a plurality of subscriber nodes comprising the step of:

maintaining a persistent subscriber node list of at least some of the plurality of subscriber nodes after the group dissolves.

2. The method according to claim 1 further comprising the steps of:

receiving a persistent subscription request from at least one of the plurality of subscriber nodes; and

adding the subscriber node to the persistent subscriber node list in response to the persistent subscription request.

3. The method according to claim 2 wherein the persistent subscriber node list excludes subscriber nodes of the plurality of subscriber nodes where a corresponding persistent subscriber request has not received.

4. The method according to claim 2 wherein said steps of maintaining, receiving and adding are performed in a first node of the multiplicity of nodes and the method further comprises the step of

communicating from one of the plurality of subscriber nodes to the first node the persistent request.

5. The method according to claim 1 further comprising the steps of:

determining a reestablishment of the at least one dissolved group; and

communicating a reestablishment notice indicative of the reestablishment to nodes of the persistent subscriber node list.

6. The method according to claim 5 wherein the reestablishment is not communicated to any of the plurality of subscriber nodes not included in the persistent node list.

7. The method according to claim 5 further comprising the steps of:

receiving a persistent subscriber request from at least one of the plurality of membership nodes; and

adding the node to the persistent subscriber node list in response to the persistent subscriber request.

8. The method according to claim 7 wherein the persistent subscriber node list excludes nodes of the plurality of membership nodes where a corresponding persistent subscriber request has not been received and further wherein the reestablishment is not communicated to any of the plurality of subscriber nodes not included in the persistent subscriber node list.

9. The method according to claim 7 wherein said aforementioned steps are performed in a first node of the plurality of subscriber nodes and the method further comprises the steps performed in a second of the plurality of subscriber nodes of:

communicating the persistent subscriber request to the first node;

exiting the dissolvable group in response to the group dissolving;

receiving the reestablishment notice; and

automatically rejoining the dissolved group in response thereto.

10. In a distributed computing system having a multiplicity of nodes capable of forming a dissolvable group including a plurality of subscriber nodes, a computer readable medium comprising programming instructions for

maintaining a persistent subscriber node list of at least some of the plurality of subscriber nodes of the dissolvable group after the group dissolves.

11. The computer readable medium according to claim 10 further comprising the instructions for:

receiving a persistent subscriber request from at least one of the plurality of subscriber nodes; and

adding the node to the persistent subscriber node list in response to the persistent subscriber request.

12. The computer readable media according to claim 11 wherein the persistent subscriber node list excludes nodes of the plurality of subscriber nodes where a corresponding persistent subscriber request has not been received.

13. The computer readable media according to claim 11 wherein the aforesaid instructions are performed in a first node of the plurality of subscriber nodes and the computer readable media further comprises instructions for

communicating the persistent subscriber request from another of the plurality of membership nodes to the first node.

14. The computer readable media according to claim 10 further comprising the instructions for:

determining a reestablishment of the at least one dissolved group; and

communicating a reestablishment notice indicative thereof to the nodes of the persistent subscriber node list.

15. The computer readable media according to claim 14 wherein the reestablishment is not communicated to any of the plurality of subscriber nodes not included in the persistent subscriber node list.

16. The computer readable media according to claim 14 further comprising the instructions for:

receiving a persistent subscriber request from at least one of the plurality of subscriber nodes; and

adding the node to the persistent subscriber node list in response to the persistent subscriber request.

17. The computer readable media according to claim 16 wherein the persistent subscriber node list excludes nodes of the plurality of subscriber nodes where a corresponding persistent subscriber request was not received and further wherein the reestablishment is not communicated to any of the plurality of subscriber nodes not included in the persistent subscriber node list.

18. The computer readable media according to claim 17 wherein said aforementioned instructions are performed in a first node of the multiplicity of nodes and the computer readable media further comprises the following instructions performed in one of the plurality of subscriber nodes for:

communicating the persistent request to the first node;

exiting the dissolvable group in response to the group dissolving;

receiving the reestablishment notice from the first node; and

automatically rejoining the dissolved group in response thereto.

19. In a distributed computing system having a multiplicity of nodes capable of forming a dissolvable group including a plurality of subscriber nodes, a computer readable medium comprising programming instructions for

communicating from one of the plurality of subscriber nodes a persistent subscriber request to be included on a persistent subscriber node list of at least some of the plurality of subscriber nodes of the dissolvable group after the group dissolves.

20. The computer readable media according to claim 19 further comprising instructions for:

exiting the dissolvable group in response to the group dissolving;

receiving a reestablishment notice indicative of a reestablishment of the group; and

automatically rejoining the group in response thereto.