Cluster system, load balancer, node reassigning method and recording medium storing node reassigning program

• US 20070121490A1
• Filed: 03/29/2006
• Published: 05/31/2007
• Est. Priority Date: 11/30/2005
• Status: Abandoned Application

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Okuyama, Satoshi, Iwakawa, Akinori
• Application Number:
  US11/391,368
• Publication Number:
  US 20070121490A1
• Time in Patent Office: Days
• US Class Current: 370/218
• 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 67/1034 Reaction to server failures by a load balancer

Abstract

Each of node servers provided in a cluster system connected to load balancers includes a storage portion for storing node-session information that associates a session ID and a node server in charge with each other and node life/death information, a node checking portion for, when receiving a message sent from any one of the load balancers, judging whether or not a node server in charge of the session of the message is functioning normally, and a node reassigning portion for updating the node-session information so that the node server in charge of the session is changed to an alternative node server and sending data indicating the alternative node server to a load balancer different from the load balancer that has sent the message. This allows the cluster system to process messages from a plurality of load balancers efficiently even when the node server is not functioning normally.

Claims

1. A cluster system comprising:

a plurality of node servers that are connected to a plurality of load balancers and process messages from a plurality of user terminals respectively accessing the plurality of load balancers so as to allow a data communication between the plurality of user terminals;

wherein each of the plurality of node servers is accessible to a storage portion storing node-session information that associates a session ID for identifying a session, which is a series of data communications conducted by a same user terminal, and a node server in charge for processing a message belonging to the session identified by the session ID with each other, and node life/death information that indicates whether or not each of the plurality of node servers is functioning normally, and

each of the plurality of node servers comprises

a node checking portion for, when receiving a message containing the session ID from any one of the plurality of load balancers, judging whether or not the node server in charge of the session identified by the session ID contained in the message is functioning normally using the node-session information and the node life/death information, and

a node reassigning portion for, if the node checking portion judges that the node server in charge of the session is not functioning normally, updating the node-session information so that the node server in charge of the session is changed to an alternative node server and sending data indicating the session and data indicating the alternative node server to the plurality of load balancers.

2. The cluster system according to claim 1, wherein, after an access regarding the session is made to the node server from a load balancer different from the load balancer that has sent the message, the node reassigning portion sends the session ID identifying the session and the data indicating the alternative node server to the load balancer that has made the access.

5. A load balancer, which is the load balancer connected to the cluster system according to claim 1, comprising:

a storage portion for storing node-session information that associates a session ID and a node server in charge for conducting a processing regarding a session identified by the session ID with each other;

a load distributing portion for receiving a message from the plurality of user terminals, acquiring the session ID from the message and assigning the message to a node server determined based on the session ID and the node-session information; and

an updating portion for, when the data indicating the session and the data indicating the alternative node server are sent from the node reassigning portion provided in the node server, updating the node-session information stored in the storage portion based on both the data that are sent.

3. A cluster system comprising:

a plurality of node servers that are connected to a plurality of load balancers conducting data communications according to different communication protocols and process messages from a plurality of user terminals having different communication protocols respectively accessing the plurality of load balancers so as to allow the data communications between the plurality of user terminals having different communication protocols;

wherein each of the plurality of node servers is accessible to a storage portion storing node-session information that associates a session ID for identifying a session, which is a series of data communications conducted between user terminals having different communication protocols, and a node server in charge for conducting a processing regarding the session identified by the session ID with each other, and node life/death information that indicates whether or not each of the plurality of node servers is functioning normally, and

each of the plurality of node servers comprises

a node checking portion for, when receiving a message sent from any one of the plurality of load balancers, judging whether or not the node server in charge of the session to which the message belongs is functioning normally using the node-session information and the node life/death information, and

a node reassigning portion for, if the node checking portion judges that the node server in charge of the session is not functioning normally, updating the node-session information so that the node server in charge of the session is changed to an alternative node server and sending data indicating the session and data indicating the alternative node server to another load balancer having a different communication protocol from the load balancer that has sent the message.

4. The cluster system according to claim 3, wherein the plurality of load balancers comprise a load balancer for conducting a data communication according to an HTTP protocol and a load balancer for conducting a data communication according to an SIP protocol.

6. A node reassigning method conducted by a plurality of node servers that are connected to a plurality of load balancers and process messages from a plurality of user terminals respectively accessing the plurality of load balancers so as to allow a data communication between the plurality of user terminals in a cluster system comprising the plurality of node servers, the method comprising:

an operation in which each of the plurality of node servers stores node-session information that associates a session ID for identifying a session, which is a series of data communications conducted by a same user terminal, and a node server in charge for conducting a processing regarding the session identified by the session ID with each other, and node life/death information that indicates whether or not each of the plurality of node servers is functioning normally;

a node checking operation in which, when receiving a message sent from any one of the plurality of load balancers, any one of the plurality of node servers judges whether or not the node server in charge of the session to which the message belongs is functioning normally using the node-session information and the node life/death information; and

a node reassigning operation in which, if the node server in charge of the session is judged not to be functioning normally in the node checking operation, the node server updates the node-session information so that the node server in charge of the session is changed to an alternative node server and sends data indicating the session and data indicating the alternative node server to the plurality of load balancers.

7. A recording medium storing a node reassigning program causing a plurality of node servers that are connected to a plurality of load balancers and process messages from a plurality of user terminals respectively accessing the plurality of load balancers so as to allow a data communication between the plurality of user terminals in a cluster system comprising the plurality of node servers to execute

a process of storing in a storage portion of the node server node-session information that associates a session ID for identifying a session, which is a series of data communications conducted by a same user terminal, and a node server in charge for conducting a processing regarding the session identified by the session ID with each other, and node life/death information that indicates whether or not each of the plurality of node servers is functioning normally;

a node checking process of, when receiving a message sent from any one of the plurality of load balancers, judging whether or not the node server in charge of the session to which the message belongs is functioning normally using the node-session information and the node life/death information; and

a node reassigning process of, if the node server in charge of the session is judged not to be functioning normally in the node checking process, updating the node-session information so that the node server in charge of the session is changed to an alternative node server and sending information indicating the session and data indicating the alternative node server to the plurality of load balancers.