Method and system for providing highly available services based on a load balancing policy and a reusable connection context object

• US 7,058,717 B2
• Filed: 07/25/2002
• Issued: 06/06/2006
• Est. Priority Date: 07/25/2002
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Chao, Ching-Yun, Liang, Chunlong
• Primary Examiner(s): Prieto, Beatriz
• Application Number:
  US10/205,540
• Publication Number:
  US 20040019680A1
• Time in Patent Office: 1,412 Days
• Field of Search: 709/226, 718/105
• US Class Current: 709/226
• CPC Class Codes: H04L 41/0893 Assignment of logical groups to network elements
• CPC Class Codes: H04L 41/0894 Policy-based network configuration management
• CPC Class Codes: H04L 41/0896 Bandwidth or capacity management, i.e. automatically increasing or decreasing capacities flow or congestion control using dynamic resource allocation, e.g. in-call renegotiation, H04L47/76
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• 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 67/1017 based on a round robin mechanism
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• CPC Class Codes: H04L 67/306 User profiles
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• 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
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

An example of a solution provided here comprises: providing a connection pool, said connection pool including a connection for each of a plurality of servers; applying a load-balancing policy to said connection pool; and assigning a connection from said connection pool to a client, according to said load-balancing policy. Another example of a solution comprises: providing a plurality of directory servers; providing a connection pool, said connection pool including a connection for each of said plurality of directory servers; applying a load-balancing policy to said connection pool; and assigning a connection from said connection pool to a client, according to said load-balancing policy. Methods for providing highly available services, systems for executing such methods, and instructions on a computer-usable medium, for executing such methods, are provided.

Claims

1. A method for providing highly available services, said method comprising:

providing a connection pool, said connection pool including a connection for each of a plurality of servers, wherein the connection pool comprises a pool of reusable connection context objects, each reusable connection context object containing information about an associated server in the plurality of servers;

applying a load-balancing policy to said connection pool;

assigning a reusable connection context object from said connection pool to a client, according to said load-balancing policy, in response to a request from the client; and

managing a content of the connection pool, wherein managing the content of the connection pool comprises periodically waking a connection pool management thread that, for each connection in the connection pool;

determines if the connection in the connection pool was accessed during a previous sleep period of the connection pool management thread;

checks availability of a server associated with the connection if the connection was not accessed during a previous sleep period of the connection pool management thread;

maintains a reusable connection context object associated with the connection in the connection pool if the connection was accessed during the previous sleep period of the connection pool management thread or the check of the availability of the server results in an indication that the server is available; and

removes the reusable connection context object associated with the connection from the connection pool if the check of the availability results in an indication that the server is not available.

2. The method of claim 1, wherein the connection pool management thread further:

attempts to connect to at least one server of said plurality of servers that has a status indicating it was previously unavailable;

determining if a connection to the at least one server of said plurality of servers that has a status indicating it was previously unavailable is successfully made; and

adding a reusable connection context object to the connection pool for the at least one sewer if the connection is successfully made.

3. The method of claim 1, further comprising:

detecting a failed operation;

changing a status of a server that corresponds to the assigned reusable connection context object; and

assigning another reusable connection context object from said connection pool to said client.

4. The method of claim 1, wherein said applying a load-balancing policy further comprises:

allowing a “

read”

operation on any of said plurality of servers; and

allowing a “

write”

operation on at least one of said plurality of servers, that is designated for “

read” and

“

write”

operations.

5. The method of claim 1, further comprising:

determining if at least one server in the plurality of servers is currently available to handle a request from the client; and

creating one or more reusable connection context objects in the connection pool for operational servers in the plurality of servers if no server is currently available to handle the request from the client.

6. The method of claim 1, wherein providing a connection pool further comprises:

providing a connection pool hashtable, wherein a key for the connection pool hashtable is a uniform resource locator of the servers in the plurality of servers and a value for the connection pool hashtable is a context for the servers in the plurality of servers.

7. A method for providing highly available services, said method comprising:

providing a plurality of directory servers;

providing a connection pool, said connection pool including a connection for each of said plurality of directory servers, wherein the connection pool comprises a pool of reusable connection context objects, each reusable connection context object containing information about an associated directory server in the plurality of directory servers;

applying a load-balancing policy to said connection pool;

assigning a reusable connection context object from said connection pool to a client, according to said load-balancing policy, in response to a request from the client; and

managing a content of the connection pool, wherein managing the content of the connection pool comprises periodically waking a connection pool management thread that, for each connection in the connection pool;

determines if the connection in the connection pool was accessed during a previous sleep period of the connection pool management thread;

checks availability of a server associated with the connection if the connection was not accessed during a previous sleep period of the connection pool management thread;

maintains a reusable connection context object associated with the connection in the connection pool if the connection was accessed during the previous sleep period of the connection pool management thread or the check of the availability of the server results in an indication that the server is available; and

removes the reusable connection context object associated with the connection from the connection pool if the check of the availability results in an indication that the server is not available.

8. The method of claim 7, wherein the connection pool management thread further:

attempts to connect to at least one server of said plurality of servers that has a status indicating it was previously unavailable;

determining if a connection to the at least one server of said plurality of servers that has a status indicating it was previously unavailable is successfully made; and

adding a reusable connection context object to the connection pool for the at least one server if the connection is successfully made.

9. The method of claim 7, further comprising:

detecting a failed operation;

changing a status of a server that corresponds to the assigned reusable connection context object; and

assigning another reusable connection context object from said connection pool to said client.

10. The method of claim 7, wherein context information in the reusable connection context objects is JNDI context information.

11. The method of claim 7, wherein said plurality of directory servers includes a plurality of directory servers utilizing LDAP.

12. The method of claim 7, wherein:

said plurality of directory servers includes;

at least one directory server for “

read” and

“

write”

operations; and

at least one directory server for “

read”

operations; and

said applying a load-balancing policy further comprises;

allowing a “

write”

operation on said at least one directory server for “

read” and

“

write”

operations; and

allowing a “

read”

operation on any of said plurality of directory servers.

13. The method of claim 7, further comprising:

determining if at least one server in the plurality of servers is currently available to handle a request from the client; and

creating one or more reusable connection context objects in the connection pool for operational servers in the plurality of servers if no server is currently available to handle the request from the client.

14. The method of claim 7, wherein providing a connection pool further comprises:

providing a connection pool hashtable, wherein a key for the connection pool hashtable is a uniform resource locator of the servers in the plurality of servers and a value for the connection pool hashtable is a context for the servers in the plurality of servers.

15. A system for providing highly available services, said system comprising:

means for providing a connection pool, said connection pool including a connection for each of a plurality of servers, wherein the connection pool comprises a pool of reusable connection context objects, each reusable connection context object containing information about an associated directory server in the plurality of directory servers;

means for applying a load-balancing policy to said connection pool;

means for assigning a reusable connection context object from said connection pool to a client, according to said load-balancing policy, in response to a request from the client; and

means for managing a content of the connection pool, wherein the means for managing the content of the connection pool comprises means for periodically waking a connection pool management thread that, for each connection in the connection pool;

determines if the connection in the connection pool was accessed during a previous sleep period of the connection pool management thread;

checks availability of a server associated with the connection if the connection was not accessed during a previous sleep period of the connection pool management thread;

maintains a reusable connection context object associated with the connection in the connection pool if the connection was accessed during the previous sleep period of the connection pool management thread or the check of the availability of the server results in an indication that the server is available; and

removes the reusable connection context object associated with the connection from the connection pool if the check of the availability results in an indication that the server is not available.

16. The system of claim 15, wherein the connection pool management thread further;

attempts to connect to at least one server of said plurality of servers that has a status indicating it was previously down unavailable;

determining if a connection to the at least one server of said plurality of servers that has a status indicating it was previously unavailable is successfully made; and

adding a reusable connection context object to the connection pool for the at least one server if the connection is successfully made.

17. The system of claim 15, further comprising:

means for detecting a failed operation;

means for changing a status of a server that corresponds to the assigned reusable connection context object; and

means for assigning another reusable connection context object from said connection pool to said client.

18. The system of claim 15, wherein said means for applying a load-balancing policy further comprises:

means for allowing a “

read”

operation on any of said plurality of servers; and

means for allowing a “

write”

operation on at least one of said plurality of servers, that is designated for “

read” and

“

write”

operations.

19. The system of claim 15, further comprising:

means for determining if at least one server in the plurality of servers is currently available to handle a request from the client; and

means for creating one or more reusable connection context objects in the connection pool for operational servers in the plurality of servers if no server is currently available to handle the request from the client.

20. The system of claim 15, wherein the means for providing a connection pool further comprises:

means for providing a connection pool hashtable, wherein a key for the connection pool hashtable is a uniform resource locator of the servers in the plurality of servers and a value for the connection pool hashtable is a context for the servers in the plurality of servers.

21. A computer-usable medium having computer-executable instructions for providing highly available services, said computer-executable instructions comprising:

means for providing a connection pool, said connection pool including a connection for each of a plurality of servers, wherein the connection pool comprises a pool of reusable connection context objects, each reusable connection context object containing information about an associated directory server in the plurality of directory servers;

means for applying a load-balancing policy to said connection pool; and

means for assigning a reusable connection context object from said connection pool to a client, according to said load-balancing policy, in response to a request from the client; and

means for managing a content of the connection pool, wherein the means for managing the content of the connection pool comprises means for periodically waking a connection pool management thread that, for each connection in the connection pool;

determines if the connection in the connection pool was accessed during a previous sleep period of the connection pool management thread;

checks availability of a server associated with the connection if the connection was not accessed during a previous sleep period of the connection pool management thread;

maintains a reusable connection context object associated with the connection in the connection pool if the connection was accessed during the previous sleep period of the connection pool management thread or the check of the availability of the server results in an indication that the server is available; and

removes the reusable connection context object associated with the connection from the connection pool if the check of the availability results in an indication that the server is not available.

22. The computer-usable medium of claim 21, wherein the connection pool management thread further:

attempts to connect to at least one server of said plurality of servers that has a status indicating it was previously unavailable;

determining if a connection to the at least one server of said plurality of servers that has a status indicating it was previously unavailable is successfully made; and

adding a reusable connection context object to the connection pool for the at least one server if the connection is successfully made.

23. The computer-usable medium of claim 21, further comprising:

means for detecting a failed operation;

means for changing a stats of a server that corresponds to the assigned reusable connection context object; and

means for assigning another reusable connection context object from said connection pool to said client.

24. The computer-usable medium of claim 21, wherein said means for applying a load-balancing policy further comprises:

means for allowing a “

read”

operation on any of said plurality of servers; and

means for allowing a “

write”

operation on at least one of said plurality of servers, that is designated for “

read” and

“

write”

operations.

25. The computer usable medium of claim 21, wherein said computer-executable instructions further comprise:

means for determining if at least one server in the plurality of servers is currently available to handle a request from the client; and

means for creating one or more reusable connection context objects in the connection pool for operational servers in the plurality of servers if no server is currently available to handle the request from the client.

26. The computer usable medium of claim 21, wherein the means for providing a connection pool further comprises:

means for providing a connection pool hashtable, wherein a key for the connection pool hashtable is a uniform resource locator of the servers in the plurality of servers and a value for the connection pool hashtable is a context for the servers in the plurality of servers.