Ranking service units to provide and protect highly available services using the Nway redundancy model

• US 8,719,835 B2
• Filed: 05/16/2012
• Issued: 05/06/2014
• Est. Priority Date: 06/07/2011
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Kanso, Ali, Toeroe, Maria
• Primary Examiner(s): Kawsar, Abdullah Al
• Application Number:
  US13/472,616
• Publication Number:
  US 20120317437A1
• Time in Patent Office: 720 Days
• Field of Search: 718/104
• US Class Current: 718/105
• CPC Class Codes: G06F 11/2035 without idle spare hardware
• CPC Class Codes: G06F 9/5083 Techniques for rebalancing the load in a distributed system

Abstract

Presented are methods and apparatus for protecting a plurality of High Availability (HA) Service Instances (SIs) with a plurality of Service Units (SUs) with an Nway redundancy model. Any of the SUs associated with the Nway redundancy model can simultaneously be assigned an active HA state for some of the SIs and a standby HA state for other SIs. However, only one SU can have the active state for any given SI. The Nway redundancy model is a configured prior to runtime operation.

Claims

1. A method, stored in a memory and executing on a processor, for providing configuration for High Availability (HA) of a Service, said method comprising:

assigning roles to a plurality of Service Units (SUs) associated with a plurality of Service Instances (SIs) in a system configured to use an Nway redundancy model, wherein said Nway redundancy model is defined such that an SU can simultaneously be assigned an active role for one or more of said plurality of SIs, a standby role for one or more of said plurality of SIs, a backup active role for one or more of the plurality of Sis, and a backup standby role for one or more of the plurality of SIs, wherein the assigning is performed in a manner which enables a balanced distribution of SI load during runtime of the system both before and after a failure of one of the plurality of SUs;

configuring said plurality of SUs for redundant operation based on said assigned roles; and

wherein said assigning further comprises;

calculating an active role load, a backup active role load and a backup standby role load for each of said plurality of SUs wherein said calculating is constrained such that a sum of said active role load, said backup active role load and said backup standby role load for any one of said plurality of SUs is less than or equal to the backup standby role load of a corresponding SU;

calculating a standby role load range for each of said plurality of SUs; and

calculating a backup assignment role load for each of said plurality of SUs wherein said backup assignment role load is a constraint such that a sum of said active role load, said backup active role load and said backup standby role load for all SUs for which said each of said plurality of SUs is assigned is less than or equal to said backup assignment role load.

2. The method of claim 1, wherein said configuring further comprises:

assigning one or more active roles, associated with one or more of said plurality of SIs, to at least some of said plurality of SUs;

assigning one or more backup active roles, associated with one or more of said plurality of SIs, to at least some of said plurality of SUs wherein each of the SUs associated with said one or more backup active roles cannot be duplicated; and

assigning one or more standby roles, associated with one or more of said plurality of SIs, to at least some of said plurality of SUs.

3. The method of claim 1, wherein said calculating an active role load, a backup active role load and a backup standby role load further comprises:

dividing a number of said plurality of SIs by a number of said plurality of SUs;

truncating a quotient of said dividing to a whole number for use as a first active role load; and

if the result of the dividing is a non-integer, adding one to said first active role load for use as a second active role load.

4. The method of claim 1, wherein said calculating a standby role load further comprises:

dividing a number of said plurality of SIs by a number of said plurality of SUs;

multiplying a quotient of said dividing by a predetermined number of standby role assignments;

truncating a product of said multiplying to a whole number for use as a first standby role load; and

if the result of the dividing is a non-integer, adding one to said first standby role load for use as a second standby role load.

5. The method of claim 1, wherein said calculating a backup assignment role load further comprises:

dividing a number of said plurality of SIs by a number of said plurality of SUs and truncating a quotient of said dividing to a whole number;

multiplying said whole number by a sum of a predetermined number of standby role assignments and one for use as a first backup assignment role load; and

if the result of the dividing is a non-integer, multiplying a sum of said whole number and one by a sum of said predetermined number of standby role assignments and one for use as a second backup assignment role load.

6. The method of claim 1, wherein said active role load range, said backup active role load range and said standby role load range are equal for any given SU.

7. The method of claim 1, wherein a role of each SU associated with an SI has a predetermined ranking.

8. The method of claim 7, wherein said predetermined ranking from highest rank to lowest rank is Active, Backup Active, Standby and Backup Standby.

9. A computer system for providing configuration for High Availability (HA) of a Service, said computer system comprising:

a processor configured to assign roles to a plurality of Service Units (SUs) associated with a plurality of Service Instances (SIs) in a system configured to use an Nway redundancy model, wherein the assigning is performed in a manner which enables a balanced distribution of SI load during runtime of the system both before and after a failure of one of the plurality of SUs, wherein said Nway redundancy model is defined such that an SU can simultaneously be assigned an active role for one or more of said plurality of SIs, a standby role for one or more of said plurality of SIs, a backup active role for one or more of the plurality of SIs, and a backup standby role for one or more of the plurality of SIs;

wherein the processor is further adapted to configure said plurality of SUs for redundant operation based on said assigned roles; and

wherein said processor is further configured to assign the roles by calculating an active role load, a backup active role load and a backup standby role load for each of said plurality of SUs wherein said calculating is constrained such that a sum of said active role load, said backup active role load and said backup standby role load for each of said plurality of SUs is less than or equal to a corresponding backup standby role load, by calculating a standby role load range for each of said plurality of SUs; and

by calculating a backup assignment role load for each of said plurality of SUs wherein said backup assignment role load is a constraint such that a sum of said active role load, said backup active role load and said backup standby role load for all SUs for which said each of said plurality of SUs is assigned is less than or equal to said backup assignment role load.

10. The computer system of claim 9, wherein said processor is further adapted to configure the plurality of the SUs by assigning one or more active roles, associated with one or more of said plurality of SIs, to at least some of said plurality of SUs, by assigning one or more backup active roles, associated with one or more of said plurality of SIs, to at least some of said plurality of SUs wherein each the of SUs associated with said one or more backup active roles cannot be duplicated;

and by assigning one or more standby roles, associated with one or more of said plurality of SIs, to at least some of said plurality of SUs.

11. The computer system of claim 9, wherein said processor performs the calculating for an active role load, a backup active role load and a backup standby role load by dividing a number of said plurality of SIs by a number of said plurality of SUs, by truncating a quotient of said dividing to a whole number for use as a first active role load, and, if the result of the dividing is a non-integer, by adding one to said first active role load for use as a second active role load.

12. The computer system of claim 9, wherein said processor performs said calculating of a standby role load by dividing a number of said plurality of SIs by a number of said plurality of SUs, by multiplying a quotient of said dividing by a predetermined number of standby role assignments, by truncating a product of said multiplying to a whole number for use as a first standby role load;

and, if the result of the dividing is a non-integer, by adding one to said first standby role load for use as a second standby role load.

13. The computer system of claim 9, wherein said processor performs said calculating of a backup assignment role by dividing a number of said plurality of SIs by a number of said plurality of SUs and truncating a quotient of said dividing to a whole number;

by multiplying said whole number by a sum of a predetermined number of standby role assignments and one for use as a first backup assignment role load; and

, if the result of the dividing is a non-integer, by multiplying a sum of said whole number and one by a sum of said predetermined number of standby role assignments and one for use as a second backup assignment role load.

14. The computer system of claim 9, wherein said active role load range, said backup active role load range and said standby role load range are equal for any given SU.

15. The computer system of claim 11, wherein a role of each SU associated with an SI has a predetermined ranking.

16. The computer system of claim 15, wherein said predetermined ranking from highest rank to lowest rank is Active, Backup Active, Standby and Backup Standby.