Method and apparatus for updating application servers

A data processing system for managing a set of servers, the data processing system comprising:

• creating means, responsive to an indication that an alteration of an application on the set of servers providing a service is to occur, for creating a first group of servers and a second group servers from the set of servers, wherein the first group is designated for handling ongoing sessions with an unaltered application;
• altering means for altering the application on the second group;
• and
• transitioning means for transitioning a server from the first group to the second group as ongoing sessions handled in the first group decrease in number to form a transitioned server, wherein the alteration of the application is performed without interrupting the service.

A computer program product for managing a set of servers, the computer program product comprising:

• first instructions, responsive to an indication that an alteration of an application on the set of servers providing a service is to occur, for creating a first group of servers and a second group servers from the set of servers, wherein the first group is designated for handling ongoing sessions with an unaltered application;
• second instructions for altering the application on the second group;
• and
• third instructions for transitioning a server from the first group to the second group as ongoing sessions handled in the first group decrease in number to form a transitioned server, wherein the alteration of the application is performed without interrupting the service.