Application Groups

Application Groups (APG) are active automation elements that manage the availability of a small set of applications.

For example, a group might be all the resources that are needed to run a CICS® or an IMS. Or, at a higher level, a group might be a complete application, consisting of subgroups to manage the complex resources that are needed to make the application work.

The advantages of groups are that they automatically manage the availability of the resources they are looking after. They provide you with a single point of control to request that the resources are stopped or started. The down side is that if an operator does not tell the groups what he wants, the groups can end up working at cross purposes.

Application group types

There are three types of Application Groups (APG) available within SA z/OS:

BASIC: In a BASIC application group, all of its components must be available before the group is considered to be available.
MOVE: In a MOVE application group, exactly one of its components must be available before the group is considered to be available. In MOVE groups, you can specify alternative components to start if their primary component fails to start.
SERVER: In a SERVER application group, any number of components can be specified that must be available before the group is considered to be available. In SERVER groups, you can specify what happens if their components fail to start.

For more information of application group, see Grouping support.

Relationships

Relationships for a group work on the group and are passed onto the group’s members.

If a group is a child of a resource, every member of the group is also considered to be a child of the resource, when SA z/OS works out what can be stopped and started. There is an exception for Move and Server groups. Move and Server groups allow their members to be stopped (provided the group as a whole is not being stopped) while their stop dependency is unsatisfied. The set of active members of the Move and Server groups can be changed.

Runmodes

Runmodes are not groups, but they can provide a similar function at some levels.

Runmodes are defined as sets of runtokens that are used to tag individual resources. You then select the runmode that you want to be active on a system. The INGRUN command can be used to activate or deactivate a particular runmode. It is suggested that runmodes rather than large groups of unrelated resources are used for "bulk" application control on a system.

For more information about Runmodes, see Using Runmodes in IBM Z® System Automation User's Guide.