What is a resource group?

Resource groups are the central unit in System Automation for Multiplatforms. They are logical containers for a collection of resources that can be treated as one logical instance:
  • You can use resource groups to control all of their members collectively. For example if you set the NominalState of a resource group to online all members are started and kept online. If you set the NominalState to offline all members are stopped and kept offline.
  • You can monitor their OpState, which provides a consolidation of the OpStates of the individual resource group members.
Members of a resource group can be of type:
  • Serial fixed.
  • Serial floating.
  • Serial concurrent.
  • And even resource groups itself which means that nested groups can be defined.

An example of a resource group containing fixed resources is a resource group RG_Fix which contains serial fixed resources. These are a web server FixWebServer which can only run on node1, and a database resource FixDB2 located on node2.

Figure 1. Example of a resource group containing fixed resources
Example for a resource group containing fixed resources
In order to start both resources FixWebServer and FixDB2, set the NominalState of RG_Fix to Online. This example also shows that System Automation for Multiplatforms can handle resource group members that are distributed on different nodes in a cluster.

An example for floating resource group members is the following: A web server apache1 could run either on node1, node2, or node3. The resource group RG_WebApp would look very similar except that the web server could be started on either of the three nodes

Figure 2. Example of a resource group that contains a mixture of members of different resource types
Example for a resource group that contains a mixture of members of different resource types
This example shows that resource groups can contain a mixture of members of different resource types.

The concept of resource groups is very powerful as it allows defining resource groups as members of other resource groups. An example is resource group RG_A which has as members resource A, which is a fixed resource, and RG_WebApp, the resource group from the previous example. Nested resource groups allow structuring complex environments in several layers. The nesting level is 50.

Another flexibility of the resource groups functionality is that all kinds of relationships like start or stop relationships and location constraint relationships can be defined with resource groups as source or target resource. Furthermore it is allowed that resource group members can be part of such relationships as source or target resource.

Resource groups are defined in System Automation for Multiplatforms resource class IBM.ResourceGroup.