Resource groups are used to apply security privileges and to aggregate resources for monitoring or administration. Groups can be mixed group types, most often used for security, or compatible groups that allow for aggregate monitoring and administration.
"Mixed" groups contain hetergenous resources of any number of resource types.
"Compatible" groups contain only resources of a specific type (say, JBoss AS Servers or Linux platforms).
Groups can be "recursive" (meaning all of the group members' child resources are implicitly added to the group). Recursive groups allow simpler security configurations which in turn allow you to, for example, assign read-only rights to everything on a single box.
"DynaGroups" are a query-oriented automatic system for generating groups by pivoted queries and can be used to easily create groups according to resource names, types, parents and configurations. (e.g. you can use this to dynamically build a group containing all datasources connected to a specific database).
The following are concepts that relate to RHQ's grouping functionality.
RHQ enables flexible group membership policies. You can add resources to a group one by one for fine-grained membership control.
You can also create expressions / rules that dynamically maintain group membership (DynaGroups)
You can control access to resources in your inventory by using groups. By using DynaGroups, you can effectively create dynamic ACLs (access control lists) to lessen the burden of security maintenance, especially against large inventories.
You can view the list of groups which also provides a quick view of the availability status of members of each group. A search bar is provided to allow you to search for specified groups.
Compatible groups (those composed entirely of the same type of resource have additional features available to them:
Group-wise availability
Viewing minimum, maximum and average metrics aggregated across all group members
Invoking operations on all group members
Fine-grained changes to connection properties and resource configuration across the group