Understanding dynamic group definitions

Understanding dynamic groups

Dynamic group definitions

As described in About group configuration, a dynamic group is a group to which devices are assigned automatically. To set up a dynamic group, you must define it, that is, set up the criteria against which devices are evaluated to determine their membership in the group.

A dynamic group definition is somewhat like a rule in an email program that determines into which folder an incoming email message is placed. In many email programs, incoming messages are placed by default in the main inbox folder. In order to better organize his or her incoming messages, the program's user can create a rule to evaluate incoming messages and place them in different folders as they arrive, depending on criteria such as the sender or the subject. In a similar fashion, the Questra IDM Application Suite allows you to create a dynamic group definition that specifies how devices will be automatically organized into groups when those devices are manually created or provide information to the Enterprise.

In an important way, a dynamic group definition is much more powerful than a simple email rule. Most email rules merely dictate where to place incoming messages. The folders into which messages are placed must already exist; the rules do not create the folders. By contrast, a dynamic group definition does cause groups to be created. The first time a device is found that matches the membership criteria for a dynamic group, that group is created and appears on the Groups panel of the Navigation pane. All dynamic groups appear as green folders . (See also Types of groups.)

About built-in membership rules

The membership rules you will set up when defining a dynamic group will control which devices are selected for membership in a dynamic group. The built-in rules are described below.

NOTE: Generally speaking, you should keep a dynamic group hierarchy simple so that users can easily navigate through it. A good "rule of thumb" when setting up a dynamic group definition is to use only one or two of the built-in membership rules in combination in order to yield an easy-to-navigate group hierarchy.

ALERTSTATUS– This rule selects devices for groups according to the status of certain alerts associated with them. For example, you can define a dynamic group for devices for which there exist Submitted alerts, a type of active alert. To achieve this subgroup hierarchy (figure below), select the ALERTSTATUS property on the Dynamic Group Definitions dialog; in the Value field, enter Submitted. Alternatively, if you wanted to define dynamic groups for all alert statuses, just leave the Value field blank.(For more information on alert statuses, see Alerts and Alarms - An Overview.)
ALERTNAME– This rule selects devices for groups according to the names of alerts associated with them. To achieve this subgroup hierarchy (figure below), select the ALERTNAME property on the Dynamic Group Definitions dialog; leave the Value field blank. (For more information on alert names, see Configuring alerts.)
CONFIGURATION – This rule selects devices for groups according to their defined configurations. You do not need to (and in fact cannot) specify any particular configuration. As illustration, assume there are three configurations in your system, Manager Laptop, Sales Laptop, and Developer Laptop, and that you'd like to group devices by these configurations under the parent static Root group (figure below). To achieve this subgroup hierarchy, select the CONFIGURATION property on the Dynamic Group Definitions dialog. (For more information on defined configurations, see the topics in the Configuration Management Database book.
DEVICETYPE – This rule selects devices for groups according to their device types (categories used to define devices that share similar characteristics or capabilities). You do not need to specify any particular device type. To use a very simple example, assume there are three device types in your system, Bicycle, Unicycle, and Skateboard, and that you'd like to group devices by device type under the parent static Root group (figure below). To achieve this subgroup hierarchy, select the DEVICETYPE property on the Dynamic Group Definitions dialog.

About custom membership rules

Besides the built-in rules (above), you can set up additional rules by which to evaluate devices for group membership. To continue the example of organizing by device type, assume that bicycles, unicycles, and skateboards come in different colors and that you'd like to group the devices further by their color within their device type (figure below).

But where do the custom rules comes from? In order for custom rules to appear under Subgroup Hierarchy on the Dynamic Group Definitions dialog, two constructs must be set up first.

Assume you wanted to set up the group structure shown above. First, you would edit each device type itself so that you added a property whose name is Color and whose Property Use is set to Registration. (For more on how to define device type properties, see Defining the properties of a device type.)

Next, if you manually added some devices, you would add to each one an extended property whose name is Color and whose value is the device's color. Be consistent, such as always capitalize the value. It is these values that become the names of the dynamic groups. (For more on how to define extended device properties, see Defining extended properties for a device.)

Having defined those constructs, you would see Color listed under the Subgroup Hierarchy on the Dynamic Group Definitions dialog. You would then select Color and leave the Value field blank in order to group by all colors. (You would also be sure to leave the Value field blank for the built-in membership rule DEVICETYPE.)