The following diagram illustrates a portion of Zenoss' standard device class hierarchy. (A device class is a special type of organizer used to manage how the system models and monitors devices.)

#

Figure 5.1. Device Class Hierarchy

At the root of the device hierarchy is the Devices object. All device class zProperties are defined here, and their values are the default values for the entire hierarchy.

The illustration further shows two defined zProperties:

Through inheritance, properties defined at the root of the hierarchy apply to all objects beneath that node. So, at the /Devices/Server/Linux level of the device class hierarchy, the value of these two properties is the same as at /Devices, even though the property is not set explicitly at /Devices/Server/Linux. Inheritance simplifies system configuration, because default values set at the root level apply to all devices irrespective of their device class.

To further customize the system, you can change a specific zProperty further down the hierarchy without having to change the definitions of other zProperties. As shown in the following illustration, the value of zWmiMonitorIgnore is changed so that WMI monitoring is performed at the /Devices/Server/Windows level.

#

Figure 5.2. Device Class Hierarchy - Locally Defined Value (Override)

This locally defined value for zWmiMonitorIgnore overrides the value set at the root of the hierarchy. No other properties at this level are affected by this local change; they continue to inherit the value set at the root.

zProperties allow you to configure the system at a very granular level, down to a particular device. For example, in the following illustration, the device named dev.zenoss.com has the value of SNMP community set to private. This overrides the root value (public).

#

Figure 5.3. Device Class Hierarchy - Value Set on Device

If you change the SNMP Community value of dev.zenoss.com to public, it matches the value set at the root, but is still explicitly defined. Only if you remove the locally defined property does it again inherit the value of the property set at the root.

#1.1.1. User Interface View

This section further illustrates the characteristics of zProperties from the user interface perspective. The following screen shows zProperties defined at the root level.

#

Figure 5.4. Defined zProperties - Root Level

As shown in the previous screen, the zCollectorClientTimeout zProperty has a default value of 180. In the next screen, the value has been set to 170 at /Devices/Server/Linux, overriding the default value at this node of the hierarchy.

#

Figure 5.5. zCollectorClientTimeout zProperty - Local Value Set

To then remove the override and once again inherit the value from the root of the hierarchy, go to the Delete Local Property area of the zProperties page.

#

Figure 5.6. Delete Local Property

zProperties can be one of these types:

To access Event zProperties, from the left navigation menu, select Event and click the zProperties tab. You can also set zProperties for any event class in the events hierarchy by navigating to the level in the event hierarchy where you want to set the zProperty and clicking the zProperties tab.

To access Device zProperties, from the left navigational menu, select Devices and then click the zProperties tab. You can also select any of the Device Classes and the zProperties tab to set zProperties anywhere in the Device hierarchy. To set zProperties for an individual Device, navigate to that device, open the page menu, select the More option and then the zProperties tab.

To access Service zProperties, from the left navigation menu, select Services, and then click the zProperties tab. You can also access the Service zProperties tab anywhere in the services hierarchy by going to the level where you want to set the zProperty and clicking the zProperties tab.

To access Process zProperties, from the left navigation menu, select Processes, and then click the zProperties tab. You can also access the Process zProperties tab anywhere in the processes hierarchy by going to the level where you want to set the zProperty and clicking the zProperties tab.

To access Network zProperties, from the left navigation menu, select Networks, and then click the zProperties tab. You can also access the zProperties tab for any sub-network that exists with in the Networks page.