System Center Configuration Manager 2007 : Configuration Manager and WMI (part 4) - Hardware Inventory Through WMI

The Root\CCM Namespace

The ConfigMgr client also uses WMI for internal control of its own operations. ConfigMgr 2007 creates and uses several namespaces in addition to adding classes to the Root\CIMV2 namespace.

The most important namespace created by the ConfigMgr client is the Root\CCM namespace. Together with several namespaces under Root\CCM, this namespace holds the configuration and policies that govern the operation of the ConfigMgr client. The hardware inventory process uses a policy stored in the Root\CCM\Policy\Machine namespace to specify what inventory data to retrieve from managed objects defined in the Root\CIMV2 namespace. “The Configuration Manager Client WMI Namespace” section discusses additional uses of the Root\CCM namespace.

Hardware Inventory Through WMI

ConfigMgr uses two MOF files to control hardware inventory:

• SMS_Def.mof— Specifies the information reported to the management point during the client inventory retrieval cycle. The actual SMS_Def.mof file is not downloaded to the ConfigMgr client. Instead, the client receives changes to reporting class configuration as part of its machine policy. 

• Configuration.mof— Defines custom data classes the hardware inventory client agent will inventory. In addition to standard WMI classes, such as the Win32 classes, you can create data classes to provide inventory data that is accessible through WMI, such as data from the client’s system Registry. ConfigMgr clients download the Configuration.mof file as part of their machine policy retrieval cycle. Any changes are compiled and loaded into the WMI repository.

The ConfigMgr client stores its machine policy in the Root\CCM\Policy\Machine WMI namespace. You can use the WMI Object Browser from the WMI Administrative Tools to examine some to the inventory-related objects in this namespace. To launch the WMI Object Browser and connect to the ConfigMgr machine policy namespace, perform the following steps:

You can locate objects of a specified class by clicking the Browse button (the binocular icon on the toolbar above the left pane). As an example, select InventoryDataItem from the available classes, as shown in Figure 14. InventoryDataItem is the class representing inventory items specified in the machine policy. Click the Browse button to display a list of InventoryDataItem instances in the Machine Policy namespace, as shown in Figure 15.

Figure 14. Browsing for InventoryDataItem in the WMI Object Browser

Figure 15. InventoryDataItem instances listed in the WMI Object Browser

Figure 15 has the columns resized to hide the Key (1) column, which displays an object GUID (Globally Unique Identifier), and to display the more interesting information in Key (2) and Key (3).

Selecting the instance that refers to the Win32_DiskDrive class in the Root\CIMV2 namespace and double-clicking this entry displays the instance properties shown in Figure 16. The Namespace and ItemClass properties tell the hardware inventory agent it can retrieve inventory data for this class from Win32_DiskDrive objects in the Root\CIMV2 namespace.

Figure 16. Properties of the Win32_DiskDrive instance of the InventoryDataItem as displayed in the WMI Object Browser

The Properties property contains a list of properties to inventory from each instance of Root\CIMV2\Win32_DiskDrive. Here are the properties listed:

Availability, Description, DeviceID, Index, InterfaceType, Manufacturer, MediaType, Model, Name, Partitions, PNPDeviceID, SCSIBus, SCSILogicalUnit, SCSIPort, SCSITargetId, Size, SystemName

Win32_DiskDrive objects have many other properties besides these. If you examine the default SMS_Def.mof file that comes with ConfigMgr, you will find a section starting with the following:

[ SMS_Report     (TRUE),
  SMS_Group_Name ("Disk"),
  SMS_Class_ID   ("MICROSOFT|DISK|1.0") ]

class Win32_DiskDrive : SMS_Class_Template

This section is followed by a list of inventory properties available for the Win32_DiskDrive class. The properties listed here correspond to the ones designated with “SMS_Report (TRUE)” in the SMS_Def.mof file. SMS_Report is a class qualifier defined in the SMS_Class_Template class definition in SMS_Def.mof. If you change the SMS_Report qualifier on any of the available inventory properties in SMS_Def.mof on the site server, the corresponding WMI InventoryDataItem instance in the machine policy namespace is updated on the client during the next machine policy retrieval cycle.

Another InventoryDataItem instance in the Root\CCM\Policy\Machine namespace—Win32Reg_AddRemovePrograms—configures inventory settings for reporting on items of the Win32Reg_AddRemovePrograms class in the Root\CIMV2 namespace. Unlike Win32_DiskDrive, Win32Reg_AddRemovePrograms is not a default Win32 class; it is defined in the Configuration.mof file. The following is the MOF code for Win32Reg_AddRemovePrograms:

#pragma namespace ("\\\\.\\root\\cimv2")
[ dynamic,
  provider("RegProv"),
  ClassContext("local|HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows
\\CurrentVersion\\Uninstall")
]
class Win32Reg_AddRemovePrograms
{
    [key]
        string    ProdID;
    [PropertyContext("DisplayName")]
        string    DisplayName;
    [PropertyContext("InstallDate")]
        string    InstallDate;
    [PropertyContext("Publisher")  ]
        string    Publisher;
    [PropertyContext("DisplayVersion")]
        string    Version;
};

When the ConfigMgr client downloads and compiles the Configuration.mof file during its machine policy retrieval cycle, WMI adds this class to the Root\CIMV2 namespace. The class uses the Registry provider (RegProv) to retrieve the information stored under HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall in the local Registry dynamically. Each key under this location stores information about an item in Add/Remove Programs. This exposes these keys as managed objects of the newly compiled WMI class. The reporting class of the same name defined in SMS_Def.mof specifies what inventory data to report from these managed objects.

This example shows how the Configuration.mof and SMS_Def.mof files can be used together to add information from the system Registry to the ConfigMgr inventory. You can use similar methods to add data from any provider installed on the ConfigMgr client machines.