{"id":1981,"date":"2013-11-15T12:21:00","date_gmt":"2013-11-15T12:21:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/powershell\/2013\/11\/15\/hungry-for-more-windows-powershell-desired-state-configuration-resources\/"},"modified":"2019-02-18T13:05:29","modified_gmt":"2019-02-18T20:05:29","slug":"hungry-for-more-windows-powershell-desired-state-configuration-resources","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/powershell\/hungry-for-more-windows-powershell-desired-state-configuration-resources\/","title":{"rendered":"Hungry for more Windows PowerShell Desired State Configuration Resources?"},"content":{"rendered":"

Now that you understand the <\/span>value and need of <\/span>Windows PowerShell Desired State Configuration <\/span>(DSC),<\/a> and how to declaratively express the intent of machine configuration via the new configuration keyword<\/a>, you might be wondering how the configuration happens.<\/span><\/p>\n

Configuration on a machine works because of DSC resources<\/a>. Windows Server 2012 R2 and Windows Management Framework (WMF) 4.0 come with 12 built-in resources<\/a>, but that’s not all. Like command extensibility of PowerShell, DSC resources are also extensible–you can create new DSC resources to fill the gap. <\/span>This blog will walk you through the mechanics of DSC resources, and how to create new custom DSC resources.<\/span><\/p>\n

The Desired State Configuration (DSC) resource is a PowerShell module that is used to model one or more entities that you want to be in a specific, desired state. In the below example, the DSC resource WindowsFeature<\/strong> is modeled to install or uninstall server roles such as Hyper-V, BranchCache, etc. on the target machine. <\/span><\/p>\n

\"image\"<\/a>  <\/span><\/p>\n

Resource naming convention<\/span><\/h2>\n

All the contents of a DSC resource are packaged in to a single directory, so you can deploy DSC resources by using x-copy. By convention, the directory in which the DSC resource is packaged should have the same name as that of the DSC resource. This package contains the following files:<\/span><\/p>\n

Resource definition file<\/span><\/span><\/h2>\n

The resource definition file defines the entity that you want to model. In this definition file, you model the properties of the entity that you want to expose with a CIM class definition. The CIM class should inherit from a base CIM class called OMI_BaseResource<\/strong>. The definition file has the same name as the CIM class, with a .schema.mof<\/strong> extension.<\/span><\/p>\n

In the below example, a DSC resource named MSFT_RoleResource<\/strong> has a CIM class named MSFT_RoleResource<\/strong> that inherits from OMI_BaseResource<\/strong> CimClass.<\/span><\/p>\n

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class MSFT_RoleResource<\/strong> : OMI_BaseResource<\/strong><\/span><\/p>\n

{<\/span><\/p>\n

};<\/span><\/p>\n<\/blockquote>\n

Friendly name<\/span><\/h2>\n

You can give a DSC resource a more user-friendly name for simplicity and readability by adding the FriendlyName<\/strong> attribute to the CIM class; this name represents the contract of the DSC resource. In the below example, MSFT_RoleResource<\/strong> has the friendly name WindowsFeature<\/strong>.<\/span><\/p>\n

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[ClassVersion(“1.0.0”), FriendlyName<\/strong>(“WindowsFeature”)] <\/span><\/p>\n

class MSFT_RoleResource : OMI_BaseResource<\/span><\/p>\n

{<\/span><\/p>\n

};<\/span><\/p>\n<\/blockquote>\n

 <\/span><\/p>\n

If a friendly name is specified for a DSC resource, then the same friendly name must be used in the configuration document to reference the DSC resource. Using the resource name to reference it in the configuration document is not supported. However if the friendly name is not specified in the resource definition file, then the resource name can be used in the configuration document.<\/span><\/p>\n

For more information about how resources are used to author the configuration document, refer to the following previous blog<\/a>.<\/span><\/p>\n

Qualifiers<\/span><\/h2>\n

Each property in a <\/span>CIM class can have one or more of the following qualifiers<\/a>: Key, Required, Read, and Write. The definition of each qualifier is as follows:<\/span><\/span><\/p>\n

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