Often times, IT Pros want to automate software installation and configuration upon a machine’s initial boot-up. This blog will walk you through how to use Windows PowerShell Desired State Configuration (DSC) to do this. We will show you how to prepare and inject DSC configurations into your bootable media (such as VHDs), so that they are executed during the initial boot-up process. We will discuss three approaches to this process, and give a VHD example for each one.<\/p>\n
Prerequisites<\/strong>:<\/p>\n Option 1 – Inject a DSC configuration (.ps1) into a VHD <\/strong><\/p>\n Our first approach will be to inject a .ps1 with a DSC configuration directly into a VHD. This approach leverages “Unattended Windows Setup” to automatically run an inserted configuration. For information about running Windows Setup, see the reference here.<\/span><\/a><\/p>\n <\/p>\n powershell<\/span><\/span><\/span> -c<\/span> {<\/span><\/p>\n <\/span>configuration<\/span><\/span> SampleIISInstall<\/span><\/span><\/span><\/p>\n <\/span>{<\/span><\/p>\n <\/span>node<\/span> (“localhost<\/span>“<\/span>)<\/span><\/p>\n <\/span>{<\/span><\/p>\n <\/span>WindowsFeature<\/span> IIS<\/span><\/span><\/p>\n <\/span>{<\/span><\/p>\n <\/span>Ensure =<\/span> “Present”<\/span><\/span><\/p>\n <\/span>Name =<\/span> “Web-Server”<\/span> <\/span><\/span><\/p>\n <\/span>}<\/span><\/p>\n <\/span>}<\/span><\/p>\n <\/span>}<\/span><\/p>\n <\/span><\/span><\/p>\n <\/span># Compile the configuration file to a MOF format<\/span><\/span><\/p>\n <\/span>SampleIISInstall<\/span><\/span><\/span><\/p>\n <\/span><\/p>\n <\/span># Run the configuration on localhost<\/span><\/span><\/span><\/p>\n <\/span>Start-DscConfiguration<\/span><\/span> -Path<\/span> .\\SampleIISInstall<\/span><\/span> –ComputerName<\/span><\/span> localhost<\/span><\/span> -Wait<\/span> -Force<\/span> -Verbose<\/span> <\/span><\/p>\n } <\/span><\/p>\n <\/p>\n <settings pass=”specialize”><\/span><\/p>\n <\/span><component name=”Microsoft-Windows-Deployment” processorArchitecture<\/span>=”amd64″ …><\/span><\/p>\n <\/span><RunSynchronous<\/span>><\/span><\/p>\n <\/span><RunSynchronousCommand<\/span>><\/span><\/p>\n <\/span><Order>1<\/Order><\/span><\/p>\n <\/span><Path>%SystemDrive<\/span>%\\DSC\\RunDSC.cmd<\/strong><\/Path><\/span><\/p>\n <\/span><\/RunSynchronousCommand<\/span>><\/span><\/p>\n <\/span><\/RunSynchronous<\/span>><\/span><\/p>\n <\/span><\/component><\/span><\/p>\n <\/settings><\/span><\/p>\n schtasks.exe \/Create \/SC ONSTART \/TN “\\Microsoft\\Windows\\Desired State Configuration\\DSCRestartBootTask<\/span>” \/RU System <\/strong>\/F \/TR “PowerShell.exe –ExecutionPolicy<\/span> RemoteSigned<\/span> -File c:\\dsc\\SampleIISInstall.ps1″<\/p>\n Option 2 – Inject a compiled DSC configuration (.mof) into a VHD<\/strong><\/p>\n Imagine we need to customize the installation for large-scale rollouts so that we achieve consistency in the configuration of each target node. The method described in Option 1 does not seem to be efficient; it requires the compilation of the DSC configuration on each node. In the following approach, we inject an already compiled configuration into the VHD.<\/p>\n There are two ways to inject a complied DSC configuration to VHD. Let’s go through them.<\/p>\n 2.1 Inject a DSC configuration (.mof) document<\/strong><\/p>\n PS C:<\/span>\\> SampleIISInstall<\/span><\/span><\/p>\n <\/span><\/p>\n <\/span><\/p>\n <\/span>Directory: C:\\SampleIISInstall<\/span><\/p>\n <\/span><\/p>\n <\/span><\/p>\n Mode <\/span>LastWriteTime<\/span> <\/span> <\/span>Length Name<\/span><\/p>\n —- <\/span>————- <\/span> <\/span>—— —-<\/span><\/p>\n -a— <\/span>2\/14\/2014 <\/span>4:12 PM <\/span>1086 localhost.mof<\/span><\/span><\/p>\n <\/span><\/span><\/p>\n<\/div>\n schtasks.exe \/Create \/SC ONSTART \/TN “\\Microsoft\\Windows\\Desired State Configuration\\DSCRestartBootTask<\/span>” \/RU System \/F \/TR “PowerShell.exe –NonInt<\/span> -Command ‘Invoke-CimMethod<\/span> -Namespace root\/Microsoft\/Windows\/DesiredStateConfiguration<\/span> –ClassName<\/span> MSFT_DSCLocalConfigurationManager<\/span> –MethodName<\/span> PerformRequiredConfigurationChecks<\/span> –Arg<\/span> @{<\/span>Flags = [System.UInt32]3 }'”<\/p>\n The above process will make localhost.mof the pending configuration in the LCM. The scheduled task then tells the LCM to process the pending configuration (“Flag 3” means to apply the configuration). Through this mechanism, localhost.mof will be applied.<\/p>\n 2.2 Inject a “meta-configuration” to download a document <\/strong><\/p>\n In the above we discussed how to apply configurations using the “push model<\/span><\/a>” of DSC. That is to say, we “pushed” the configuration onto the machine. We can also leverage the “pull model<\/span><\/a>” of DSC to apply a configuration. To do this, we must configure the node to “pull” it’s configuration from a DSC “pull server<\/span><\/a>” and then apply it. We do this by configuring the Local Configuration Manager with a “meta-configuration.”<\/p>\n We describe the steps as below:<\/p>\n 1. Deploy your configuration files to the pull server (see this blog<\/span><\/a> for more information)<\/p>\n Now we have the configuration files ready on the pull server. Next, we will create a DSC meta-configuration to be injected to the VHD.<\/p>\n 2. Prepare the meta-configuration for target node<\/p>\n\n
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