Compiling configurations in Azure Automation DSC

You can compile Desired State Configuration (DSC) configurations in two ways with Azure Automation: in the Azure portal, and with Windows PowerShell. The following table helps you determine when to use which method based on the characteristics of each:

Azure portal

  • Simplest method with interactive user interface
  • Form to provide simple parameter values
  • Easily track job state
  • Access authenticated with Azure logon

Windows PowerShell

  • Call from command line with Windows PowerShell cmdlets
  • Can be included in automated solution with multiple steps
  • Provide simple and complex parameter values
  • Track job state
  • Client required to support PowerShell cmdlets
  • Pass ConfigurationData
  • Compile configurations that use credentials

Once you have decided on a compilation method, you can follow the respective procedures below to start compiling.

Compiling a DSC Configuration with the Azure portal

  1. From your Automation account, click DSC Configurations.
  2. Click a configuration to open its blade.
  3. Click Compile.
  4. If the configuration has no parameters, you are prompted to confirm whether you want to compile it. If the configuration has parameters, the Compile Configuration blade opens so you can provide parameter values. See the Basic Parameters section below for further details on parameters.
  5. The Compilation Job blade is opened so that you can track the compilation job's status, and the node configurations (MOF configuration documents) it caused to be placed on the Azure Automation DSC Pull Server.

Compiling a DSC Configuration with Windows PowerShell

You can use Start-AzureRmAutomationDscCompilationJob to start compiling with Windows PowerShell. The following sample code starts compilation of a DSC configuration called SampleConfig.

Start-AzureRmAutomationDscCompilationJob -ResourceGroupName "MyResourceGroup" -AutomationAccountName "MyAutomationAccount" -ConfigurationName "SampleConfig"

Start-AzureRmAutomationDscCompilationJob returns a compilation job object that you can use to track its status. You can then use this compilation job object with Get-AzureRmAutomationDscCompilationJob to determine the status of the compilation job, and Get-AzureRmAutomationDscCompilationJobOutput to view its streams (output). The following sample code starts compilation of the SampleConfig configuration, waits until it has completed, and then displays its streams.

$CompilationJob = Start-AzureRmAutomationDscCompilationJob -ResourceGroupName "MyResourceGroup" -AutomationAccountName "MyAutomationAccount" -ConfigurationName "SampleConfig"

while($CompilationJob.EndTime –eq $null -and $CompilationJob.Exception –eq $null)
{
    $CompilationJob = $CompilationJob | Get-AzureRmAutomationDscCompilationJob
    Start-Sleep -Seconds 3
}

$CompilationJob | Get-AzureRmAutomationDscCompilationJobOutput –Stream Any

Basic Parameters

Parameter declaration in DSC configurations, including parameter types and properties, works the same as in Azure Automation runbooks. See Starting a runbook in Azure Automation to learn more about runbook parameters.

The following example uses two parameters called FeatureName and IsPresent, to determine the values of properties in the ParametersExample.sample node configuration, generated during compilation.

Configuration ParametersExample
{
    param(
        [Parameter(Mandatory=$true)]

        [string] $FeatureName,

        [Parameter(Mandatory=$true)]
        [boolean] $IsPresent
    )

    $EnsureString = "Present"
    if($IsPresent -eq $false)
    {
        $EnsureString = "Absent"
    }

    Node "sample"
    {
        WindowsFeature ($FeatureName + "Feature")
        {
            Ensure = $EnsureString
            Name = $FeatureName
        }
    }
}

You can compile DSC Configurations that use basic parameters in the Azure Automation DSC portal, or with Azure PowerShell:

Portal

In the portal, you can enter parameter values after clicking Compile.

alt text

PowerShell

PowerShell requires parameters in a hashtable where the key matches the parameter name, and the value equals the parameter value.

$Parameters = @{
    "FeatureName" = "Web-Server"
    "IsPresent" = $False
}

Start-AzureRmAutomationDscCompilationJob -ResourceGroupName "MyResourceGroup" -AutomationAccountName "MyAutomationAccount" -ConfigurationName "ParametersExample" -Parameters $Parameters

For information about passing PSCredentials as parameters, see Credential Assets below.

Composite Resources

Composite Resources allow you to use DSC configurations as nested resources inside of a configuration. This enables you to apply multiple configurations to a single resource. See Composite resources: Using a DSC configuration as a resource to learn more about Composite Resources

Note

In order for Composite Resources to compile correctly, you must first ensure that any DSC Resources that the composite relies on are first installed in the Azure Automation Account Modules repository or it will not import properly.

To add a DSC Composite Resource, you must add the resource module to an archive (*.zip). Go to the Modules repository on your Azure Automation Account. Then click on the 'Add a Module' button.

Add Module

Navigate to the directory where your archive is located. Select the archive file, and click OK.

Select Module

You will then be taken back to the modules directory, where you can monitor the status of your Composite Resource while it unpacks and registers with Azure Automation.

Import Composite Resource

Once the module is registered, you can then click on it to validate that the Composite Resources are now available to be used in a configuration.

Validate Composite Resource

Then you can call the Composite Resource into your configuration like so:


    Node ($AllNodes.Where{$_.Role -eq "WebServer"}).NodeName
    {

            JoinDomain DomainJoin
            {
                DomainName = $DomainName
                Admincreds = $Admincreds
            }

            PSWAWebServer InstallPSWAWebServer
            {
                DependsOn = "[JoinDomain]DomainJoin"
            }        
    }

ConfigurationData

ConfigurationData allows you to separate structural configuration from any environment specific configuration while using PowerShell DSC. See Separating "What" from "Where" in PowerShell DSC to learn more about ConfigurationData.

Note

You can use ConfigurationData when compiling in Azure Automation DSC using Azure PowerShell, but not in the Azure portal.

The following example DSC configuration uses ConfigurationData via the $ConfigurationData and $AllNodes keywords. You'll also need the xWebAdministration module for this example:

Configuration ConfigurationDataSample
{
    Import-DscResource -ModuleName xWebAdministration -Name MSFT_xWebsite

    Write-Verbose $ConfigurationData.NonNodeData.SomeMessage

    Node $AllNodes.Where{$_.Role -eq "WebServer"}.NodeName
    {
        xWebsite Site
        {
            Name = $Node.SiteName
            PhysicalPath = $Node.SiteContents
            Ensure   = "Present"
        }
    }
}

You can compile the DSC configuration above with PowerShell. The below PowerShell adds two node configurations to the Azure Automation DSC Pull Server: ConfigurationDataSample.MyVM1 and ConfigurationDataSample.MyVM3:

$ConfigData = @{
    AllNodes = @(
        @{
            NodeName = "MyVM1"
            Role = "WebServer"
        },
        @{
            NodeName = "MyVM2"
            Role = "SQLServer"
        },
        @{
            NodeName = "MyVM3"
            Role = "WebServer"
        }
    )

    NonNodeData = @{
        SomeMessage = "I love Azure Automation DSC!"
    }
}

Start-AzureRmAutomationDscCompilationJob -ResourceGroupName "MyResourceGroup" -AutomationAccountName "MyAutomationAccount" -ConfigurationName "ConfigurationDataSample" -ConfigurationData $ConfigData

Assets

Asset references are the same in Azure Automation DSC configurations and runbooks. See the following for more information:

Credential Assets

While DSC configurations in Azure Automation can reference credential assets using Get-AzureRmAutomationCredential, credential assets can also be passed in via parameters, if desired. If a configuration takes a parameter of PSCredential type, then you need to pass the string name of an Azure Automation credential asset as that parameter’s value, rather than a PSCredential object. Behind the scenes, the Azure Automation credential asset with that name will be retrieved and passed to the configuration.

Keeping credentials secure in node configurations (MOF configuration documents) requires encrypting the credentials in the node configuration MOF file. Azure Automation takes this one step further and encrypts the entire MOF file. However, currently you must tell PowerShell DSC it is okay for credentials to be outputted in plain text during node configuration MOF generation, because PowerShell DSC doesn’t know that Azure Automation will be encrypting the entire MOF file after its generation via a compilation job.

You can tell PowerShell DSC that it is okay for credentials to be outputted in plain text in the generated node configuration MOFs using ConfigurationData. You should pass PSDscAllowPlainTextPassword = $true via ConfigurationData for each node block’s name that appears in the DSC configuration and uses credentials.

The following example shows a DSC configuration that uses an Automation credential asset.

Configuration CredentialSample
{
    $Cred = Get-AzureRmAutomationCredential -ResourceGroupName "ResourceGroup01" -AutomationAccountName "AutomationAcct" -Name "SomeCredentialAsset"

    Node $AllNodes.NodeName
    {
        File ExampleFile
        {
            SourcePath = "\\Server\share\path\file.ext"
            DestinationPath = "C:\destinationPath"
            Credential = $Cred
        }
    }
}

You can compile the DSC configuration above with PowerShell. The below PowerShell adds two node configurations to the Azure Automation DSC Pull Server: CredentialSample.MyVM1 and CredentialSample.MyVM2.

$ConfigData = @{
    AllNodes = @(
        @{
            NodeName = "*"
            PSDscAllowPlainTextPassword = $True
        },
        @{
            NodeName = "MyVM1"
        },
        @{
            NodeName = "MyVM2"
        }
    )
}

Start-AzureRmAutomationDscCompilationJob -ResourceGroupName "MyResourceGroup" -AutomationAccountName "MyAutomationAccount" -ConfigurationName "CredentialSample" -ConfigurationData $ConfigData

Importing node configurations

You can also import node configurations (MOFs) that you have compiled outside of Azure. One advantage of this is that node configurations can be signed. A signed node configuration is verified locally on a managed node by the DSC agent, ensuring that the configuration being applied to the node comes from an authorized source.

Note

You can use import signed configurations into your Azure Automation account, but Azure Automation does not currently support compiling signed configurations.

Note

A node configuration file must be no larger than 1 MB to allow it to be imported into Azure Automation.

You can learn how to sign node configurations at https://msdn.microsoft.com/en-us/powershell/wmf/5.1/dsc-improvements#how-to-sign-configuration-and-module.

Importing a node configuration in the Azure portal

  1. From your Automation account, click DSC node configurations.

    DSC node configurations

  2. In the DSC node configurations blade, click Add a NodeConfiguration.
  3. In the Import blade, click the folder icon next to the Node Configuration File textbox to browse for a node configuration file (MOF) on your local computer.

    Browse for local file

  4. Enter a name in the Configuration Name textbox. This name must match the name of the configuration from which the node configuration was compiled.
  5. Click OK.

Importing a node configuration with PowerShell

You can use the Import-AzureRmAutomationDscNodeConfiguration cmdlet to import a node configuration into your automation account.

Import-AzureRmAutomationDscNodeConfiguration -AutomationAccountName "MyAutomationAccount" -ResourceGroupName "MyResourceGroup" -ConfigurationName "MyNodeConfiguration" -Path "C:\MyConfigurations\TestVM1.mof"