Windows PowerShell DSC Classroom Series – 22/Dec/2019

PowerShell Desired State Configuration

  • In PowerShell Scripts
    • How to the work (Which cmdlet has to be used)
  • In PowerShell DSC
    • What has be done to complete this work
  • PowerShell DSC can be installed on the older versions of Windows (8,8.1, 2012) by installing Windows Management Framework 5.1.
  • In Windows 10, Windows Server 2016+ DSC is already enabled.
 $PSVersionTable.PSVersion
  • For Lab-Setup, Create a windows server 2016 core edition in AWS or Azure with t2.micro or B1s in Azure

Preview

Preview Preview

PowerShell DSC Setup on Local Dev Machine

  • Ensure PSDesiredStateConfiguration Module is installed on the Machine
Get-Command -Module PSDesiredStateConfiguration
  • Enable PowerShell Remoting on Windows
 Enable-PSRemoting -SkipNetworkProfileCheck -Force -Verbose
  • Lets try to login in the same machine Preview

PowerShell DSC Workflow for beginners

  • Create Configuration (Creating a PowerShell file with Specific Syntax)
  • Use Resources in Configuration to tell what has to be done
  • Execute Configuration to Create MOF file
  • Start the DSC Configuration by using MOF File as input

PowerShell DSC Visual Studio Code Setup

  • Install PowerShell Extension into VSCode.

Terms

  • Configuration:
    • Will define on which nodes the configuration has to be execute
    • It will also define what has to be done
  • Resource:
    • Smallest unit of PowerShell DSC which can perform actions
  • Node:
    • Is the machine where the configuration has to be applied
  • LCM (Local Configuration Manger):
    • Which is responsible for executing mof files.

Executing Sample PowerShell DSC

  • Create a new directory
mkdir helloworld
  • In this directory create a new ps1 file
New-Item helloworld.ps1
notepad helloworld.ps1
  • Write DSC Configuration in this file
Configuration MyDscConfiguration {

    Import-DscResource -ModuleName PSDesiredStateConfiguration

    Node "localhost" {
        File myfile
        {
            Ensure = "Present" # Ensure the directory is Present on the target node.
            Type = "Directory" # The default is File.
            DestinationPath = "C:\Testing"
        }

    }
}
MyDscConfiguration
  • Execute PS1 to create mof file
.\helloworld.ps1
ls

  • Now Execute DSC Configuration
Start-DscConfiguration -Path .\MyDscConfiguration -Wait -Verbose

Lets try to understand Configuration

Preview

Built-in DSC Resources

Exercise-1: Write PowerShell DSC Resource to Ensure Print Spooler Service is running

  • We have got the Service Dsc Resource
  • Now lets write the configuration
Configuration PrintSpoolerConfiguration {

    Import-DscResource -ModuleName PSDesiredStateConfiguration

    Node 'localhost' {
        Service Spooler {
            Name = 'Print Spooler'
            State = 'Running'
        }
    }
}

PrintSpoolerConfiguration
  • Now Execute this on localhost

Exercise-2: Install IIS Server on Windows Server

  • Follow the steps above to create a new ps1 file in a folder and write the configuration as shown below
Configuration WebServerConfiguration {

    Import-DscResource -ModuleName PSDesiredStateConfiguration

    Node 'localhost' {

        WindowsFeature 'iisinstall'{
            Name = 'web-server'
            Ensure = 'present'
        }
    }
}

WebServerConfiguration
  • Execute as mentioned above

Powershell Gallery

  • Along with built in resources, there are lot of Community DSC Modules which give DSC Resources. Refer Here
  • Sample Module Installations
Install-Module -Name cChoco

Exercise

  • Write a DSC Configuration to
    • Ensure a file is present in C:\temp\test.txt with content ‘Iam learning PowershellDSC’
    • Ensure a directory is present in c:\temp\dsc
    • copy c:\temp\dsc to c:\temp\dsccopy
    • Ensure Hyper-V is enabled as a windows feature (Windows 10 Professional)
    • Ensure Print Spooler is Running

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devops & cloud enthusiastic learner