Desired State Configuration (DSC) basics in PowerShell

Introduction

Desired State Configuration (DSC) helps you keep your computer or server set up the way you want it, automatically fixing things if they change.

You want to make sure a software is always installed on your computer.

You want a folder to always exist with certain files inside.

You want to keep a service running and restart it if it stops.

You want to set network settings the same way on many computers.

You want to automate setup tasks so you don't do them by hand every time.

Syntax

PowerShell

Configuration ConfigName {
    Node 'localhost' {
        ResourceName ResourceType {
            Property1 = 'Value1'
            Property2 = 'Value2'
        }
    }
}

ConfigName
Start-DscConfiguration -Path ./ConfigName -Wait -Verbose

A Configuration block defines the desired setup using resources.

Node specifies which computer(s) the configuration applies to.

Examples

This example ensures a folder named C:\Example exists on your computer.

PowerShell

Configuration SampleConfig {
    Node 'localhost' {
        File ExampleFolder {
            DestinationPath = 'C:\Example'
            Type = 'Directory'
            Ensure = 'Present'
        }
    }
}

SampleConfig
Start-DscConfiguration -Path ./SampleConfig -Wait -Verbose

This example installs Notepad++ if it is not already installed.

PowerShell

Configuration InstallNotepadPlusPlus {
    Node 'localhost' {
        Package NotepadPlusPlus {
            Name = 'Notepad++'
            Path = 'C:\Installers\npp.8.5.2.Installer.exe'
            ProductId = ''
            Ensure = 'Present'
        }
    }
}

InstallNotepadPlusPlus
Start-DscConfiguration -Path ./InstallNotepadPlusPlus -Wait -Verbose

Sample Program

This script creates a configuration named EnsureFolder that makes sure the folder C:\MyFolder exists. Then it applies the configuration immediately.

PowerShell

Configuration EnsureFolder {
    Node 'localhost' {
        File MyFolder {
            DestinationPath = 'C:\MyFolder'
            Type = 'Directory'
            Ensure = 'Present'
        }
    }
}

EnsureFolder
Start-DscConfiguration -Path ./EnsureFolder -Wait -Verbose

Important Notes

DSC uses resources like File, Package, Service to define what you want on your machine.

You run the configuration function first to create files, then apply them with Start-DscConfiguration.

Use -Wait and -Verbose to see progress and wait until the setup finishes.

Summary

DSC helps keep your computer setup the way you want automatically.

You write a Configuration block with resources describing your desired setup.

Run the configuration and then apply it to enforce the desired state.