WhatIsACompositeResource

What Is a PowerShell DSC Composite Resource?

To understand what a PowerShell DSC composite resource is, we first need to understand what a PowerShell DSC resource is.

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What Is a PowerShell DSC Resource?

A PowerShell DSC (Desired State Configuration) resource is a packaged set of PowerShell files and supporting components that enables DSC to manage a specific type of system configuration.

Each DSC resource is designed to work with a related group of objects or settings, providing a standardized way to declare how those settings should be configured and enforced.

For example, the Registry DSC resource (which ships with Windows PowerShell) allows DSC configurations to manage Windows Registry keys and values declaratively. Rather than writing custom scripts, you describe the desired registry state in a configuration file, and DSC ensures that state is applied and maintained.

In short, DSC resources:

• Represent a single area of configuration (registry, files, services, firewall rules, etc.)
• Provide a declarative interface for managing that configuration
• Are consumed by DSC configurations rather than executed directly

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What Is a DSC Composite Resource?

A DSC composite resource builds on this concept by combining multiple DSC resources into a single, reusable unit.

Instead of managing one type of setting, a composite resource wraps several DSC resources together to represent a higher‑level configuration scenario. This allows you to capture best practices and repeatable patterns in one place.

For example, a composite resource might:

• Install required Windows features
• Create folders and registry settings
• Configure services and security options

All of these steps can then be exposed as a single logical resource with a simplified set of parameters.

Composite resources are not implemented as PowerShell classes or MOF schemas. Instead, they are written as PowerShell DSC configurations and packaged inside a module so they behave like first‑class DSC resources.

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Why Use Composite Resources?

Composite resources help you:

• Reduce duplication across DSC configurations
• Encapsulate complex logic behind a simple interface
• Standardize configuration patterns across teams and environments
• Make DSC configurations easier to read and maintain

They are especially useful in larger solutions—such as security baselines, application stacks, or compliance frameworks—where the same group of settings must be applied consistently.

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Summary

• A DSC resource manages a specific type of configuration
• A DSC composite resource combines multiple DSC resources into a single reusable unit
• Composite resources are written using PowerShell DSC configurations
• They enable cleaner, more maintainable, and standardized DSC implementations