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Module Types

WAM defines two module types (classifications), Resource Modules and Pattern Modules, that can be created, published, and consumed.

Resource Modules

Definition:
Resource Modules are self-contained Terraform modules designed to provision and manage specific Azure resources and their extensions in a consistent, repeatable manner.

Purpose:

  • Standardize the deployment of Azure resources.
  • Promote reuse and reduce duplication by encapsulating best practices for resource configuration.
  • Simplify lifecycle management by grouping related resources.

Key Characteristics:

  • Lifecycle Cohesion: All resources within a Resource Module share the same lifecycle (created, updated, or destroyed together).
  • Parent-Child Relationships: Modules often combine parent resources with their dependent child resources (e.g., an Azure Key Vault with its secrets, or a Storage Account with its containers and blobs).
  • Logical Grouping: Resources that are interdependent or commonly deployed together are logically grouped.
  • Parameterization: Expose input variables for customization while enforcing sensible defaults and validation.
  • Outputs: Provide outputs for integration with other modules or higher-level patterns.
  • Documentation: Include clear usage instructions, examples, and descriptions of inputs/outputs.

Availability:

  • Open Source: Resource Modules are published publicly, encouraging community collaboration, peer review, and reuse.
  • Versioned: Modules are versioned to ensure stability and traceability.

Example Use Cases:

  • Deploying a secure Azure Storage Account with default encryption and network rules.
  • Provisioning an Azure Key Vault with pre-configured access policies and secrets.

Pattern Modules

Definition:
Pattern Modules are higher-level Terraform modules that orchestrate multiple Resource Modules and additional components to deliver complete architectural patterns or solutions.

Purpose:

  • Enable rapid deployment of complex solutions by composing Resource Modules and other resources.
  • Capture and enforce organizational standards, business logic, and architectural best practices.
  • Abstract complexity and provide opinionated, ready-to-use patterns.

Key Characteristics:

  • Composition: Primarily built by combining multiple Resource Modules, but may also include scripts (e.g., PowerShell), configuration files (e.g., Dockerfiles), or other resources.
  • Business Logic: Often encapsulate proprietary logic, workflows, or compliance requirements.
  • Customization: Expose parameters for solution-level customization while hiding underlying complexity.
  • Integration: May integrate with external systems, CI/CD pipelines, or organizational processes.
  • Documentation: Provide detailed guidance on usage, customization, and integration points.

Availability:

  • Private: Pattern Modules are usually maintained privately within an organization, as they may contain sensitive or proprietary logic.
  • Controlled Access: Access is restricted to authorized teams or users.

Example Use Cases:

  • Deploying a secure web application pattern that includes networking, storage, compute, monitoring, and security controls.
  • Implementing a standardized landing zone for new projects, enforcing organizational policies and guardrails.

Summary Table

Aspect Resource Modules Pattern Modules
Scope Single resource or tightly coupled resources Multiple modules and resources (solution-level)
Purpose Standardize resource deployment Deliver architectural patterns and solutions
Availability Public, open source Private, organization-specific
Business Logic Minimal, focused on resource configuration May include significant business logic
Reusability High, across projects and teams High within organization, less across orgs
Examples Key Vault module, Storage Account module Secure web app pattern, landing zone pattern

When to Use Each Module Type

  • Resource Modules:
    Use when you need to deploy, manage, or reuse a specific Azure resource or a tightly coupled set of resources. Ideal for building blocks in your infrastructure-as-code strategy.

  • Pattern Modules:
    Use when you want to deploy a complete solution or architectural pattern that combines multiple resources, enforces standards, or implements business logic. Ideal for accelerating project setup and ensuring compliance.

Note:
In WAM documentation, the term “module” or “Well-Architected-Module” typically refers to Resource Modules unless otherwise specified.