Modules and Projects

In Infrastructure as Code (IaC), organization is key to maintaining scalable and manageable systems. Think of building infrastructure like constructing buildings - you need both basic building materials (modules) and blueprints for complete structures (projects).

The Construction Analogy

Imagine building with LEGO® bricks:

• Modules are like the individual LEGO® bricks - standardized, reusable pieces that serve specific purposes
• Projects are like the instruction manuals for complete LEGO® sets - they define how to combine those bricks into a functional structure

Modules (The Bricks)

A module is a reusable, self-contained unit of infrastructure code that performs a specific task or creates a specific resource. Like standardized bricks, modules are:

• Reusable: Can be used in multiple projects
• Self-contained: Have clear inputs (variables) and outputs
• Single-purpose: Focus on one specific infrastructure component
• Versioned: Stored in a registry for consistent use

When to Create a Module

Create a module when you have infrastructure code that:

• Will be reused across multiple projects
• Represents a clear, single-purpose component
• Has well-defined inputs and outputs
• Provides value as a standalone unit

For example, a module might handle:

• VPC creation with standard networking
• EKS node group configuration
• Standard S3 bucket setups
• RDS instance deployment

Projects (The Houses)

A project is a complete infrastructure solution that combines modules to achieve a specific goal. Like a house blueprint, projects:

• Define the overall architecture
• Specify how modules work together
• Handle environment-specific configurations
• Manage dependencies between components

The Environment Project

A special type of project is the “environment” project, which:

• Creates the foundational infrastructure
• Sets up shared resources
• Establishes networking boundaries
• Serves as a dependency for other projects

When to Create a Project

Create a new project when you need to:

• Deploy a complete infrastructure solution
• Combine multiple modules for a specific purpose
• Manage environment-specific configurations
• Create isolated infrastructure components

For example, a project might be:

• “My AWS EKS Cluster” - combining networking, cluster, and node group modules
• “Data Platform” - combining storage, compute, and security modules
• “Web Application” - combining application, database, and caching modules

Evolution and Maintenance

As your infrastructure grows:

• Modules should remain stable and focused
• Projects adapt to changing requirements
• New modules are added to the registry
• Existing projects are updated to use new module versions

Remember: Good organization of modules and projects leads to:

• Easier maintenance
• Better reusability
• Clearer documentation
• Simplified collaboration