Infrastructure as Code (IaC): Scenario-Based Questions

Terraform modules promote reusability, consistency, and scalability in cloud infrastructure provisioning. They allow teams to package infrastructure into versioned, composable units that can be reused across environments.

📦 What Are Modules?

• A module is a container for multiple resources that are used together (e.g., a VPC, ECS cluster, or RDS instance).
• Modules can be local (within the repo) or remote (e.g., Terraform Registry, Git).
• Modules accept input variables, produce outputs, and define reusable patterns.

⚙️ Usage Example

module "network" {
  source = "./modules/vpc"
  cidr_block = "10.0.0.0/16"
  environment = var.environment
}
        

🧱 Module Design Best Practices

• Write composable modules: one module per logical resource or service.
• Use variables.tf and outputs.tf to clearly define interfaces.
• Pin module versions in production to avoid drift.
• Provide defaults where safe, but allow overrides.

🚀 Benefits of Modules

• Faster onboarding and standardization.
• Reduced copy/paste in Terraform codebases.
• Easier environment duplication (e.g., dev, staging, prod).
• Encapsulation of complex logic (e.g., IAM roles, subnet layout).

🔧 Tooling and Registry

• Terraform Registry: Browse public modules for AWS, Azure, GCP.
• Terragrunt: Wrapper to manage remote state and DRY code across modules.
• Pre-commit hooks: Format and validate modules on every commit.

🚫 Common Pitfalls

• Using monolithic modules that become unmaintainable.
• Hardcoding values instead of passing inputs.
• Not isolating environments with separate backends or workspaces.

📌 Real-World Insight

Mature cloud teams use modules as foundational building blocks — versioned, audited, and distributed. Modules enable scalability and security by design, enforcing best practices across the stack.