Terraform Structure Demo

This is a sample structure using Terraform/Terragrunt to deal with creating, managing and destroying multiple environments. This is not meant to directly be a huge mono repo for DevOps but could also be broke up per project.

Getting Started

For MacOS Terminal or iTerm2

Consider instaling https://brew.sh

brew install asdf

asdf install

Will install terraform and terragrunt.

Demos in this repo

Setup

Set your S3 state bucket in root.hcl Set any common variables in common.hcl Set any and lower level settings in subdirectories terragrunt.hcl files.

cd terraform/environments/nonprod/dev/

• ecs-fargate-demo
• sqs-lambda-demo
• webapp-spa-demo
• shared/gitlab-ci AWS EKS Fargate Gitlab Runner
• shared/notifications/cw_alerts CloudWatch Alerts to Google Chat
• shared/rds/ AWS Aurora RDS Database

Terragrunt allows you to cd into these directories and either run one folder or use run-all at a parent level to capture all below it.

• terragrunt run-all validate
• terragrunt run-all plan
• terragrunt run-all apply
• terragrunt run-all destroy
• terragrunt validate-inputs

What are Terraform Modules

Terraform modules are reusable, self-contained configurations that encapsulate infrastructure components, allowing you to organize and manage your Terraform code more efficiently. They are structured with a main.tf for resources, variables.tf for inputs, outputs.tf for outputs, and optional files like providers.tf for provider configurations. Terraform's syntax, called HashiCorp Configuration Language (HCL), is a declarative language designed for defining infrastructure as code, using blocks, arguments, and expressions to describe desired resources and configurations.

Terraform has providers which interact with upstream APIs. As mentioned this is different than Cloudformation since Terraform is multi-cloud centric or Cloud-agnostic. This would support hybrid infrastructure/deployments. So you can even use pre-created modules supplied by the registry to fast track your design, community support, maintenance etc.

What is the Environments Folder?

The environments/ folder in Terragrunt acts as the stack orchestration layer, containing terragrunt.hcl files that define environment-specific configurations (e.g., dev, stage, prod). It manages inputs, backend settings, and dependencies, ensuring Terraform modules are deployed consistently across different environments.

Terragrunt why?

Using Terragrunt over plain Terraform provides several key advantages, particularly for managing complex infrastructure:

1. 📌 DRY (Don't Repeat Yourself)

   • Terragrunt allows you to reuse common configurations like backend settings, provider configurations, and variables across environments.
   • Reduces duplication and ensures consistency.

2. 🌍 Environment-Specific Configurations

   • Separate terragrunt.hcl files for each environment (e.g., dev, stage, prod).
   • Makes it easier to manage variations without duplicating module logic.

3. 🔗 Dependency Management

   • Define dependencies between modules to enforce correct execution order.
   • Ensures Terraform resources deploy in the right sequence when modules rely on each other.

4. ⚙️ Automation and Orchestration

   • Use terragrunt run-all to execute Terraform commands across multiple modules simultaneously.
   • Simplifies operations like apply, plan, and destroy for multi-module deployments.

5. ☁️ Simplified S3 State Management

   • Automates remote state storage (e.g., S3) and locking (e.g., DynamoDB).
   • Eliminates the need to manually configure backend settings in each module.

6. 🚨 Error Prevention & Safety Features

   • Use prevent_destroy to avoid accidental resource deletions.
   • Automates backend configuration, reducing misconfiguration risks.

7. 📦 Module Sourcing & Versioning – Easily pull Terraform modules from Git, S3, or local paths.

8. 🌐 Remote Execution Support – Enables running Terraform remotely, useful for CI/CD pipelines.

9. 📊 Dynamic Configuration with Locals – Avoids hardcoding by using locals in terragrunt.hcl.

10. 🔑 Flexible Secret Management – Supports secure handling of sensitive inputs.

11. 🚀 Multi-Environment Scalability – Helps manage multiple environments efficiently.

12. 👥 Improved Collaboration – Standardizes state management and enforces modular practices.