🌍 Introduction to Terragrunt with a Simple Example

Terragrunt is a thin wrapper for Terraform that provides extra tools for keeping your configurations DRY (Don't Repeat Yourself), managing remote state, and working with multiple environments and modules more easily.

If you've worked with Terraform and struggled with:

• Copy-pasting the same backend config in multiple places
• Managing multiple environments like dev/staging/prod
• Handling dependencies between modules

Then Terragrunt can be your best friend!

🚀 Why Use Terragrunt?

• ✅ Centralized remote state management
• ✅ Keep configurations DRY with reusable components
• ✅ Manage multiple environments cleanly
• ✅ Handle module dependencies easily

🔧 How Terragrunt Works

Terragrunt uses a file named terragrunt.hcl to:

• Define where the Terraform module source lives
• Inject input variables dynamically
• Configure remote state settings
• Establish dependencies between modules

📦 A Simple Terragrunt Example

🎯 Goal:

Provision an AWS S3 bucket using a reusable Terraform module and Terragrunt.

🗂️ Directory Structure

.
├── terraform-modules/
│   └── s3/
│       └── main.tf
└── live/
    └── dev/
        └── s3/
            └── terragrunt.hcl

📁 terraform-modules/s3/main.tf

provider "aws" {
  region = var.region
}

resource "aws_s3_bucket" "this" {
  bucket = var.bucket_name
  acl    = "private"
}

variable "bucket_name" {}
variable "region" {}

📁 live/dev/s3/terragrunt.hcl

terraform {
  source = "../../../terraform-modules/s3"
}

inputs = {
  bucket_name = "my-dev-s3-bucket-123456"
  region      = "us-east-1"
}

▶️ Run the Code

From the live/dev/s3/ directory, run:

terragrunt init
terragrunt apply

This pulls the Terraform module, injects inputs, and applies it — all without duplicating configs.

📌 Summary

• Reduces configuration duplication
• Simplifies environment management
• Handles shared infrastructure modules cleanly

✅ Next Steps

• Try setting up remote state backend with generate blocks
• Use locals and dependencies blocks
• Explore environment-specific overrides with include

💡 Pro Tip: Keep terraform-modules in version control and reuse across all your live environments (dev, staging, prod).