Terragrunt for DRY configurations in Terraform - Mini Project: Build & Apply

Terragrunt for DRY configurations

📖 Scenario: You are managing infrastructure for a company that has multiple environments: development, staging, and production. Each environment uses similar Terraform modules but with different settings. To avoid repeating the same configuration in each environment, you want to use Terragrunt to keep your Terraform code DRY (Don't Repeat Yourself).

🎯 Goal: Build a Terragrunt configuration that uses a common Terraform module with shared settings, and environment-specific overrides, to manage infrastructure for three environments without repeating code.

📋 What You'll Learn

Create a Terragrunt root configuration with common settings

Create environment-specific Terragrunt configurations that inherit from the root

Use the terraform block to specify the source module

Use the inputs block to pass variables to the Terraform module

Demonstrate how to keep configurations DRY using Terragrunt's include feature

💡 Why This Matters

🌍 Real World

Companies often manage multiple environments with similar infrastructure. Terragrunt helps avoid repeating code by sharing common configuration and allowing environment-specific overrides.

💼 Career

Understanding Terragrunt is valuable for cloud engineers and DevOps professionals who manage infrastructure as code efficiently and maintainably.

1

Create the root Terragrunt configuration

Create a file named terragrunt.hcl in the root folder with a terraform block that sets the source to git::https://github.com/example/infrastructure-modules.git//network. Also, add an inputs block with region = "us-east-1" and environment = "root".

Terraform

# Your code here

Need a hint?

Use the terraform block to specify the module source URL. Then add an inputs block with the required variables.

2

Create the development environment Terragrunt configuration

Create a file named dev/terragrunt.hcl that uses the include block to inherit from the root terragrunt.hcl. Override the inputs block to set environment = "dev" and add instance_count = 1.

Terraform

terraform {
  source = "git::https://github.com/example/infrastructure-modules.git//network"
}

inputs = {
  region      = "us-east-1"
  environment = "root"
}

# Your code here

Need a hint?

Use the include block with find_in_parent_folders() to inherit root settings. Then override inputs with environment-specific values.

3

Create the staging environment Terragrunt configuration

Create a file named staging/terragrunt.hcl that includes the root configuration using include. Override the inputs block to set environment = "staging" and instance_count = 2.

Terraform

terraform {
  source = "git::https://github.com/example/infrastructure-modules.git//network"
}

inputs = {
  region      = "us-east-1"
  environment = "root"
}

include {
  path = find_in_parent_folders()
}

inputs = {
  environment    = "dev"
  instance_count = 1
}

# Your code here

Need a hint?

Similar to the dev environment, use include and override inputs for staging.

4

Create the production environment Terragrunt configuration

Create a file named prod/terragrunt.hcl that includes the root configuration using include. Override the inputs block to set environment = "prod" and instance_count = 3. This completes the DRY Terragrunt setup for all environments.

Terraform

terraform {
  source = "git::https://github.com/example/infrastructure-modules.git//network"
}

inputs = {
  region      = "us-east-1"
  environment = "root"
}

include {
  path = find_in_parent_folders()
}

inputs = {
  environment    = "dev"
  instance_count = 1
}

// staging/terragrunt.hcl
include {
  path = find_in_parent_folders()
}

inputs = {
  environment    = "staging"
  instance_count = 2
}

# Your code here

Need a hint?

Follow the same pattern as previous environments to complete the production configuration.