Demo of Lab 4

Welcome to Lab 4. In this lesson, you’ll configure Terragrunt to deploy and manage an AWS VPC module. You have access to an AWS account—follow the steps below to set up credentials, initialize modules, enforce safeguards, and customize Terragrunt settings for a robust infrastructure workflow.

Keep your AWS credentials secure. You can retrieve them with:

show creds

Or log in via the provided link using your username and password. Consider opening a second terminal tab to streamline copy-and-paste.

1. Configure the VPC Module

In Terraform stack/VPC/terragrunt.hcl, reference the remote AWS VPC module (v5.8.1) from the Terraform Registry:

terraform {
  source  = "registry.terraform.io/terraform-aws-modules/vpc/aws"
  version = "5.8.1"
}

inputs = {
  name = "KodeKloud VPC"
  cidr = "10.64.0.0/16"
}

Initialize and review the plan:

cd "Terraform stack/VPC"
terragrunt init
terragrunt plan

You should see 4 to add. If everything checks out, continue to the next section.

2. Configure a Custom Terragrunt Cache

Terragrunt can cache downloaded modules locally to speed up repeated runs. Add a top-level download_dir in your root terragrunt.hcl:

download_dir = "/full/path/to/Terraform stack/.terragrunt_config"

terraform {
  source  = "registry.terraform.io/terraform-aws-modules/vpc/aws"
  version = "5.8.1"
}

remote_state {
  backend = "local"
  config  = {}
}

inputs = {
  name = "KodeKloud VPC"
  cidr = "10.64.0.0/16"
}

Re-initialize and verify the cache directory:

terragrunt init
ls "Terraform stack/.terragrunt_config"

Then plan and apply:

terragrunt plan
terragrunt apply

After confirming the apply, check the AWS Console under VPC to see your new VPC.

3. Prevent Accidental Destruction

Protect critical resources by adding a prevent_destroy lifecycle rule:

lifecycle {
  prevent_destroy = true
}

Re‐apply and test destruction:

terragrunt apply
terragrunt destroy

Terragrunt will refuse to destroy due to the prevent_destroy setting.

If you need to remove the resource later, you must first remove or comment out the prevent_destroy block.

4. Use a Specific IAM Role

All Terragrunt operations should assume the KodeKloudTerragruntRole role. Retrieve your AWS account ID:

aws sts get-caller-identity --output text --query Account

Then add the role ARN to terragrunt.hcl:

iam_role = "arn:aws:iam::<YOUR_ACCOUNT_ID>:role/KodeKloudTerragruntRole"

Verify the role is in use:

terragrunt plan

5. Specify a Custom Terraform Binary & Version

Use the Terraform 1.82 binary packaged in this stack:

terraform_binary             = "/full/path/to/Terraform stack/terraform_1.82/terraform"
terraform_version_constraint = "1.82"

Re‐run:

terragrunt init
terragrunt plan

6. Enforce a Terragrunt Version Constraint

Require Terragrunt in the >= 0.34.0, < 0.40.0 range:

terragrunt_version_constraint = ">= 0.34.0, < 0.40.0"

If you encounter a compatibility error (e.g., on version 0.58.8), update to include your version:

terragrunt_version_constraint = ">= 0.34.0, <= 0.59"

Then re‐plan:

terragrunt plan

7. Configure Retryable Errors

Handle transient network or locking issues by specifying retry patterns:

retryable_errors = [
  "Error locking state:.*",
  "no such host",
  "request timed out"
]

Run:

terragrunt plan
terragrunt apply

Terragrunt will retry on matching errors automatically.

Terragrunt Settings at a Glance

Setting	Purpose	Example
terraform.source	Module source	`"registry.terraform.io/.../vpc/aws"`
download_dir	Cache directory for modules	`"/path/to/.terragrunt_config"`
lifecycle.prevent_destroy	Prevent critical-resource deletion	`prevent_destroy = true`
iam_role	Specifies assumed IAM role	`"arn:aws:iam::123456789012:role/...TerragruntRole"`
terraform_binary	Custom Terraform CLI path	`"/path/to/terraform_1.82/terraform"`
terraform_version_constraint	Lock Terraform to a specific version	`"1.82"`
terragrunt_version_constraint	Lock Terragrunt to a version range	`">= 0.34.0, <= 0.59"`
retryable_errors	Patterns that trigger automatic retries	`["Error locking state:.*", "no such host"]`

Links and References

That completes Lab 4. Thank you for following along!

Introduction

Terragrunt - Good to Know Concepts & Ideas

Terragrunt Configuration

Terragrunt Commands

Terragrunt Functions

Terragrunt Blocks

Terragrunt Attributes

Managing Remote State with Terragrunt

Terragrunt Modules

Building our first AWS Demo with Terragrunt

Conclusion

Terragrunt - Basic Concepts

1. Configure the VPC Module

2. Configure a Custom Terragrunt Cache

3. Prevent Accidental Destruction

4. Use a Specific IAM Role

5. Specify a Custom Terraform Binary & Version

6. Enforce a Terragrunt Version Constraint

7. Configure Retryable Errors

Terragrunt Settings at a Glance

Links and References

Watch Video

Practice Lab

​1. Configure the VPC Module

​2. Configure a Custom Terragrunt Cache

​3. Prevent Accidental Destruction

​4. Use a Specific IAM Role

​5. Specify a Custom Terraform Binary & Version

​6. Enforce a Terragrunt Version Constraint

​7. Configure Retryable Errors

​Terragrunt Settings at a Glance

​Links and References

Watch Video

Practice Lab

1. Configure the VPC Module

2. Configure a Custom Terragrunt Cache

3. Prevent Accidental Destruction

4. Use a Specific IAM Role

5. Specify a Custom Terraform Binary & Version

6. Enforce a Terragrunt Version Constraint

7. Configure Retryable Errors

Terragrunt Settings at a Glance

Links and References