terragrunt

Initialize modules

$ terragrunt init

$ terragrunt plan

$ terragrunt apply

$ terragrunt destroy

$ terragrunt run-all apply

$ terragrunt run-all plan

$ terragrunt output

$ terragrunt graph-dependencies

terragrunt [init] [plan] [apply] [destroy] [run-all] [options]

terragrunt is a thin wrapper for Terraform that provides extra tools for keeping configurations DRY and managing multiple modules.
DRY configuration avoids repetition across environments. Common settings are defined once and inherited by modules.
Remote state configuration is centralized. Backend settings don't need repetition in every module.
Dependencies between modules are managed automatically. run-all executes commands across multiple modules in dependency order.
Before and after hooks run custom commands around Terraform operations. This enables validation, notifications, and cleanup.
Lock file management handles concurrent access. Multiple team members can work safely on shared infrastructure.

init

Initialize Terraform.

Show execution plan.

Apply changes.

Destroy infrastructure.

Show outputs.

Run command on all modules.

Show dependency graph.

Config file.

Working directory.

Module source override.

Non-interactive mode.

Parallel operations.

terragrunt.hcl

Module-level configuration file defining Terraform source, inputs, dependencies, and backend settings

Environment variable to override the default configuration file path

Environment variable to set the directory where Terragrunt downloads Terraform source code

Adds complexity over plain Terraform. Learning curve for configuration syntax. Some Terraform features need workarounds.

Terragrunt was created by Gruntwork around 2016 to address pain points in managing Terraform at scale. It's widely used for multi-environment, multi-account infrastructure management.

terraform(1), pulumi(1), aws(1)