Stacks

import { Aside } from '@astrojs/starlight/components';

A stack in Terragrunt is a collection of related units that can be managed together. Stacks provide a way to:

• Deploy multiple infrastructure components with a single command
• Manage dependencies between units automatically
• Control the blast radius of changes
• Organize infrastructure into logical groups

Terragrunt supports two approaches to defining stacks:

1. Implicit Stacks: Created by organizing units in a directory structure.
2. Explicit Stacks: Defined using terragrunt.stack.hcl files.

Choosing Between Implicit and Explicit Stacks

Use Implicit Stacks When:

• You have a small number of units.
• Each unit is unique and not repeated across environments.
• You don't mind a high file count.
• You're just getting started with Terragrunt.
• You need maximum explicitness and transparency.

Use Explicit Stacks When:

• You have multiple environments (dev, staging, prod).
• You want to reuse collections of related infrastructure patterns.
• You have many similar units that differ only in values.
• You want to version collections of infrastructure patterns.
• You're building infrastructure catalogs or templates.

<Aside type="tip"> Start with implicit stacks to get familiar with the concept, then gradually introduce explicit stacks for reusable patterns as your infrastructure grows. </Aside>

Examples

For detailed examples, see the Gruntwork Terragrunt Infrastructure Catalog Stack Examples. These have full-featured examples of stacks that deploy real, stateful infrastructure in an AWS account.