Terragrunt Frequently Asked Questions

We know there's a lot to learn about Terragrunt. Here are the frequently asked questions that users have asked and that you might find helpful!

Question	Answer
What is Terragrunt?	Terragrunt is a flexible orchestration tool that lets Infrastructure as Code written in OpenTofu/Terraform scale, adding tooling for keeping configurations DRY, managing dependencies, and running commands across many units at once.
How do I install Terragrunt?	Install Terragrunt with a package manager such as Homebrew, by downloading a prebuilt binary from the GitHub releases page, or by using the install script — then verify the install with `terragrunt --version`.
Why use Terragrunt instead of just OpenTofu/Terraform?	They have different jobs. OpenTofu/Terraform turn configuration into infrastructure. Terragrunt orchestrates many of those runs and absorbs the operational mess around them: segmented state, dependencies, targeted runs, retries, hooks, authentication, and caching.
What's the difference between a unit and a stack?	A unit is one piece of infrastructure with its own state, marked by a terragrunt.hcl file. A stack is a collection of units managed together, either as a directory tree of units or as a terragrunt.stack.hcl file that generates them.
Does Terragrunt create my state backend automatically?	Yes, if you ask it to. Pass --backend-bootstrap on a run, set TG_BACKEND_BOOTSTRAP, or run terragrunt backend bootstrap as its own step. Terragrunt does not create backend resources unless you opt in.
Is it safe to delete the .terragrunt-cache directory?	Yes. It is scratch space that Terragrunt recreates as needed, and it holds no state. If it keeps growing back, share provider downloads through a provider cache and let the Content Addressable Store deduplicate repository clones.
Terragrunt is running slowly. How do I speed it up?	Run fewer units with --filter, share provider downloads with the Provider Cache Server, and fetch dependency outputs from state instead of running output against every dependency. Measure first with OpenTelemetry traces.
How do I review plans across all my units?	Save the plans with --out-dir, and add --json-out-dir to get machine-readable copies you can filter with jq. The run summary tells you which units ran; the saved plans tell you what each one would do.
How do I get the docs for my version of Terragrunt?	Install the Terragrunt docs MCP server in your AI agent. It has the docs for every Terragrunt release from v0.80 onward, so the agent can answer for the version you run.