Terragrunt vs Atmos vs Terraspace: Best IaC Orchestration Tools 2026

When your infrastructure grows beyond a few modules, running Terraform or OpenTofu directly becomes unwieldy. You need to manage multiple environments, handle remote state backends, pass variables between modules, and enforce consistent workflows across teams. This is where IaC orchestration tools come in.

Terragrunt, Atmos, and Terraspace are three open-source tools designed to solve these problems at different scales. Each takes a distinct approach: Terragrunt wraps Terraform with DRY configuration, Atmos uses hierarchical YAML inheritance, and Terraspace provides a Rails-like framework for infrastructure code.

In this guide, we compare all three tools with real Docker Compose setups, configuration examples, and deployment instructions so you can pick the right orchestrator for your infrastructure.

What Are IaC Orchestration Tools?

Infrastructure as Code orchestration tools sit on top of Terraform or OpenTofu to solve common operational challenges:

• DRY configuration — avoid repeating backend, provider, and variable blocks across dozens of modules
• Environment management — cleanly separate dev, staging, and production configurations
• Dependency ordering — automatically deploy resources in the correct sequence
• State management — organize remote state files with consistent naming conventions
• Workflow standardization — enforce consistent apply, plan, and destroy patterns across teams

Without an orchestration layer, teams often end up with copy-pasted backend configurations, inconsistent environment setups, and fragile deployment scripts.

Terragrunt

Terragrunt (9,560+ stars) is the most widely adopted IaC orchestration tool. Created by Gruntwork, it wraps Terraform/OpenTofu and uses HCL configuration files to define backend settings, provider blocks, and variable inheritance.

Key Features

• terraform blocks — define backend S3/DynamoDB configuration once, inherit across all modules
• dependency blocks — automatically pass outputs between modules as input variables
• include blocks — inherit configuration from parent terragrunt.hcl files
• before_hook / after_hook — run custom commands before or after Terraform operations
• run-all command — execute Terraform commands across multiple modules in dependency order

Docker Compose Setup

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version: "3.8"
services:
  terragrunt:
    image: alpine/terragrunt:latest
    working_dir: /infra
    volumes:
      - ./infrastructure:/infra
      - ~/.aws:/root/.aws:ro
    environment:
      - AWS_REGION=us-east-1
      - TERRAGRUNT_LOG_LEVEL=info
    entrypoint: ["terragrunt"]
    command: ["run-all", "plan"]

Configuration Example

Root terragrunt.hcl:

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remote_state {
  backend = "s3"
  generate = {
    path      = "backend.tf"
    if_exists = "overwrite_terragrunt"
  }
  config = {
    bucket         = "my-terraform-state"
    key            = "${path_relative_to_include()}/terraform.tfstate"
    region         = "us-east-1"
    encrypt        = true
    dynamodb_table = "terraform-locks"
  }
}

generate "provider" {
  path      = "provider.tf"
  if_exists = "overwrite_terragrunt"
  contents  = <<EOF
provider "aws" {
  region = "us-east-1"
}
EOF
}

Child module terragrunt.hcl:

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include {
  path = find_in_parent_folders()
}

dependency "vpc" {
  config_path = "../vpc"
}

inputs = {
  vpc_id     = dependency.vpc.outputs.vpc_id
  subnet_ids = dependency.vpc.outputs.subnet_ids
}

Pros and Cons

Atmos

Atmos (1,290+ stars) by Cloud Posse takes a fundamentally different approach. Instead of wrapping Terraform with HCL, it uses YAML configuration files with deep hierarchical inheritance. It’s designed for organizations managing hundreds of components across dozens of accounts and regions.

Key Features

• YAML-based configuration — use familiar YAML with imports, mixins, and inheritance
• Hierarchical stack files — organize configuration by account, region, environment, and tenant
• Component catalog — define reusable infrastructure components with standardized inputs
• Native Terraform and Helmfile support — orchestrate both IaC and Helm releases
• Policy as Code — validate configurations with OPA/Rego before deployment

Docker Compose Setup

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version: "3.8"
services:
  atmos:
    image: cloudposse/atmos:latest
    working_dir: /infra
    volumes:
      - ./infrastructure:/infra
      - ~/.aws:/root/.aws:ro
    environment:
      - AWS_REGION=us-east-1
      - ATMOS_BASE_PATH=/infra
    entrypoint: ["atmos"]
    command: ["terraform", "plan", "vpc", "-s", "plat-ue2-dev"]

Configuration Example

atmos.yaml:

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components:
  terraform:
    base_path: "components/terraform"
    stacks:
      base_path: "stacks"
      included_paths:
        - "orgs/**/*"

Stack file stacks/orgs/acme/platform/ue2/dev.yaml:

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import:
  - orgs/acme/catalog/defaults
  - orgs/acme/platform/ue2/defaults

components:
  terraform:
    vpc:
      vars:
        cidr_block: "10.0.0.0/16"
        environment: "dev"
    eks:
      vars:
        cluster_name: "acme-platform-ue2-dev"
        vpc_id: "{{ $.components.terraform.vpc.vars.vpc_id }}"

Pros and Cons

Terraspace

Terraspace (715+ stars) takes a framework approach, inspired by Ruby on Rails conventions. It provides a project generator, module structure, and built-in CI/CD integration.

Key Features

• Rails-like conventions — generate projects with terraspace new project
• Built-in module system — organize reusable infrastructure as gems/packages
• Native CI/CD support — built-in GitHub Actions and GitLab CI templates
• Multiple cloud support — AWS, Azure, and GCP with consistent patterns
• Testing framework — write tests for infrastructure modules

Docker Compose Setup

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version: "3.8"
services:
  terraspace:
    image: ruby:3.3
    working_dir: /infra
    volumes:
      - ./infrastructure:/infra
      - ~/.aws:/root/.aws:ro
    environment:
      - AWS_REGION=us-east-1
      - TS_ENV=dev
    entrypoint: ["bash", "-c"]
    command: ["gem install terraspace && terraspace up demo -y"]

Configuration Example

Project structure:

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app/
├── stacks/
│   └── demo/
│       └── main.tf
├── modules/
│   └── vpc/
│       └── main.tf
└── config/
    └── terraspace.rb

config/terraspace.rb:

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Terraspace.configure do |config|
  config.logger.level = :info
  config.module.cache.options = { git: { depth: 1 } }
  config.test.framework = :rspec
end

app/stacks/demo/main.tf:

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module "vpc" {
  source = "../../modules/vpc"
  cidr   = TS.env("VPC_CIDR") || "10.0.0.0/16"
}

module "eks" {
  source = "../../modules/eks"
  vpc_id = module.vpc.vpc_id
}

Pros and Cons

Comparison Table

Choosing the Right IaC Orchestrator

Choose Terragrunt if: You want the most mature, widely-adopted tool with the largest community. It’s the safest choice for teams already using Terraform who need DRY configuration and dependency management without adopting a new paradigm.

Choose Atmos if: You manage infrastructure across multiple AWS accounts, regions, and environments. The hierarchical YAML inheritance model shines when you need to define base configurations and override them at various levels (account → region → environment → component).

Choose Terraspace if: You prefer convention over configuration and want a complete framework with built-in testing, CI/CD templates, and project generators. It’s ideal for teams that want structure and consistency from day one.

Why Self-Host Your IaC Orchestration?

Cloud-native IaC management platforms (Spacelift, env0, Scalr) offer convenient UIs and policy enforcement, but they come with trade-offs. Self-hosting your orchestration tool keeps your infrastructure configuration in your own repository, under your own control, with no vendor lock-in or per-user licensing fees.

Data sovereignty — your Terraform state files, variable values, and infrastructure plans never leave your build environment. This is critical for organizations with compliance requirements that prohibit sending infrastructure details to third-party services.

Cost predictability — self-hosted orchestration tools are open-source and free. Cloud platforms charge per user, per run, or per managed resource, which can scale unpredictably as your infrastructure grows.

Custom workflows — when you control the orchestration layer, you can customize every aspect of your deployment pipeline: custom hooks, pre-apply validation, post-apply notifications, and integration with internal tooling that cloud platforms don’t support.

For related infrastructure automation, see our Atlantis vs Digger vs Terrateam PR automation guide and our OpenTofu vs Terraform vs Pulumi IaC comparison.

FAQ

What is the difference between Terragrunt and Terraform?

Terragrunt is a wrapper around Terraform (and OpenTofu) that adds DRY configuration, dependency management, and remote state handling. You still write standard Terraform HCL for your resources — Terragrunt handles the operational overhead of running Terraform across multiple environments and modules.

Can Atmos work with OpenTofu?

Yes. Atmos orchestrates both Terraform and OpenTofu interchangeably. Since OpenTofu is a drop-in replacement for Terraform, Atmos commands work the same way regardless of which engine you use underneath.

Does Terraspace require Ruby knowledge?

Not necessarily. While Terraspace is built with Ruby, you primarily interact with it through CLI commands (terraspace up, terraspace plan). Your infrastructure code is still standard Terraform HCL. Ruby is only needed if you want to customize the configuration files or write custom tests.

Which tool is best for multi-environment setups?

All three support multi-environment workflows, but they differ in approach. Terragrunt uses directory structure and include blocks. Atmos uses hierarchical YAML stack files with deep inheritance. Terraspace uses the TS_ENV environment variable and directory conventions. Atmos is generally the most powerful for complex multi-account, multi-region setups.

Can I migrate from Terraform workspaces to an orchestration tool?

Yes. All three tools can work with existing Terraform code. Terragrunt is the easiest to adopt incrementally — you can add terragrunt.hcl files alongside existing modules without rewriting your Terraform code. Atmos and Terraspace require more upfront project restructuring but provide better long-term organization.

Do these tools support GitOps workflows?

Terragrunt works well with GitOps when combined with CI/CD runners like Atlantis or Digger. Atmos has built-in support for Git-based workflows with stack file versioning. Terraspace includes native GitHub Actions and GitLab CI templates. All three can be integrated into pull request-based infrastructure change workflows.