Skip to main content
Terragrunt’s terraform_binary attribute enables you to specify a custom Terraform executable instead of relying on the system default. By pointing Terragrunt to a specific binary—either by name or full path—you can maintain consistent Terraform versions across multiple environments, projects, and CI/CD pipelines.
Before you begin, verify that the path to your custom Terraform binary is correct and that the file has execute permissions.
You can check permissions with ls -l /path/to/terraform.

​
Why Override the Terraform Binary?

For more on Terragrunt, see the official documentation.

​
Default Behavior (No terraform_binary)

When you omit terraform_binary, Terragrunt uses the Terraform executable found in your system PATH. Here’s a sample Terragrunt configuration without the override:
Run terragrunt version to confirm which Terraform version is used:

​
Overriding with terraform_binary

Imagine you’ve placed a beta build of Terraform (v1.9.0-beta) into your parent Terragrunt directory:
To force Terragrunt to use this specific executable, add the terraform_binary attribute:
Now check the Terragrunt version again:
Terragrunt will use Terraform v1.9.0-beta instead of the default in your PATH.
If the specified binary is not found or not executable, Terragrunt will fail to initialize. Always include the correct path and ensure execution rights.

​
Best Practices

  • Pin Terraform versions per project to minimize drift.
  • Store custom or beta executables in a consistent directory structure.
  • Use ${get_parent_terragrunt_dir()} or absolute paths to avoid ambiguity.
  • Incorporate version checks in your CI/CD pipelines to catch mismatches early.

Watch Video