Terragrunt

Terragrunt is an open-source wrapper around Terraform and OpenTofu that organizations use to help keep code DRY. If used in Scalr, Scalr will use all of the Terragrunt commands on top of Terraform or OpenTofu, depending on the pipeline settings.

Configuration

To add Terragrunt, go to the account scope in Scalr, the integrations page, and select Terragrunt. Once selected, it can be enabled for the entire account for use:

There are optional checks that can be enabled for all workspaces that are using Terragrunt:

• terragrunt hclvalidate - Finds all hcl files from the config stack and validates them.
• terragrunt hclfmt - Recursively find hcl files and rewrite them into a canonical format with the check mode enabled.
• terragrunt validate-inputs - Checks if the Terragrunt configured inputs align with the Terraform defined variables.

It will be available to all workspaces once the changes are saved.

Using Terragrunt

End users have the choice to enable Terragrunt at the workspace when creating a workspace or by updating the pipeline afterward. When creating a workspace, users are prompted to select the IaC platform (Terraform or OpenTofu and whether or not it should run with Terragrunt:

If Terragrunt is being added after a workspace has already been created, it can be added in the pipeline settings:

Users will see in the run that Terragrunt is being used to execute the commands:

Run-All

The run-all feature in Terragrunt is a powerful command that allows users to orchestrate Terraform or OpenTofu commands across multiple modules in a single execution. It simplifies managing complex infrastructure with multiple dependencies by handling the execution order and dependencies automatically.

When using run-all with Scalr:

• Terragrunt will automatically execute the run-all commands across all relevant modules defined in the workspace.
• Users can observe the execution logs in the Scalr interface, showing the commands being run for each module.
• Dependency resolution ensures a smooth workflow even in complex stacks.

The Terragrunt run-all option in Scalr is available in environments where the Scalr backend is disabled. To use run-all, ensure backend configurations are managed in your terragrunt.hcl files and Scalr's backend is disabled for the environment.

While creating or editing workspace in the Pipeline Setting section:

• Enable Use Terragrunt toggle
• Select Terragrunt version (0.69.1 or higher)
• Set Execute run-all commands on multiple units at once check-box to true

To use run-all, the workspace must use Terragrunt version 0.69.1 or greater. At this point, run-all workspaces do not support the following (they will be supported in the future):

• Structured plan output
• Cost estimation
• Policy checks
• Downloading of plan JSON
• Outputs