Auto-init

Auto-Init is a feature of Terragrunt that makes it so that terragrunt init does not need to be called explicitly before other terragrunt commands.

When Auto-Init is enabled (the default), terragrunt will automatically call tofu init/terraform init before other commands (e.g. terragrunt plan) when terragrunt detects that any of the following are true:

• init has never been called.
• source needs to be downloaded.
• The .terragrunt-init-required file is in the downloaded module directory (.terragrunt-cache/aaa/bbb/modules/<module>).
• The modules or remote state used by a module have changed since the previous call to init.

As mentioned, extra_arguments can be configured to allow customization of the terraform init command.

Note that there might be cases where terragrunt does not properly detect that terraform init needs be called. In this case, OpenTofu/Terraform can fail. Running terragrunt init again in these circumstances can correct the issue.

Disabling Auto-Init

In some cases, it might be desirable to disable Auto-Init.

For example, you might want to specify a different -plugin-dir option to terraform init (and don’t want to have it set in extra_arguments).

To disable Auto-Init, use the --terragrunt-no-auto-init command line option or set the TERRAGRUNT_NO_AUTO_INIT environment variable to true.

Disabling Auto-Init means that you must explicitly call terragrunt init prior to any other Terragrunt commands for a particular configuration. If Auto-Init is disabled, and Terragrunt detects that init needs to be called, Terragrunt will throw an error.