Out Dir

import { Aside } from '@astrojs/starlight/components';

This flag only does anything when used with the --all flag for stack runs. It does nothing in single-unit runs.

To generate plan files for a single unit run, use the standard OpenTofu/Terraform -out flag like so:

terragrunt run -- plan -out=/tmp/tfplan

Specifies where Terragrunt writes native OpenTofu/Terraform plan files for each unit when running stack operations.

• Plans are written as tfplan.tfplan per unit.
• If the directory does not exist, Terragrunt creates it.
• Relative paths are resolved against the root working directory, and Terragrunt mirrors the unit path under this directory (e.g. <out-dir>/<relative-unit-path>/tfplan.tfplan).

--out-dir controls where Terragrunt reads and writes per-unit plan files, but it does not restrict which units run --all apply discovers. If your plan was scoped with --filter, you must reuse the same --filter on apply — otherwise Terragrunt will discover unfiltered units, fail to find their plan files in --out-dir, and error out.

See Saving OpenTofu/Terraform plan output for the full plan-then-apply pattern.

Examples:

# Save plans for all units under /tmp/tfplan
terragrunt run --all plan --out-dir /tmp/tfplan

# Apply using the previously generated plans (per-unit paths are inferred)
terragrunt run --all apply --out-dir /tmp/tfplan

See the Stacks docs for more usage examples.