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CloudFormation Region Resolution and Static Dry-Run

Detail for the CloudFormation skill.

Region resolution

CloudFormation API calls need an AWS region, resolved most-specific-wins:

  1. settings.aws_cloudformation.region on the component
  2. The active identity's region
  3. The AWS SDK's default credential/region chain (AWS_REGION, shared config)

A component env that sets AWS_REGION/AWS_DEFAULT_REGION does not change the region; Atmos warns when it differs from the resolved region and points to settings.aws_cloudformation.region.

There is no per-component account override outside StackSets — the account is always the active identity's account.

Static dry-run

--dry-run defers YAML functions, Go templates, source downloads, authentication and hooks, including with render and bulk/affected selection. It validates known static fields and reports execution-dependent checks as deferred. Use a normal render to inspect a provisioned template. Bulk deletion reverses dependency order so consumers can still resolve producer outputs. Named changeset execution enables configured termination protection after successful completion, just as apply does; false never disables existing protection.