AWS Certified Solutions Architect – Professional — Question 543

What is a circular dependency in AWS CloudFormation?

Answer options

• A. When Nested Stacks depend on each other.
• B. When Resources form a Depend On loop.
• C. When a Template references an earlier version of itself.
• D. When a Template references a region, which references the original Template.

Correct answer: B

Explanation

A circular dependency occurs in AWS CloudFormation when resources are configured in a way that creates a closed loop of dependencies, such as Resource A depending on Resource B, which in turn depends on Resource A. Because CloudFormation cannot determine which resource to provision first, the deployment will fail. Other scenarios, such as referencing previous template versions or regional configurations, do not cause circular dependency errors.