A company has one large template that creates a network tier, a database tier, and an application tier. The network portion must be reusable by other teams and updated on its own. Which CloudFormation feature supports this?
Show answer and explanation
Answer: A
A parent template can declare an AWS::CloudFormation::Stack resource that points at a separate template in S3, making that child stack a resource of the parent. The network template can then be versioned and referenced by several parents.
The child stays tied to its parent: stack operations on the root flow down, and the child cannot be deleted independently while the parent still references it.
Why the other options are wrong
- B. Stack policies guard named resources against updates during stack operations and do nothing for template reuse.
- C. Change sets preview the effect of a pending update and do not modularize templates.
- D. StackSets deploy one template to many accounts and Regions; they do not compose reusable pieces inside a single stack.
Exam tip. Nested stacks reuse templates; StackSets replicate a stack across accounts.