aws cloudformation nested stacks

nested stacks allow for re-use of CloudFormation code for common use cases. This could be for sharing standard configurations for things like web servers or application servers.

Instead of copying the code each time, create a standard template for each common use case and reference that from another template.

CloudFormation Template Structure

An example CloudFormation template is below, showing the TemplateURL and Type for the nested stack that will be created.

Note: The TemplateURL is a file that must exist in an S3 bucket.

Resource:
Type: AWS::CloudFormation::Stack
Properties:
  NotificationARNs:
    - String
Parameters:
    AWS CloudFormation Stack Parameters
  Tags:
    - Resource Tag
  TemplateURL: https://s3.amazonaws.com/.../template.yml
  TimeoutInMinutes: Integer

Exam tips

• Code re-use using existing CloudFormation templates
• Useful for frequently used configurations for anything that gets created often