You have been requested to use CloudFormation to maintain version control and achieve automation for the applications in your organization. Which of the following options is the best practice to keep everything agile and maintain multiple environments?

Answer options:

A.Create separate templates based on functionality and create nested stacks with CloudFormation.
B.Use CloudFormation custom resources to handle dependencies between stacks.
C.Create multiple templates in one CloudFormation stack.
D.Combine all resources into one template for version control and automation.

Answer – A
As your infrastructure grows, common patterns can emerge in which you declare the same components in each of your templates. You can separate out these common components and create dedicated templates for them. That way, you can mix and match different templates but use nested stacks to create a single, unified stack. Nested stacks are stacks that create other stacks. To create nested stacks, use the AWS::CloudFormation::Stackresource in your template to reference other templates.
For more information on Cloudformation best practices, please refer to the below link:
http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/best-practices.html