What will CloudFormation do in this scenario?

A user has created a CloudFormation stack. The stack creates AWS services, such as EC2 instances, ELB, AutoScaling, and RDS. While creating the stack it created EC2, ELB and AutoScaling but failed to create RDS.

What will CloudFormation do in this scenario?
A .  Rollback all the changes and terminate all the created services
B .  It will wait for the user’s input about the error and correct the mistake after the input
C .  CloudFormation can never throw an error after launching a few services since it verifies all the steps before launching
D .  It will warn the user about the error and ask the user to manually create RDS

View Answer

Answer: A

Explanation:

AWS CloudFormation is an application management tool which provides application modeling, deployment, configuration, management and related activities. The AWS CloudFormation stack is a collection of AWS resources which are created and managed as a single unit when AWS CloudFormation instantiates a template. If any of the services fails to launch, CloudFormation will rollback all the changes and terminate or delete all the created services.

Reference: http://aws.amazon.com/cloudformation/faqs/