Last week, a developer changed the name of an Amazon PostgreSQL RDS database instance from “employeeDatabase” to “employee_DB” and then updated the CloudFormation stack.

Answer options:

A.Use Change Sets to check how your changes might impact your running resources, especially for critical resources such as RDS. Change Sets is also able to tell if the stack update is successful or not so that it can greatly help on the CloudFormation resources management.
B.Make sure that all RDSs are protected in the DeletePolicy by using the “Keep” keyword, then they are protected from deletion when stack update is happening. You could then make a snapshot of the RDS to backup data to use it in the future.
C.Use a data pipeline to copy the data from RDS to S3 for backup before executing any stack update. Using this way, the RDS instance data is saved in a suitable manner.
D.Generate a change set to see if the change will cause your database to be replaced. Do the necessary backup before executing the Change Set. If everything is good, execute the Change Set and use the CloudFormation console to monitor.

Correct Answer – D
Change Sets is typically used to understand if a stack update has been done successfully so that some unexpected consequences can be avoided.
For more information on how to use Change Sets, please refer to the link below:
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-changesets.html
Option A is incorrect: It is proper to use Change Sets. However “Change Sets don`t indicate whether AWS CloudFormation will successfully update a stack”.
This is stated in https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-changesets.html.
Change Sets is NOT able to tell whether the stack update is successful or not.
Option B is incorrect: Although DeletePolicy should be good to use, the keyword for RDS instance should be “Retain” rather than “Keep”.
To prevent deletion or updates to resources in a CloudFormation stack, you can:
Set DeletionPolicy attributes to retain certain resources when the stack is deleted.
Enable Termination Protection to prevent the stack from being deleted.
Use a stack policy to prevent update actions (modify, replace, or delete) to resources in the stack.
Apply IAM policies to allow only certain users to delete or update resources.
Option C is incorrect: Data pipeline is not a good use case for CloudFormation stack to keep resources.