AWS Certified Developer – Associate (DVA-C02) — Question 355

A company uses AWS CloudFormation templates to manage infrastructure for a public-facing application in its development, pre-production, and production environments. The company needs to scale for increasing customer demand. A developer must upgrade the Amazon RDS DB instance type to a larger instance.

The developer deploys an update to the CloudFormation stack with the instance size change in the pre-production environment. The developer notices that the stack is in an UPDATE_ROLLBACK_FAILED slate in CloudFormation.

Which option is the cause of this issue?

Answer options

• A. The new instance type specified in the CloudFormation template is invalid
• B. The database was deleted or modified manually outside of the CloudFormation stack
• C. There is a syntax error in the CloudFormation template
• D. The developer has insufficient IAM permissions to provision an instance of the specified type

Correct answer: B

Explanation

The UPDATE_ROLLBACK_FAILED state occurs when AWS CloudFormation is unable to revert resources to their previous states during a rollback process, which typically happens if resources have been manually modified or deleted outside of CloudFormation. If the database was deleted or altered out-of-band, CloudFormation cannot find the original resource to restore, resulting in a rollback failure. Syntax errors, invalid instance types, or insufficient IAM permissions would cause the initial update to fail and trigger a rollback, but they would not cause the rollback itself to fail.