Q91 — AWS DOP-C02 Ch.3

Question 91 of 100 | ← Chapter 3

A company runs an application using an Amazon Aurora Multi-AZ DB cluster compatible with MySQL. For disaster recovery purposes, a cross-Region read replica has been created. A DevOps engineer wants to automatically promote the replica so it becomes the primary database instance during a failure.

• A. Configure an Amazon Route 53 CNAME with a latency-based health check pointing to both the primary and replica endpoints. Subscribe Amazon CloudTrail to an Amazon SNS topic for Amazon RDS failure notifications and use that topic to invoke an AWS Lambda function that promotes the replica instance to primary.
• B. Create an Aurora custom endpoint pointing to the primary database instance. Configure the application to use this endpoint. Configure AWS CloudTrail to trigger an AWS Lambda function that promotes the replica instance and modifies the custom endpoint to point to the newly promoted instance.
• C. Create an AWS Lambda function that modifies the application’s AWS CloudFormation template to upgrade the replica, applies the template to update the stack, and reconfigures the application to point to the newly promoted instance. Create an Amazon CloudWatch alarm that invokes this Lambda function after a failure event.
• D. Store the Aurora endpoint in AWS Systems Manager Parameter Store. Create an Amazon EventBridge rule that detects database failures and invokes an AWS Lambda function to promote the replica instance and update the endpoint URL stored in AWS Systems Manager Parameter Store. Code the application to reload the endpoint from Parameter Store upon database connection failure. ✓

Correct Answer: D. Store the Aurora endpoint in AWS Systems Manager Parameter Store. Create an Amazon EventBridge rule that detects database failures and invokes an AWS Lambda function to promote the replica instance and update the endpoint URL stored in AWS Systems Manager Parameter Store. Code the application to reload the endpoint from Parameter Store upon database connection failure.

Explanation

This question tests implementation of automated cross-Region failover for Amazon Aurora. AWS Aurora documentation recommends using Amazon EventBridge to detect RDS failure events, triggering a Lambda function to promote the replica to an independent cluster, combined with Systems Manager Parameter Store to dynamically update the endpoint. Option D achieves fully automated DR: EventBridge detects failures in real time, Lambda promotes the replica, Parameter Store updates the endpoint, and the application reloads the new endpoint upon connection failure—ensuring seamless failover. Other options fall short in timeliness, endpoint management, or triggering mechanisms: Route 53 latency checks are not failure-aware, CloudTrail is not real-time, and CloudFormation updates are too slow.