AWS Certified DevOps Engineer – Professional (DOP-C02) — Question 197

A company runs a web application that extends across multiple Availability Zones. The company uses an Application Load Balancer (ALB) for routing, AWS Fargate for the application, and Amazon Aurora for the application data. The company uses AWS CloudFormation templates to deploy the application. The company stores all Docker images in an Amazon Elastic Container Registry (Amazon ECR) repository in the same AWS account and AWS Region.

A DevOps engineer needs to establish a disaster recovery (DR) process in another Region. The solution must meet an RPO of 8 hours and an RTO of 2 hours. The company sometimes needs more than 2 hours to build the Docker images from the Dockerfile.

Which solution will meet the RTO and RPO requirements MOST cost-effectively?

Answer options

• A. Copy the CloudFormation templates and the Dockerfile to an Amazon S3 bucket in the DR Region. Use AWS Backup to configure automated Aurora cross-Region hourly snapshots. In case of DR, build the most recent Docker image and upload the Docker image to an ECR repository in the DR Region. Use the CloudFormation template that has the most recent Aurora snapshot and the Docker image from the ECR repository to launch a new CloudFormation stack in the DR Region. Update the application DNS records to point to the new ALB.
• B. Copy the CloudFormation templates to an Amazon S3 bucket in the DR Region. Configure Aurora automated backup Cross-Region Replication. Configure ECR Cross-Region Replication. In case of DR, use the CloudFormation template with the most recent Aurora snapshot and the Docker image from the local ECR repository to launch a new CloudFormation stack in the DR Region. Update the application DNS records to point to the new ALB.
• C. Copy the CloudFormation templates to an Amazon S3 bucket in the DR Region. Use Amazon EventBridge to schedule an AWS Lambda function to take an hourly snapshot of the Aurora database and of the most recent Docker image in the ECR repository. Copy the snapshot and the Docker image to the DR Region. In case of DR, use the CloudFormation template with the most recent Aurora snapshot and the Docker image from the local ECR repository to launch a new CloudFormation stack in the DR Region.
• D. Copy the CloudFormation templates to an Amazon S3 bucket in the DR Region. Deploy a second application CloudFormation stack in the DR Region. Reconfigure Aurora to be a global database. Update both CloudFormation stacks when a new application release in the current Region is needed. In case of DR, update the application DNS records to point to the new ALB.

Correct answer: B

Explanation

Option B is the most cost-effective solution as it utilizes Cross-Region Replication for both Aurora and ECR, ensuring that the latest backups and Docker images are readily available in the DR Region, thus meeting the RPO and RTO requirements efficiently. The other options either involve more complex setups, like manual image rebuilding or additional dependencies that could increase the recovery time or cost, making them less suitable for the scenario.