AWS Certified DevOps Engineer – Professional (DOP-C02) — Question 353

A company has a search application that has a web interface. The company uses Amazon CloudFront, Application Load Balancers (ALBs), and Amazon EC2 instances in an Auto Scaling group with a desired capacity of 3. The company uses prebaked AMIs. The application starts in 1 minute. The application queries an Amazon OpenSearch Service cluster.

The application is deployed to multiple Availability Zones. Because of compliance requirements, the application needs to have a disaster recovery (DR) environment in a separate AWS Region. The company wants to minimize the ongoing cost of the DR environment and requires an RTO and an RPO of under 30 minutes. The company has created an ALB in the DR Region.

Which solution will meet these requirements?

Answer options

• A. Add the new ALB as an origin in the CloudFront distribution. Configure origin failover functionality. Copy the AMI to the DR Region. Create a launch template and an Auto Scaling group with a desired capacity of 0 in the DR Region. Create a new OpenSearch Service cluster in the DR Region. Set up cross-cluster replication for the cluster.
• B. Create a new CloudFront distribution in the DR Region and add the new ALB as an origin. Use Amazon Route 53 DNS for Regional failover. Copy the AMI to the DR Region. Create a launch template and an Auto Scaling group with a desired capacity of 0 in the DR Region. Reconfigure the OpenSearch Service cluster as a Multi-AZ with Standby deployment. Ensure that the standby nodes are in the DR Region.
• C. Create a new CloudFront distribution in the DR Region and add the new ALB as an origin. Use Amazon Route 53 DNS for Regional failover. Copy the AMI to the DR Region. Create a launch template and an Auto Scaling group with a desired capacity of 3 in the DR Region. Reconfigure the OpenSearch Service cluster as a Multi-AZ with Standby deployment. Ensure that the standby nodes are in the DR Region.
• D. Add the new ALB as an origin in the CloudFront distribution. Configure origin failover functionality. Copy the AMI to the DR Region. Create a launch template and an Auto Scaling group with a desired capacity of 3 in the DR Region. Create a new OpenSearch Service cluster in the DR Region. Set up cross-cluster replication for the cluster.

Correct answer: A

Explanation

Setting the Auto Scaling group desired capacity to 0 in the DR Region minimizes ongoing compute costs, which is highly cost-effective because the application can spin up within 1 minute, easily satisfying the 30-minute RTO. CloudFront origin failover seamlessly routes traffic to the secondary ALB without the overhead of managing a separate CloudFront distribution. Additionally, Amazon OpenSearch Service Multi-AZ deployments cannot span across different AWS Regions, making cross-cluster replication to a secondary region the correct method for meeting the RPO requirement.