AWS Certified DevOps Engineer – Professional — Question 100

A DevOps engineer is designing a multi-Region disaster recovery strategy for an application. The application requires an RPO of 1 hour and requires an RTO of 4 hours. The application is deployed with an AWS CloudFormation template that creates an Application Load Balancer (ALB), Amazon EC2 instances in an Auto Scaling group and an Amazon RDS Multi-AZ DB instance with 20 GB of allocated storage. The AMI of the application instance does not contain data and has been copied to the destination Region.

Which combination of actions will meet the recovery objectives at the LOWEST cost? (Choose two.)

Answer options

• A. Launch an RDS DB instance in the failover Region. Use AWS Database Migration Service (AWS DMS) to configure ongoing replication from the source database.
• B. Upon failover, update the AWS CloudFormation stack in the failover Region to increase the desired number of instances in the Auto Scaling group. When the stack update is complete, change the DNS records to point to the failover Region's ALB.
• C. Upon failover, launch the AWS CloudFormation template in the failover Region with the DB snapshot ID as an input parameter. When the stack creation is complete, change the DNS records to point to the failover Region's ALB.
• D. Use AWS Backup to take a snapshot of the DB instance every hour and to copy the snapshot to the failover Region.
• E. Create an Amazon EventBridge (Amazon CloudWatch Events) event that invokes an AWS Lambda function to copy the RDS automated snapshot to the failover Region.

Correct answer: C, D

Explanation

Option C is correct because launching the CloudFormation template with the DB snapshot ID allows for quick restoration of the application with minimal costs. Option D is also valid as it ensures that backups are taken every hour and sent to the failover Region, meeting the RPO requirement. Options A and B may incur additional costs due to the use of AWS DMS and scaling actions, while option E does not directly address the RPO and RTO requirements effectively.