The best answer is: Use AWS Backup to create a nightly backup plan. Add the EC2 instances as protected resources and configure cross-Region backup replication.

AWS Backup provides centralized, automated backup capabilities for a wide range of AWS services, including EC2 and EBS. By selecting EC2 instances as the backup resources, AWS Backup automatically captures both the root volume and any attached EBS data volumes, offering a complete and consistent backup. Furthermore, AWS Backup supports cross-Region replication, which allows you to store copies of backups in another AWS Region with minimal configuration and no custom scripting, meeting disaster recovery goals while minimizing operational effort.

The option Develop a Lambda function that triggers EBS snapshots for each volume and copies the snapshots to another AWS Region each night is functional but not the most efficient. It requires building, testing, and maintaining custom code to schedule and monitor snapshots, as well as manage Region-to-Region copying logic. This adds complexity and overhead compared to using a managed service like AWS Backup.

The option Configure AWS Backup to back up only the attached EBS volumes on a nightly basis and copy the backups to a second Region partially solves the problem. While it protects the data, it ignores the instance-level configuration, such as launch settings, AMI details, and network setup. As a result, full recovery in another Region would be more time-consuming and error-prone.

The option Use a Lambda function to take nightly EBS snapshots and replicate them to another Availability Zone for disaster recovery fails to meet the requirement for cross-Region recovery. Availability Zones within a Region share infrastructure to some extent, and storing backups in the same Region does not provide geographic redundancy in the event of a Region-wide disruption.

This question is valuable because it assesses your ability to choose scalable, low-maintenance backup strategies while accounting for disaster recovery requirements. Look for keywords like 'nightly backups,' 'multiple volumes,' and 'cross-Region recovery'these point to AWS Backup as the preferred managed solution.

The challenge in this question lies in differentiating between data backup and full instance protection. Many candidates incorrectly focus on EBS volumes alone without considering the instance configuration that must also be recoverable. Choosing the EC2 instance as a backup resource in AWS Backup handles this automatically.

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