Which solution will meet these requirements in the MOST operationally efficient way?
Create Amazon Machine Images (AMIs) to back up the EC2 instances. Copy the AMIs to a secondary AWS Region. Automate infrastructure deployment in the secondary Region by using AWS Lambda and custom scripts.
Create Amazon Machine Images (AMIs) to back up the EC2 instances. Copy the AMIs to a secondary AWS Region. Automate infrastructure deployment in the secondary Region by using AWS CloudFormation.
Launch EC2 instances in a secondary AWS Region. Keep the EC2 instances in the secondary Region active at all times.
Launch EC2 instances in a secondary Availability Zone. Keep the EC2 instances in the secondary Availability Zone active at all times.
Explanations:
While creating AMIs and copying them to a secondary Region is a good backup strategy, using AWS Lambda with custom scripts for automation adds complexity and may not ensure efficient deployment or meet the RTO requirement effectively.
Creating AMIs and using AWS CloudFormation for automation in the secondary Region provides a systematic and efficient way to deploy the necessary infrastructure, ensuring quick recovery within the specified RTO, while minimizing resource use during normal operations.
Keeping EC2 instances active in a secondary Region at all times is resource-intensive and costly. This approach does not align with the requirement to use the fewest possible resources during normal operations, despite potentially meeting the RTO.
Similar to option C, keeping EC2 instances active in a secondary Availability Zone is also resource-intensive and unnecessary for disaster recovery. It does not provide the most efficient use of resources while still meeting the RTO.
I figure that the answer is:
Create Amazon Machine Images (AMIs) to back up the EC2 instances. Copy the AMIs to a secondary AWS Region. Automate infrastructure deployment in the secondary Region by using AWS CloudFormation.