Q85 — AWS DOP-C02 Ch.3

Question 85 of 100 | ← Chapter 3

A DevOps engineer manages an application for a video streaming company that handles video files. The application runs on Amazon EC2 instances behind an Elastic Load Balancing (ELB) Application Load Balancer. These instances run in an Auto Scaling group spanning multiple Availability Zones. Data is stored in an Amazon RDS PostgreSQL Multi-AZ DB instance, and video files are stored in an Amazon S3 bucket. Typically, 50 GB of new video content is added daily to the S3 bucket. The engineer wants to implement a multi-Region disaster recovery plan with minimal data loss and shortest possible recovery time. The current application infrastructure is already defined using AWS CloudFormation. Which deployment option should the engineer choose to meet the application’s uptime and recovery objectives?

• A. Launch the application from a CloudFormation template in a secondary Region with Auto Scaling group capacity set to 1. Create an Amazon RDS read replica in the secondary Region. Enable cross-Region replication between the original S3 bucket and a new S3 bucket in the secondary Region. For failover, promote the read replica to primary and update the CloudFormation stack to increase Auto Scaling group capacity. ✓
• B. Launch the application from a CloudFormation template in a secondary Region with Auto Scaling group capacity set to 1. Create a scheduled task to take daily cross-Region Amazon RDS snapshots to the secondary Region. Enable cross-Region replication between the original S3 bucket and Amazon Glacier in the secondary Region. During disaster recovery, launch a new application stack in the secondary Region and restore the database from the latest snapshot.
• C. Launch the application from a CloudFormation template in a secondary Region with Auto Scaling group capacity set to 1. Use Amazon CloudWatch Events to schedule nightly tasks to take database snapshots, copy them to the secondary Region, and replace the database instance in the secondary Region with the snapshot. Enable cross-Region replication between the original S3 bucket and a new S3 bucket in the secondary Region. For failover, increase Auto Scaling group capacity.
• D. Use Amazon CloudWatch Events to schedule nightly tasks to take database snapshots and copy them to the secondary Region. Create an AWS Lambda function triggered by S3 event notifications to replicate each object to a new S3 bucket in the secondary Region. In the secondary Region, launch the application from the CloudFormation template and restore the database from the latest snapshot.

Correct Answer: A. Launch the application from a CloudFormation template in a secondary Region with Auto Scaling group capacity set to 1. Create an Amazon RDS read replica in the secondary Region. Enable cross-Region replication between the original S3 bucket and a new S3 bucket in the secondary Region. For failover, promote the read replica to primary and update the CloudFormation stack to increase Auto Scaling group capacity.

Explanation

Option A is optimal. It enables rapid failover by launching a minimally scaled application in the secondary Region and maintaining an RDS read replica there. Cross-Region S3 replication ensures no video data loss, and promoting the read replica to primary provides near-instant database recovery. This satisfies both minimal data loss and shortest recovery time objectives. Other options introduce unacceptable delays (e.g., snapshot-based restores), data durability issues (e.g., Glacier replication), or lack real-time consistency guarantees.