AWS Certified Solutions Architect – Professional — Question 849

A company runs a dynamic mission-critical web application that has an SLA of 99.99%. Global application users access the application 24/7. The application is currently hosted on premises and routinely fails to meet its SLA, especially when millions of users access the application concurrently. Remote users complain of latency.
How should this application be redesigned to be scalable and allow for automatic failover at the lowest cost?

Answer options

• A. Use Amazon Route 53 failover routing with geolocation-based routing. Host the website on automatically scaled Amazon EC2 instances behind an Application Load Balancer with an additional Application Load Balancer and EC2 instances for the application layer in each region. Use a Multi-AZ deployment with MySQL as the data layer.
• B. Use Amazon Route 53 round robin routing to distribute the load evenly to several regions with health checks. Host the website on automatically scaled Amazon ECS with AWS Fargate technology containers behind a Network Load Balancer, with an additional Network Load Balancer and Fargate containers for the application layer in each region. Use Amazon Aurora replicas for the data layer.
• C. Use Amazon Route 53 latency-based routing to route to the nearest region with health checks. Host the website in Amazon S3 in each region and use Amazon API Gateway with AWS Lambda for the application layer. Use Amazon DynamoDB global tables as the data layer with Amazon DynamoDB Accelerator (DAX) for caching.
• D. Use Amazon Route 53 geolocation-based routing. Host the website on automatically scaled AWS Fargate containers behind a Network Load Balancer with an additional Network Load Balancer and Fargate containers for the application layer in each region. Use Amazon Aurora Multi-Master for Aurora MySQL as the data layer.

Correct answer: C

Explanation

Option C is correct because a serverless architecture utilizing Amazon S3, Amazon API Gateway, and AWS Lambda provides automatic scaling and high availability at the lowest operational cost compared to managing container or EC2 instances. Amazon Route 53 latency-based routing ensures global users access the application with minimal latency, while Amazon DynamoDB global tables with DAX deliver seamless multi-region replication and fast caching. The other options involve maintaining idle load balancers and compute resources, which significantly increases costs and management overhead.