AWS Certified Solutions Architect – Associate (SAA-C02) — Question 218

A company has a live chat application running on its on-premises servers that use WebSockets. The company wants to migrate the application to AWS.
Application traffic is inconsistent, and the company expects there to be more traffic with sharp spikes in the future.
The company wants a highly scalable solution with no server maintenance nor advanced capacity planning.
Which solution meets these requirements?

Answer options

• A. Use Amazon API Gateway and AWS Lambda with an Amazon DynamoDB table as the data store. Configure the DynamoDB table for provisioned capacity.
• B. Use Amazon API Gateway and AWS Lambda with an Amazon DynamoDB table as the data store. Configure the DynamoDB table for on-demand capacity.
• C. Run Amazon EC2 instances behind an Application Load Balancer in an Auto Scaling group with an Amazon DynamoDB table as the data store. Configure the DynamoDB table for on-demand capacity.
• D. Run Amazon EC2 instances behind a Network Load Balancer in an Auto Scaling group with an Amazon DynamoDB table as the data store. Configure the DynamoDB table for provisioned capacity.

Correct answer: B

Explanation

The correct answer is B because using Amazon API Gateway and AWS Lambda with an on-demand capacity DynamoDB table allows for automatic scaling and eliminates the need for server maintenance. Options A and D both involve provisioned capacity, which requires manual adjustments for scaling, while option C, despite using on-demand capacity, does not leverage serverless architecture, which the company desires.