AWS Certified Solutions Architect – Associate (SAA-C03) — Question 601

A development team is creating an event-based application that uses AWS Lambda functions. Events will be generated when files are added to an Amazon S3 bucket. The development team currently has Amazon Simple Notification Service (Amazon SNS) configured as the event target from Amazon S3.

What should a solutions architect do to process the events from Amazon S3 in a scalable way?

Answer options

• A. Create an SNS subscription that processes the event in Amazon Elastic Container Service (Amazon ECS) before the event runs in Lambda.
• B. Create an SNS subscription that processes the event in Amazon Elastic Kubernetes Service (Amazon EKS) before the event runs in Lambda
• C. Create an SNS subscription that sends the event to Amazon Simple Queue Service (Amazon SQS). Configure the SOS queue to trigger a Lambda function.
• D. Create an SNS subscription that sends the event to AWS Server Migration Service (AWS SMS). Configure the Lambda function to poll from the SMS event.

Correct answer: C

Explanation

Subscribing an Amazon SQS queue to the Amazon SNS topic implements the fan-out pattern, which buffers messages and allows AWS Lambda to scale out and process events reliably without dropping them. Options A and B introduce unnecessary overhead and complexity by routing events through container orchestrators like Amazon ECS or Amazon EKS before reaching Lambda. Option D is incorrect because AWS Server Migration Service (AWS SMS) is a tool for migrating physical and virtual servers to AWS and has no role in application event messaging.