AWS Certified Solutions Architect – Associate (SAA-C02) — Question 539

A company has a legacy data processing application that runs on Amazon EC2 instances. Data is processed sequentially, but the order of results does not matter.
The application uses a monolithic architecture. The only way that the company can scale the application to meet increased demand is to increase the size of the instances.
The company's developers have decided to rewrite the application to use a microservices architecture on Amazon Elastic Container Service (Amazon ECS).
What should a solutions architect recommend for communication between the microservices?

Answer options

• A. Create an Amazon Simple Queue Service (Amazon SQS) queue. Add code to the data producers, and send data to the queue. Add code to the data consumers to process data from the queue.
• B. Create an Amazon Simple Notification Service (Amazon SNS) topic. Add code to the data producers, and publish notifications to the topic. Add code to the data consumers to subscribe to the topic.
• C. Create an AWS Lambda function to pass messages. Add code to the data producers to call the Lambda function with a data object. Add code to the data consumers to receive a data object that is passed from the Lambda function.
• D. Create an Amazon DynamoDB table. Enable DynamoDB Streams. Add code to the data producers to insert data into the table. Add code to the data consumers to use the DynamoDB Streams API to detect new table entries and retrieve the data.

Correct answer: A

Explanation

Amazon SQS is the ideal service for decoupling microservices, allowing the data producers and consumers to scale independently based on demand. Since the processing order of the results does not matter, a standard SQS queue provides a highly durable, scalable, and cost-effective message buffering solution. Using SNS, AWS Lambda, or DynamoDB Streams for simple point-to-point message queuing would introduce unnecessary complexity, cost, and architectural overhead.