DVA-C02 Question 21
Select 2A development team is designing an e-commerce application on AWS. The system needs to process customer orders and decouple the order placement process from the order fulfillment process to improve scalability and fault tolerance. Which of the following AWS architectural choices aligns with a loosely coupled design?
- A
Use Amazon SQS to queue orders and process them asynchronously with an application running on Amazon EC2.
- B
Invoke an AWS Lambda function directly from the front-end application to process and fulfill orders in real-time.
- C
Use Amazon SNS to publish order messages and have multiple subscribers process the messages independently.
- D
Store customer orders in a tightly coupled relational database on Amazon RDS and process orders synchronously in the same application flow.
Show answer and explanation
Correct answers: A, C
Explanation
In a loosely coupled architecture, components operate independently, allowing for improved scalability, fault tolerance, and flexibility. Amazon SQS and Amazon SNS are services designed to decouple components by enabling asynchronous communication, while directly invoking functions or synchronously relying on a shared resource (like a tightly coupled database) leads to a tightly coupled system.
- A. Correct.
Using Amazon SQS to queue orders and process them asynchronously separates the order placement and order fulfillment processes, making the system loosely coupled. This improves scalability and fault tolerance.
- B. Incorrect.
Invoking an AWS Lambda function directly from the front-end application creates a tightly coupled system because the function is directly dependent on the front-end invocation. This does not align with a loosely coupled design.
- C. Correct.
Using Amazon SNS to publish order messages and having multiple subscribers independently process the messages promotes loose coupling by enabling asynchronous communication between components.
- D. Incorrect.
Storing orders in a tightly coupled relational database and processing them synchronously does not decouple the order placement and fulfillment processes, making it a tightly coupled design.