SAP-C02 Design for New Solutions Practice Question
A company is building a new microservices-based application on AWS using Amazon ECS with Fargate. The application has a frontend service, an order service, and a payment service. Services communicate synchronously via REST APIs. The company expects variable traffic and wants to ensure that failures in one service do not cascade to others. Which solution should a Solutions Architect recommend?
⚠ Common exam trap
SAP-C02 often tests the difference between high availability (multi-AZ, load balancing) and resilience patterns (circuit breakers, timeouts, retries) — candidates pick multi-AZ deployment thinking it prevents cascading failures, when it only addresses availability.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Implement retry logic with exponential backoff, circuit breakers, and timeouts in each service's client code.
For synchronous REST-based microservices on ECS Fargate with variable traffic and a requirement to prevent cascading failures, implementing retry logic with exponential backoff, circuit breakers, and timeouts in each service's client code is the correct approach. These patterns handle transient failures gracefully, prevent a failing service from overwhelming upstream callers, and ensure that a slow or unavailable dependency does not cause thread exhaustion or cascading timeouts.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use Amazon API Gateway in front of each service to throttle requests and protect against traffic spikes.
Why it's wrong here
API Gateway throttling limits request rates but does not isolate failing services; synchronous calls still propagate errors and timeouts downstream. It fits exposing and rate-limiting public APIs, whereas preventing cascading failure needs circuit breakers and retries with backoff in the calling services.
- ✓
Implement retry logic with exponential backoff, circuit breakers, and timeouts in each service's client code.
Why this is correct
Retries with exponential backoff, circuit breakers and timeouts directly contain synchronous REST failures, preventing a slow or failing payment service from exhausting order service threads and cascading. This satisfies the stem's isolation requirement, unlike infrastructure scaling alone, because resilience must live in the calling client code where the synchronous dependency is invoked.
- ✗
Convert all inter-service communication to asynchronous messaging using Amazon SQS or SNS.
Why it's wrong here
Asynchronous messaging decouples services but breaks the synchronous REST request/response contract the frontend depends on for immediate order and payment confirmations. SQS and SNS suit event fan-out, background jobs or buffering bursts, not blocking API calls awaiting a reply.
- ✗
Deploy multiple instances of each service across multiple Availability Zones and use an Application Load Balancer.
Why it's wrong here
Multi-AZ deployment and an Application Load Balancer provide availability and distribute traffic, yet synchronous REST calls still block and propagate failures between services. This suits stateless high-availability hosting; preventing cascading failure requires circuit breakers, timeouts and retries in the callers.
Visual reference
Go deeper
Related to this question
About these practice questions
One of 984 original SAP-C02 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This SAP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SAP-C02 exam.