SAA-C03 Design Resilient Architectures Practice Question
A warehouse integration service must process every event at least once, but duplicate processing is acceptable if the consumer handles idempotency. Which eventing approach is most suitable? The design must avoid adding custom operational scripts.
⚠ Common exam trap
Many exam-takers choose UDP (Option C) thinking it is lightweight and fast, but they overlook its lack of delivery guarantees, which fails the 'process every event at least once' requirement.
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
✓
Use Amazon SQS standard queue and design consumers to be idempotent
Amazon SQS standard queues provide at-least-once delivery, ensuring every event is processed at least once, with the possibility of duplicates. Designing consumers to be idempotent handles duplicates without requiring custom scripts, aligning with the requirement to avoid operational overhead. This approach is serverless, scalable, and fits the warehouse integration use case.
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 CloudFront signed URLs
Why it's wrong here
CloudFront signed URLs are an access-control mechanism that grants temporary permission to retrieve content from a CloudFront distribution. They do not provide event delivery, queueing, or guaranteed processing semantics. The service relies on HTTP GET requests and cannot ensure at-least-once delivery or transparently recover from consumer failures, making it fundamentally unsuitable as a durable integration pipeline.
- ✓
Use Amazon SQS standard queue and design consumers to be idempotent
Why this is correct
An Amazon SQS standard queue provides high-throughput, distributed, and durable messaging with at-least-once delivery semantics. Because duplicates can occur due to the distributed architecture, consumers must be idempotent to correctly handle repeated messages without side effects. The queue also decouples event producers from workers, automatically buffering events and allowing independent scaling of processing capacity, which satisfies the requirement to process every event reliably.
- ✗
Use UDP messages sent directly to workers
Why it's wrong here
UDP is a connectionless, best-effort transport protocol that provides no reliability guarantees, acknowledgments, ordering, or duplicate detection. Messages can be silently lost during network congestion or worker restarts, and there is no built-in retry mechanism or durable buffering. Direct UDP delivery to workers also tightly couples producers to specific instances, preventing robust scaling and making it impossible to guarantee every event is processed at least once.
- ✗
Use an in-memory queue on one EC2 instance
Why it's wrong here
An in-memory queue running on a single EC2 instance is both non-durable and not highly available. If the instance fails, restarts, or the application crashes, all queued events are lost with no recovery mechanism. It also creates a single point of failure and a scalability bottleneck, so it cannot meet the integration service's requirement to process every event reliably at scale.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAA-C03 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 SAA-C03 exam.