SAA-C03 Design Resilient Architectures Practice Question
A patient portal receives bursts of orders that sometimes overwhelm a downstream fulfilment service. The architecture must absorb spikes and retry processing without losing requests. Which service should be placed between the web tier and fulfilment workers? The design must avoid adding custom operational scripts.
⚠ Common exam trap
Test-takers frequently confuse decoupling with caching or DNS-level distribution, picking CloudFront or Route 53 because they think 'absorbing spikes' means scaling web servers, but the question specifically requires buffering and retry without custom scripts, which only a queue service like SQS provides.
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
✓
Amazon SQS queue
Amazon SQS is the correct choice because it acts as a durable, fully managed message buffer that decouples the web tier from the fulfilment workers. When bursts of orders arrive, SQS queues the messages and allows workers to poll at their own pace, absorbing spikes without data loss. The built-in retry logic (visibility timeout and dead-letter queue) ensures failed processing attempts are automatically retried, and no custom operational scripts are needed.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
AWS WAF
Why it's wrong here
AWS WAF filters HTTP traffic against web exploits at the edge; it cannot queue, buffer or retry messages, so bursts still hit fulfilment workers directly and requests are lost. It is tempting because WAF is the standard choice for shielding web tiers from malicious or excessive requests, but that is filtering, not durable decoupling.
- ✗
Amazon CloudFront
Why it's wrong here
CloudFront caches and distributes content at edge locations; it provides no durable queue, so order messages cannot be buffered or retried and spikes reach workers unchanged. It is tempting because CloudFront absorbs traffic volume, but that applies to cacheable HTTP content, not stateful order processing requiring persistence.
- ✓
Amazon SQS queue
Why this is correct
Amazon SQS decouples the web tier from fulfilment workers, buffering burst order volumes so spikes are absorbed rather than dropped. Its native at-least-once delivery and visibility-timeout retry mechanism reprocess failed messages without custom operational scripts, satisfying the no-scripts constraint.
- ✗
Amazon Route 53 weighted routing
Why it's wrong here
Route 53 weighted routing distributes DNS answers across endpoints; it cannot buffer messages or retry failed fulfilment calls, so bursts would still be lost. It is tempting because it balances traffic, but it is correct for steering clients between healthy regions, not for decoupling tiers with durable queueing.
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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.