SAA-C03 Design Resilient Architectures Practice Question
A inventory service uses Lambda functions that call an unreliable third-party API. Failed events must be retained for later investigation after retries are exhausted. What should be configured? The design must avoid adding custom operational scripts.
⚠ Common exam trap
Many candidates confuse Lambda's DLQ/failure destination with other error-handling mechanisms like SQS redrive policies or CloudFront custom error pages, which serve different purposes and operate at different layers of the architecture.
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
✓
A Lambda dead-letter queue or failure destination
A Lambda dead-letter queue (DLQ) or failure destination allows you to capture events that have exhausted all retry attempts from an asynchronous invocation. When the Lambda function fails after the maximum retries (default 3), the event is sent to the configured SQS queue or SNS topic for later investigation, without requiring custom scripts or manual polling.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Lambda reserved concurrency set to zero
Why it's wrong here
Reserved concurrency set to zero disables the function entirely, so no events are processed and none are retained for investigation. It is tempting because reserved concurrency genuinely throttles a function to protect downstream systems, but the requirement is post-retry retention of failed events, which an on-failure destination or dead-letter queue delivers.
- ✓
A Lambda dead-letter queue or failure destination
Why this is correct
A dead-letter queue or failure destination captures invocation records after Lambda exhausts its asynchronous retries, retaining failed events for later investigation. This is native Lambda configuration, so no custom operational scripts are needed, satisfying the requirement to retain failures without extra tooling.
- ✗
A larger deployment package
Why it's wrong here
Deployment package size governs cold-start duration and dependency bundling, not what happens to an event after Lambda exhausts its retries. It is tempting because larger packages are a common Lambda tuning topic, but the scenario requires failed events to be retained, which only an on-failure destination or dead-letter queue configuration provides.
- ✗
CloudFront error pages
Why it's wrong here
CloudFront error pages customise responses for HTTP status codes at the edge; they neither capture Lambda asynchronous invocation failures nor retain the event payload for later inspection. This feature fits presenting branded error content to web visitors, whereas failed-event retention requires a dead-letter queue or on-failure destination.
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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JA
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.