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?
⚠ Common exam trap
Many exam-takers confuse DLQs with retry mechanisms or think that increasing function resources (like memory or package size) will prevent failures, when in fact DLQs are the only way to durably capture events after retries are exhausted.
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
Lambda dead-letter queues (DLQs) or failure destinations are the correct mechanism to retain failed events after all retries are exhausted. When a Lambda function fails to process an event (e.g., from an asynchronous invocation), the service automatically retries twice. If those retries fail, the event can be sent to an SQS queue or SNS topic (DLQ) or to a specified destination (failure destination) for later investigation. This ensures no data loss and provides a durable storage for post-mortem analysis.
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 of zero is a scaling control that throttles every invocation, meaning the function code never runs. This does not preserve failed events for analysis; the asynchronous event is simply retried until Lambda's event-age limit is reached, then discarded if no dead-letter queue or failure destination is configured. It is a way to stop processing, not an error-handling strategy.
- ✓
A Lambda dead-letter queue or failure destination
Why this is correct
Configuring a dead-letter queue (an SQS queue or SNS topic) or an asynchronous failure destination causes Lambda to route the event to that target after the configured retry attempts are exhausted. The original event payload is preserved in the DLQ or delivered to a destination such as SQS, SNS, EventBridge, or another Lambda function, allowing operators to inspect and later reprocess the failed inventory events. This is the correct mechanism for capturing failed asynchronous invocations for analysis.
- ✗
A larger deployment package
Why it's wrong here
Increasing the size of the Lambda deployment package does not affect how the invocation service handles retries or where failed events are routed. Package size influences cold-start duration and is constrained by Lambda's 250 MB unzipped limit, but it has no relationship to event preservation or error-handling configuration. A larger package cannot capture or persist an event that has exhausted its retry attempts.
- ✗
CloudFront error pages
Why it's wrong here
CloudFront custom error pages are intended to replace default HTTP error responses returned to clients when an origin, such as an API or web server, returns an error. CloudFront operates at the CDN layer and has no visibility into Lambda's asynchronous event processing pipeline, so it cannot intercept or preserve a failed Lambda invocation. Thus it is unrelated to retaining failed inventory events for troubleshooting.
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 |
Go deeper
Related to this question
About these practice questions
One of 935 original SAA-C03 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 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.