CV0-004 Deployment Practice Question
A cloud architect is deploying a serverless application using AWS Lambda. The application must process messages from an Amazon SQS queue. The messages are expected to be processed in order, and the application must handle failures without losing messages. Which configuration should be used?
⚠ Common exam trap
The trap here is assuming that standard SQS queues preserve order or that SNS can provide durable, ordered delivery.
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 an SQS FIFO queue as the event source for the Lambda function and configure a dead-letter queue for the source queue.
SQS FIFO queues guarantee message order and support dead-letter queues for failed messages. Using a FIFO queue as the Lambda event source ensures ordered processing, and the DLQ captures messages that cannot be processed, preventing loss. The other options either lack ordering guarantees or use the wrong service.
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 Kinesis Data Streams as the event source and configure the Lambda function to process records in batches.
Why it's wrong here
Kinesis Data Streams can provide ordered processing per shard, but it requires managing shards and is more complex. However, the scenario specifically mentions SQS queue, and Kinesis is a different service. While Kinesis can meet ordering, it is not the correct choice because the requirement is to process messages from an SQS queue.
- ✗
Configure the Lambda function with an SQS trigger and set the batch size to 10, and enable a dead-letter queue for the source queue.
Why it's wrong here
Using a standard SQS queue with a Lambda trigger does not guarantee ordered processing because standard queues are best-effort ordering. A dead-letter queue helps with failure handling but does not ensure order. This configuration does not meet the requirement for ordered message processing.
- ✗
Create an SNS topic and subscribe the Lambda function to it, then publish messages to the topic.
Why it's wrong here
SNS is a pub/sub service that does not guarantee message ordering or persistence. Messages are pushed to subscribers and can be lost if the Lambda function fails. It does not provide the ordered processing or failure recovery needed for this scenario. Therefore, it is not suitable.
- ✓
Use an SQS FIFO queue as the event source for the Lambda function and configure a dead-letter queue for the source queue.
Why this is correct
SQS FIFO queues provide strict message ordering and exactly-once processing. Configuring a dead-letter queue for the source queue ensures that messages that fail processing are moved to a DLQ after a specified number of attempts, preventing message loss. This meets both the ordering and failure handling requirements.
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 and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This CV0-004 practice question is part of Courseiva's free CompTIA 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 CV0-004 exam.