DVA-C02 Development with AWS Services Practice Question
A developer is designing a serverless application that processes images uploaded to an S3 bucket. Each image must be resized and then stored in a different S3 bucket. The process must be asynchronous and fault-tolerant. Which AWS service should trigger the Lambda function?
⚠ Common exam trap
Many exam-takers confuse the service that triggers the Lambda (S3 Event Notifications) with the service that stores or routes the event data (SQS or Step Functions), leading them to pick an option that adds unnecessary complexity or is designed for a different use case.
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 S3 Event Notifications
Amazon S3 Event Notifications are the correct trigger because they natively support event-driven architectures where S3 object creation events (e.g., s3:ObjectCreated:Put) can directly invoke a Lambda function. This enables asynchronous processing of uploaded images without any intermediate polling or custom integration, ensuring fault tolerance through Lambda's built-in retry mechanism and dead-letter queue (DLQ) support.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Amazon S3 Event Notifications
Why this is correct
Amazon S3 Event Notifications are the native mechanism for S3 buckets to publish events, such as object creation (s3:ObjectCreated:*), to various destinations. These notifications can directly invoke AWS Lambda functions asynchronously, providing a highly scalable and decoupled way to trigger serverless processing whenever new data arrives in an S3 bucket. This direct integration eliminates the need for intermediary services for simple object-triggered workflows, making it the most suitable and efficient choice for this scenario.
- ✗
Amazon SQS
Why it's wrong here
While Amazon SQS is an excellent messaging queue for decoupling components and handling asynchronous processing, Amazon S3 cannot directly publish events to an SQS queue. To send S3 object creation events to SQS, you must first configure S3 Event Notifications to target an SQS queue. Therefore, SQS itself is not the mechanism that *triggers* the initial event directly from S3, but rather a potential downstream recipient of an S3 event notification.
- ✗
Amazon API Gateway
Why it's wrong here
Amazon API Gateway is primarily designed to create, publish, maintain, monitor, and secure REST, HTTP, and WebSocket APIs, acting as a front door for applications to access backend services. It is inherently a synchronous request-response service, expecting an immediate response from the backend. For asynchronous processing initiated by data arriving in S3, API Gateway is unsuitable as it does not natively integrate with S3 object events and is not designed for event-driven, non-blocking workflows.
- ✗
AWS Step Functions
Why it's wrong here
AWS Step Functions is a serverless workflow service used to orchestrate complex business processes and long-running tasks by coordinating multiple AWS services into visual workflows. While Step Functions can orchestrate subsequent steps *after* an event occurs, it is not an event source itself that directly triggers from S3 object creation. An S3 Event Notification would first need to invoke a Lambda function, which could then start a Step Functions workflow, making Step Functions a downstream orchestrator, not the initial trigger.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DVA-C02 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 DVA-C02 exam.