AWS Application Integration Services

Question 1

Which Amazon SQS queue type guarantees that messages are delivered in the exact order they are sent and that each message is processed exactly once?

Accepted Answer

FIFO Queue

Answer

FIFO (First-In, First-Out) queues preserve message order and provide exactly-once processing using message deduplication IDs. Standard queues offer higher throughput but provide at-least-once delivery and best-effort ordering.

Question 2

A company wants to fan out a single event notification to multiple subscriber endpoints simultaneously (email, SQS, Lambda, HTTP). Which AWS service is the best fit?

Accepted Answer

Amazon SNS

Answer

Amazon SNS (Simple Notification Service) is a pub/sub messaging service that can push a single message to multiple subscribers—including email, SMS, SQS queues, Lambda functions, and HTTP endpoints—simultaneously. SQS is for point-to-point queuing, EventBridge routes events from sources to targets, and Step Functions orchestrates workflows.

Question 3

What happens to a message in an Amazon SQS standard queue if a consumer retrieves it but does not delete it before the visibility timeout expires?

Accepted Answer

It becomes visible again and can be processed by another consumer

Answer

During the visibility timeout, a message is hidden from other consumers to prevent duplicate processing. If the consumer fails to delete the message before the timeout expires, SQS makes the message visible again so another consumer can process it. It only goes to the Dead-Letter Queue after exceeding the configured maximum receive count.

Question 4

Amazon EventBridge (formerly CloudWatch Events) uses 'rules' to route events. What is the primary mechanism a rule uses to match incoming events?

Accepted Answer

Event patterns (JSON pattern matching against event fields)

Answer

EventBridge rules use event patterns—JSON objects that match against specific fields of incoming events (e.g., source, detail-type, account, region). When an event matches the pattern, the rule routes it to one or more targets such as Lambda, SQS, or Step Functions.

Question 5

Which AWS service is best suited for coordinating a multi-step, long-running business workflow that includes human approval steps, error handling, and retries across multiple AWS services?

Accepted Answer

AWS Step Functions

Answer

AWS Step Functions is a serverless orchestration service that lets you model workflows as state machines using Amazon States Language. It natively supports sequential and parallel execution, retries, error catching, wait states for human approvals (via task tokens), and integration with dozens of AWS services.

AWS Practice Test

AWS Practice Test

AWS Application Integration Services