Event-Driven Architecture in Cloud Questions and Answers for Viva

Answer-1: Event-Driven Architecture is a software design pattern in which components communicate by emitting and responding to events rather than direct calls.

Answer-2: The main components are event producers, event routers (or brokers), and event consumers.

Answer-3: An event is a significant change in state or an occurrence in a system that can trigger actions in other parts of the system.

Answer-4: AWS EventBridge, AWS SNS, AWS SQS, Azure Event Grid, Azure Service Bus, and Google Cloud Pub/Sub.

Answer-5: An event signifies a change or occurrence, while a message is a piece of data sent between services, often with intent and target.

Answer-6: An event producer is a system or component that detects an event and publishes it to an event bus or broker.

Answer-7: An event consumer is a component that subscribes to events and takes action when events are received.

Answer-8: A message broker is middleware that receives, stores, and routes messages or events to their appropriate destinations.

Answer-9: AWS EventBridge is a serverless event bus that connects application data from your apps, SaaS, and AWS services.

Answer-10: Azure Event Grid is a fully managed event routing service that enables reactive programming using events.

Answer-11: Event Grid is designed for eventing (state change notifications), while Service Bus is for enterprise messaging (command-style messages).

Answer-12: A topic is a logical channel to which publishers send messages and subscribers receive messages.

Answer-13: Amazon SNS (Simple Notification Service) is a publish/subscribe service that distributes events to multiple subscribers.

Answer-14: Amazon SQS (Simple Queue Service) decouples microservices and queues messages until they are processed.

Answer-15: The fan-out pattern allows one event to trigger multiple parallel actions by multiple subscribers.

Answer-16: Each microservice publishes and subscribes to events, promoting loose coupling and better scalability.

Answer-17: Event sourcing is a technique where all changes to application state are stored as a sequence of events.

Answer-18: Polling repeatedly checks for updates, whereas event-driven systems react only when an event occurs.

Answer-19: Idempotency ensures that handling the same event multiple times does not produce different results.

Answer-20: Schema evolution refers to the ability to change the structure of event payloads without breaking consumers.

Answer-21: A dead-letter queue stores events that cannot be delivered or processed successfully after multiple attempts.

Answer-22: Pub/Sub allows asynchronous messaging between applications, where publishers send messages and subscribers receive them.

Answer-23: Pub/Sub sends messages to all subscribers, while point-to-point sends each message to one consumer.

Answer-24: Improved scalability, loose coupling, real-time response, fault isolation, and async communication.

Answer-25: Debugging, monitoring, ensuring message order, handling duplicates, and event schema management.

Answer-26: Eventual consistency means that the system will reach a consistent state over time, rather than immediately.

Answer-27: A rule in AWS EventBridge that matches incoming events and routes them to specific targets.

Answer-28: Durable messaging ensures that messages are stored reliably and can be retrieved even after failures.

Answer-29: Azure Logic Apps automate workflows triggered by events, connecting services with minimal code.

Answer-30: Retries are mechanisms to attempt message processing again after a failure.

Answer-31: A trigger initiates a function or workflow in response to an event.

Answer-32: Backpressure is the mechanism of slowing down message production when consumers are overwhelmed.

Answer-33: A message queue is a storage layer where messages are held until they are retrieved by a consumer.

Answer-34: Apache Kafka is a distributed event streaming platform used for high-throughput and durable messaging.

Answer-35: Using event patterns defined in rules to match specific event fields.

Answer-36: Loose coupling allows independent development, deployment, and scaling of services.

Answer-37: A webhook is a way for an application to provide other systems with real-time information through HTTP callbacks.

Answer-38: Event-driven workflows respond instantly to triggers, whereas batch workflows operate on schedules.

Answer-39: Yes, functions like AWS Lambda and Azure Functions are commonly used as consumers in event-driven architectures.

Answer-40: Using tools like CloudWatch, Azure Monitor, distributed tracing, and custom logging.

Answer-41: Exactly-once delivery ensures that each event is delivered and processed only once, which is hard to guarantee.

Answer-42: At-least-once delivery ensures every event is processed, possibly more than once, requiring idempotent consumers.

Answer-43: Event patterns are rules that describe which events should be routed to specific services.

Answer-44: An event bus is a mechanism that routes events from producers to consumers based on defined rules.

Answer-45: Yes, with Pub/Sub models, multiple consumers can act on the same event independently.

Answer-46: A command tells a system to do something, while an event states that something has already happened.

Answer-47: JSON, Avro, Protobuf, and XML are commonly used to structure event data.

Answer-48: Chaining is where one event leads to another, creating a sequence of dependent actions or workflows.

Answer-49: Event mesh is a network of interconnected event brokers that allows events to be routed across platforms.

Answer-50: Because it helps trace and debug the asynchronous flow of events across distributed systems.