Web Services and Microservices Questions and Answers for Viva

Answer-1: A Web Service is a software system designed to support interoperable machine-to-machine interaction over a network, typically using protocols like HTTP and XML.

Answer-2: The two main types of Web Services are SOAP (Simple Object Access Protocol) and REST (Representational State Transfer).

Answer-3: A Microservice is an architectural style where an application is structured as a collection of small, loosely coupled services, each responsible for a specific business function.

Answer-4: Web services are a way of communicating over a network, often using XML or JSON, while microservices break an application into small, independently deployable services, each focusing on a single task.

Answer-5: Microservices offer benefits such as scalability, flexibility, ease of deployment, fault isolation, and the ability to use different technologies for different services.

Answer-6: The core principles of Microservices architecture include independent deployability, decentralized data management, fault isolation, and communication through lightweight protocols (e.g., HTTP/REST).

Answer-7: RESTful Web Services are lightweight, use HTTP for communication, and support various data formats like JSON and XML. SOAP Web Services, on the other hand, are heavier, use XML exclusively, and support more complex operations.

Answer-8: REST is simple to implement, supports multiple data formats (e.g., JSON, XML), is stateless, and operates over standard HTTP protocols, making it scalable and easy to use.

Answer-9: A service registry is used in Microservices to keep track of all the available services and their instances, allowing other services to discover and communicate with them.

Answer-10: An API Gateway acts as an entry point for client requests and routes them to the appropriate microservices. It can also handle cross-cutting concerns like authentication, logging, and rate-limiting.

Answer-11: Load balancing distributes client requests across multiple instances of a service to ensure optimal resource utilization and high availability in a microservices architecture.

Answer-12: A monolithic application is built as a single unit where all the components are tightly integrated, making it difficult to scale, update, and maintain.

Answer-13: Microservices offer better scalability, flexibility in technology choices, independent deployments, fault isolation, and improved team autonomy compared to monolithic systems.

Answer-14: SOA is an architectural style where services are provided to other components over a network, often using SOAP and XML to exchange messages.

Answer-15: Microservices often use decentralized data management, where each service manages its own database, ensuring data autonomy and scalability.

Answer-16: An orchestration service coordinates the communication between microservices to handle complex business processes, while each microservice manages its specific functionality.

Answer-17: Microservices communicate with each other through lightweight protocols like HTTP/REST or messaging systems such as RabbitMQ or Kafka.

Answer-18: Challenges include managing distributed systems, ensuring data consistency, handling inter-service communication, monitoring, security, and testing.

Answer-19: A Circuit Breaker is a pattern used to detect failures and prevent an application from repeatedly trying to execute an operation that is likely to fail, thereby improving resilience.

Answer-20: Containers, like Docker, are used to package microservices and their dependencies into isolated environments, making them easy to deploy and manage across different systems.

Answer-21: Security in Microservices can be ensured by implementing HTTPS for communication, using OAuth2 for authentication, securing APIs, and employing API Gateway for centralized security enforcement.

Answer-22: Synchronous communication requires both services to be available for the interaction to take place, while asynchronous communication allows services to communicate independently and handle requests in their own time.

Answer-23: The most common communication protocols for Microservices are HTTP/REST, gRPC, WebSockets, and message brokers like RabbitMQ and Kafka for asynchronous communication.

Answer-24: A service mesh manages and controls communication between microservices, handling concerns like load balancing, service discovery, encryption, and monitoring.

Answer-25: Key features include stateless communication, use of HTTP methods (GET, POST, PUT, DELETE), representation of resources, and support for different data formats (e.g., JSON, XML).

Answer-26: Microservices versioning can be handled using URL versioning, request headers, or by adopting semantic versioning for service APIs.

Answer-27: A RESTful API is an API that adheres to the principles of REST, providing stateless communication, using standard HTTP methods, and representing resources through URLs.

Answer-28: "Stateless" means each request from a client must contain all the information necessary to understand and process the request, with no reliance on previous requests.

Answer-29: Service Discovery is a mechanism that enables microservices to dynamically discover and interact with each other by locating their addresses or endpoints through a registry.

Answer-30: Each microservice typically owns its own database to ensure independence, avoid tight coupling, and improve scalability.

Answer-31: Microservices handle transactions using patterns like Saga or two-phase commit (2PC) to ensure consistency across distributed services.

Answer-32: While both are architectural styles that involve services, Microservices are smaller, independently deployable units, whereas SOA involves larger, more complex services often managed centrally.

Answer-33: Logging in Microservices is crucial for tracking service behavior, detecting errors, and ensuring traceability across distributed services.

Answer-34: An API Gateway is a single entry point for clients to interact with multiple microservices, handling routing, load balancing, authentication, and monitoring.

Answer-35: Microservices use eventual consistency models, and patterns like Event Sourcing and CQRS (Command Query Responsibility Segregation) are employed to maintain data consistency.

Answer-36: Continuous Integration (CI) and Continuous Deployment (CD) automate the testing and deployment of microservices, ensuring faster, more reliable updates to services.

Answer-37: Microservices scale horizontally by adding more instances of a service to handle increased load, ensuring the system remains resilient and responsive.

Answer-38: Decoupling ensures that each microservice can operate independently, allowing changes to one service without affecting others, leading to more flexible and maintainable systems.

Answer-39: Monitoring Microservices involves tracking service performance, uptime, and health using tools like Prometheus, Grafana, or ELK stack for centralized logging and visualization.

Answer-40: The standard status code for a successful HTTP request is 200 OK.

Answer-41: Fault tolerance in Microservices is achieved using patterns like Circuit Breaker, retry mechanisms, and graceful degradation to handle failures and ensure reliability.

Answer-42: Common challenges include handling distributed transactions, data consistency, network latency, service orchestration, and maintaining security.

Answer-43: Microservices scale independently by adding more instances of the service based on demand, often using orchestrators like Kubernetes.

Answer-44: Asynchronous messaging ensures that microservices can operate independently without waiting for responses, improving performance and decoupling the services.

Answer-45: Service decomposition is the process of breaking down a monolithic application into smaller, independently deployable services based on business functionality.

Answer-46: Common patterns include Service Discovery, API Gateway, Circuit Breaker, Event Sourcing, and CQRS (Command Query Responsibility Segregation).

Answer-47: Inter-service communication can be handled using synchronous protocols like HTTP/REST or asynchronous messaging systems like Kafka, RabbitMQ, or ActiveMQ.

Answer-48: API Gateway simplifies communication, centralizes security, enables monitoring, and reduces the number of requests to backend services.

Answer-49: Dependency management ensures that each microservice has its own set of dependencies, preventing conflicts and ensuring isolated environments for each service.

Answer-50: An example is an e-commerce platform where different microservices handle user management, inventory, payments, and orders independently.