Microservices Fundamentals Quiz: Real-World Interview Essentials Quiz

Test your understanding of microservices architecture, key benefits, communication methods, and practical scenarios with this easy microservices interview questions quiz. Perfect for beginners and professionals preparing for job interviews or seeking to strengthen their fundamentals in distributed systems.

1. Definition of Microservices

   Which of the following best describes a microservices architecture in software development?

   1. A software model that requires all components to share a single database
   2. A client-server model with thick clients
   3. An application built as small, independently deployable services
   4. A single large application with tightly coupled components

   Explanation: Microservices architecture divides applications into small, independently deployable services, each responsible for a specific business function. Unlike monolithic architectures, microservices do not form one large, tightly coupled application. Sharing a single database is not required, as each service typically manages its own data. Finally, the architecture is not defined by the client-server model with thick clients.

2. Key Benefit of Microservices

   Which of the following is a primary benefit of using microservices instead of a monolithic architecture?

   1. Single-point-of-failure for the entire application
   2. Easier scalability by allowing individual services to scale independently
   3. Increased coupling between software components
   4. All features must always be deployed together

   Explanation: A core advantage of microservices is that individual services can be scaled based on demand, making resource use efficient. Deploying all features together and increased coupling are typical of monolithic, not microservices, architectures. Single-point-of-failure is reduced in microservices, not increased.

3. Service Communication

   How do microservices typically communicate with each other in a distributed system?

   1. Using USB drives to exchange data
   2. Through REST APIs and asynchronous messaging queues
   3. By sharing function pointers in the same memory space
   4. By calling system commands directly

   Explanation: Microservices often use REST APIs for synchronous communication and messaging queues (like RabbitMQ) for asynchronous messaging. Sharing function pointers requires shared memory, which isn't feasible between separate services. Transferring data via USB drives is impractical and unrelated, and calling system commands directly does not facilitate service-to-service communication.

4. Monolithic vs. Microservices

   In a real-world banking system, how would microservices approach differ from a monolithic one regarding application structure?

   1. Features are separated by user type, not by business function
   2. All features are implemented in one large codebase
   3. Each major feature, like login and transaction, has its own independent service
   4. The database is always shared among all modules

   Explanation: Microservices separate application features by business function, such as login or transactions, giving each its own service. A monolithic approach combines all features into one codebase. Separating by user type isn't a distinguishing factor for microservices, and sharing a single database is common in monoliths, not best practice for microservices.

5. Service Discovery Purpose

   What is the primary purpose of service discovery in microservices architectures?

   1. Allowing services to locate each other dynamically at runtime
   2. Encrypting messages between services
   3. Upgrading all services simultaneously
   4. Ensuring each service runs on a separate physical server

   Explanation: Service discovery enables services to find each other's network addresses dynamically, avoiding hardcoded configurations. Encryption is a separate concern, physical separation is not required, and service discovery is not related to upgrading all services together.

6. Microservices and Failure Handling

   Which pattern is commonly used to prevent failures in one microservice from affecting other services in the system?

   1. Batch processing at midnight
   2. Circuit Breaker Pattern
   3. Single-threaded execution
   4. Hardcoding IP addresses

   Explanation: The Circuit Breaker Pattern helps isolate problems in a failed service, protecting the rest of the system. Hardcoding IP addresses reduces flexibility and doesn't address failures. Single-threaded execution and batch processing relate to how tasks are run, not failure isolation.

7. Microservices Data Consistency

   Which approach helps maintain data consistency across different microservices with separate databases?

   1. Manual file transfers
   2. Saga Pattern
   3. Infinite retry on failure
   4. Direct table joins across databases

   Explanation: The Saga Pattern coordinates distributed transactions through a series of steps and compensations. Direct table joins are not recommended across different databases in microservices. Manual file transfers and infinite retries are unreliable and risk introducing inconsistencies.

8. Technology Flexibility in Microservices

   Why do microservices support technology flexibility better than monolithic systems?

   1. They cannot be deployed independently
   2. They require only one centralized database
   3. Each service can use a different programming language or framework suited to its need
   4. All services must use the same programming language

   Explanation: Microservices allow teams to choose the best technology stack for each service, increasing flexibility. Mandating a single language and centralized database are monolithic limitations. The ability to deploy independently is a key microservices benefit.

9. Scaling in Microservices

   How does scaling work in a microservices architecture when only one service is experiencing high load?

   1. Scaling is not possible in microservices
   2. Only the high-load service can be scaled independently
   3. The affected service must be removed
   4. All services must be scaled together

   Explanation: Microservices enable scaling individual services facing high demand without impacting others. Unlike monoliths, not all services require simultaneous scaling. Saying scaling isn't possible is false, and removal of the affected service is not a solution.

10. Fault Isolation Example

    If the payment service fails in an e-commerce microservices system, how would the architecture typically respond to avoid total checkout failure?

    1. The entire checkout process fails for all users
    2. Automatic deletion of all orders
    3. The order can be marked 'Pending Payment' and retried later
    4. All other services stop working

    Explanation: Microservices fault isolation allows a specific service failure (like payments) to be handled with fallbacks, such as marking orders as pending and retrying. In a properly built system, services continue to operate, and destroying orders or stopping all services is inappropriate.

11. Microservices Communication Example

    In a food delivery app, how can the Order Service inform the Delivery Service of a new order using a typical microservices pattern?

    1. By editing the delivery service code
    2. By placing a message on a messaging queue
    3. By using a shared memory buffer
    4. By writing directly into the delivery database

    Explanation: Services often communicate events through asynchronous messaging queues, promoting decoupling. Writing directly into another service's database is not recommended, editing code does not send information, and shared memory isn't feasible between separately deployed services.

12. Why Use Service Registry?

    What is a core function of a service registry in microservices architecture?

    1. Allowing administrators to change user passwords
    2. Providing authentication to external users
    3. Encrypting all service-to-service traffic by default
    4. Tracking the locations of all available service instances

    Explanation: A service registry maintains information about service instances, enabling dynamic discovery. Authentication and encryption are additional considerations but not core registry functions, and password management for users is unrelated to a service registry’s primary role.

13. Independent Deployment

    What does independent deployment mean in the context of microservices?

    1. Deployment is only done manually
    2. All services must be deployed at once
    3. Each service can be updated and deployed without redeploying the entire application
    4. All deployments must use identical technology stacks

    Explanation: Independent deployment is a key feature of microservices, allowing faster and more frequent releases for individual services. Deploying all services simultaneously, mandating manual deployment, or using identical stacks restricts this flexibility.

14. Loose Coupling Advantage

    Why is loose coupling important in microservices architecture?

    1. It allows changes in one service without impacting others
    2. It ensures all services use one network port
    3. It requires all services to share code
    4. It prevents adding new services to the application

    Explanation: Loose coupling lets services evolve independently, reducing the ripple effect of changes. Sharing code or network ports increases coupling and complexity. Preventing addition of new services goes against scalability and flexibility goals.

15. Event Sourcing Use Case

    What does event sourcing provide in microservices systems that manage transactions?

    1. A shared disk drive for all services
    2. An interface to modify any service at runtime
    3. A log of state changes as events, which acts as a reliable data source
    4. A static configuration file for the network

    Explanation: Event sourcing records every state change as an event, which can be replayed for consistency or recovery. Shared disk drives and network files are not related to the concept. Modifying services at runtime is not event sourcing.

16. Handling Multiple Databases

    Why do microservices often have separate databases instead of a single shared database?

    1. To increase code duplication
    2. To boost latency and slow down transactions
    3. To ensure better autonomy and fault isolation for each service
    4. To make deployment of services more complex intentionally

    Explanation: Having separate databases lets each service evolve independently and isolates failures. Increased code duplication and deployment complexity are not intentional objectives. Shared databases can create bottlenecks and tight coupling, not lower latency.