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Navigating the complex world of microservices can be a difficult journey, especially when you’re standing outside the door of an interview room. Whether you’re trying to build your tech career or you are a seasoned professional with years of experience under your belt, mastering the art of microservices interview questions is key to unlocking new opportunities.
Let’s take a look into most commonly asked microservices interview questions for both freshers and experienced.
Microservices Interview Questions for Freshers
1. What are microservices?
Microservices are a software architecture style that structures an application as a collection of loosely coupled services, which implement business capabilities , is basically an SDLC approach in which large applications are built as a collection of small functional modules. It is one of the most widely adopted architectural concepts within software development. In addition to helping in easy maintenance, this architecture also makes development faster.
Each service is self-contained and should implement a single business function.
- Modular Approach: Microservices architecture breaks down an application into small, modular services.
- Independence: Each service runs its own process and communicates with lightweight mechanisms, often an HTTP resource API.
- Domain-focused: Services are organized around business capabilities and independently deployable by fully automated deployment machinery.
- Decentralized Control: Microservices architectures are decentralized, both in data management and governance.
2. Can you explain the difference between Monolithic and Microservices architecture?
In a monolithic architecture, all components of the application are integrated into a single codebase and operate as a single unit. Whereas in microservices, the architecture breaks down the application into a collection of smaller, interconnected services that operate independently.
3. What are the advantages of microservices?
Advantages include improved scalability, flexibility in using different technologies, easier deployment, and enhanced fault isolation.
- Scalability: Services can be scaled independently, allowing for more efficient use of resources and improving application responsiveness.
- Technology Diversity: Teams can choose the best technology stack for their service, rather than being confined to a monolithic architecture’s technology.
- Resilience: Failure in one service doesn’t necessarily bring down the whole system, improving overall system resilience.
- Faster Time to Market: Independent service development and deployment speed up the delivery of new features and bug fixes.
4. What is a Container, and why is it important in Microservices?
A container is basically a package that packages an application and its dependencies together in a form that can run across any computing environment. In microservices, containers offer a lightweight way to ensure consistency across different environments, aiding in the deployment and scalability of services.
5. How do microservices communicate with each other?
Microservices commonly communicate through APIs, usually RESTful APIs or messaging queues like RabbitMQ and Kafka, to asynchronously exchange data.
6. What is an API Gateway?
An API Gateway is a management tool that sits between a client and a collection of backend services, acting as a reverse proxy to accept all application programming interface (API) calls, aggregate the various services required to fulfill them, and return the appropriate result.
- Unified Entry Point: Serves as the single entry point for all client requests, directing them to the appropriate microservices.
- Authentication and Security: Can enforce authentication and authorization, ensuring that only valid requests reach the services.
- Rate Limiting and Analytics: Can handle rate limiting to prevent overuse of resources and provide analytics for API usage patterns.
7. Explain the concept of Service Discovery.
Service Discovery is a process in microservices architectures where services can dynamically discover and communicate with each other. It involves maintaining a list of services so that they can find and communicate with each other over the network.
8. What are the challenges of microservices?
Challenges include complexity in managing multiple services, data consistency, inter-service communication, and implementing changes across services.
9. What is Continuous Integration/Continuous Deployment (CI/CD) in the context of microservices?
CI/CD is a method to frequently deliver apps to customers by introducing automation into the stages of app development. In microservices, CI/CD automates the deployment of each service independently, allowing for rapid updates.
10. What is Domain-Driven Design (DDD)?
DDD is an approach to software development that centers on the complexity of the domain to create a complex design based on both the domain and the domain logic.
- Complexity Management: DDD tackles the complexity of business domains to create effective models that reflect a deep understanding of the domain.
- Ubiquitous Language: Promotes a common language between developers and domain experts, minimizing miscommunication.
- Bounded Contexts: Encourages division of the domain into manageable contexts, aligning with microservices’ boundaries for clearer service definitions.
11. How do you monitor microservices?
Monitoring can be achieved through tools like Prometheus, Grafana, and ELK stack, focusing on metrics, logs, and traces to ensure performance and health.
12. What is a Circuit Breaker pattern?
The circuit breaker pattern is used to identify failures and capture the reasoning behind holding them from occurring constantly, during maintenance, during an unplanned external system outage, or during unexpected system problems.
13. How can you ensure security in microservices?
Security measures include implementing authentication and authorization, secure communication channels (like SSL/TLS), API gateways for secure access, and regular vulnerability assessments.
14. What role does a Config Server play in microservices?
A Config Server centralizes external configurations for microservices, making management easier and enabling dynamic changes without redeployment.
15. What is the significance of Docker in microservices?
Docker containers offer a consistent and isolated environment for microservices, simplifying dependency management and making the application easier to deploy, scale, and maintain across various environments.
In simple words it is a tool designed to make it easier to create, deploy and run applications by using containers.
- Docker packages and application and all its dependencies in a virtual container that can run on any Linux server.
- Each container runs as an isolated process in the user space and takes up less space than regular VM’s due to their layered architecture.
Microservices Interview Questions for Experienced
1. How do you manage data consistency across microservices?
Techniques include using distributed transactions, event sourcing, and the Saga pattern, each helping maintain consistency without compromising service independence.
2. Explain the Saga pattern in microservices.
The Saga pattern manages data consistency across services in a microservices architecture through a sequence of local transactions where each transaction updates data within a single service.
- Transactional Integrity: Maintains data consistency across services without the need for distributed transactions by using a sequence of local transactions.
- Compensation Actions: If a local transaction fails, Saga performs compensatory actions to undo or mitigate the impact of previously completed transactions, ensuring system integrity.
- Event/Message Driven: Sagas can be orchestrated using an event/message-driven approach, where services produce and listen to events to trigger subsequent local transactions.
3. Discuss strategies for microservices deployment.
Strategies include blue-green deployment, canary releases, and rolling updates, each designed to reduce downtime and risk by gradually deploying new versions of services.
4. How do you handle transaction management in microservices?
Handling transactions involves implementing compensating transactions for rollback, using the Saga pattern, or relying on distributed transactions with tools like 2PC (Two-Phase Commit).
- Avoiding Distributed Transactions: Prefers local transactions and compensating transactions over complex and heavy distributed transaction protocols.
- Eventual Consistency: Accepts eventual consistency over immediate consistency to ensure system responsiveness and availability.
- Idempotency: Ensures operations can be retried without side effects, crucial for handling partial failures and ensuring data consistency.
5. What is the API Composition pattern?
It’s a pattern where a composite service aggregates results from multiple services and returns a unified response, reducing the number of round-trip calls between services and clients.
6. How do you ensure high availability in microservices?
High availability can be ensured through designing for failure, including implementing retries, timeouts, circuit breakers, and replicating services across different zones or regions.
7. What is the difference between orchestration and choreography in microservices?
Orchestration involves a central controller dictating the interaction between services, while choreography relies on each service deciding when and how to interact, promoting decentralization.
- Orchestration: A central orchestrator (service) explicitly directs other services on what to do and when to do it, often leading to tighter coupling and a single point of failure but easier logic control.
- Choreography: Services work independently based on events, reducing central management and promoting a more decentralized, resilient system structure.
8. How do microservices impact DevOps?
Microservices enhance DevOps by enabling smaller, focused teams to own the entire lifecycle of a service, from development to production, fostering a culture of continuous delivery and improvement.
9. Discuss the role of microservices in cloud-native applications.
Microservices are a foundational element of cloud-native applications, offering scalability, flexibility, and resilience by leveraging cloud capabilities like elastic scaling, containers, and managed services.
10. What is OAuth 2.0?
- OAuth 2.0 is the industry standard protocol for authorization.
- OAuth 2.0 can be achieved in different ways, that is with different grant types.
- Authorization code and Client credentials are the most commonly used grant type expert.
11. Explain the principles of resilient software design in microservices.
Principles include designing for failure (anticipating and gracefully handling failures), redundancy (avoiding single points of failure), loose coupling (independent service operation), and automation (for recovery processes).
12. Explain type of tests mostly used in Microservices.
As there are multiple microservices working together, microservice testing becomes quite complex when working with microservices. Consequently, tests are categorized according to their level:
- Botton-level tests: The bottom-level tests are those that deal with technology, such as unit tests and performance tests. This is a completely automated process.
- Middle-level tests: In the middle, we have exploratory tests such as stress tests and usability tests.
- Top-level tests: In the top-level testing, we have a limited number of acceptance tests. The acceptance tests help stakeholders understand and verify the software features.
13. Describe the concept of a Sidecar pattern in microservices.
The Sidecar pattern attaches a secondary application or service to a primary application, providing supporting features like logging, monitoring, configuration, and networking services without changing the primary application.
14. How do you approach logging and tracing in a distributed microservices environment?
Implementing centralized logging with tools like ELK Stack, and distributed tracing with tools like Jaeger or Zipkin, helps in aggregating logs and traces from all services to diagnose and monitor issues.
- Centralized Logging: Aggregates logs from all services into a centralized logging system (e.g., ELK stack), facilitating cross-service error tracking and analysis.
- Distributed Tracing: Implements unique identifiers for transactions or user requests as they traverse through services, allowing for detailed performance and error analysis across the microservice architecture.
15. Discuss the importance of event-driven architecture in microservices.
Event-driven architecture is crucial for enabling loosely coupled services to react to state changes or important events efficiently, enhancing system responsiveness and scalability.
- Decoupling: Services operate independently, reacting to events rather than being directly invoked, which reduces dependencies and tight coupling.
- Scalability & Flexibility: Services can be scaled up or down as needed based on demand, and new services can be added without disrupting existing functionality.
- Reactivity: Systems are more responsive and can better handle asynchronous operations, leading to improved user experiences.
Conclusion
Microservices architecture is a method of developing a large-scale application as a collection of small autonomous services developed for a business domain.
This list of Microservices interview questions was carefully constructed to assist the development community in their interviews. Hope these Microservices Interview Questions would be helpful for your interview.
Do let us know in the comment sections below.👇
References
- API: https://www.postman.com/
- Microservices: https://microservices.io/
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Multiple Choice Questions (MCQ’s)
1. What is the primary advantage of using a microservices architecture over a monolithic architecture?
2. What is the primary function of an API Gateway in a microservices architecture?
3. Which design pattern is used to manage data consistency in a microservices architecture?
4. In microservices, what is the primary purpose of using containers like Docker?
5. Which principle is NOT a part of resilient software design in microservices?
6. What is the primary role of a Config Server in microservices?
7. Which of the following is a challenge commonly associated with microservices?
8. Which pattern is used to handle failures and encapsulate the logic of preventing a failure from constantly recurring?
9. What is the primary benefit of using Domain-Driven Design (DDD) in microservices?
10. Which tool is commonly used for monitoring and logging in a microservices environment?
Frequently Asked Questions
The 3 C’s of microservices are:
(i) Componentize
(ii) Collaborate, and
(iii) Connect.
Three types of Microservices are:
- Domain Microservices.
- Integration Microservices.
- Unit-of-work Microservices.
An API gateway is positioned between client apps and the backend microservices, functioning as a reverse proxy. It covers up the complexity of services in the backend and offers a single point of entry.
Check above for detailed explanation.👆
Explain about the architecture, check the first question discussed above.👆
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