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Nikko Ferwelo
Nikko Ferwelo

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📝Microservices Interview Cheat Sheet

1. Microservices Architecture 🏗️

  • Definition: A software architecture style where applications are composed of small, independent services that communicate over a network.
  • Advantages: Scalability, flexibility, independent deployment, resilience, and better fault isolation.
  • Challenges: Complexity in management, network latency, distributed data management, and need for strong DevOps practices.

2. Service Discovery 🔍

  • Definition: A mechanism to dynamically discover and connect services in a microservices architecture.
  • Tools: Eureka (Netflix), Consul (HashiCorp), Zookeeper (Apache).
  • Patterns: Client-side discovery, Server-side discovery.

3. API Gateway 🚪

  • Definition: An entry point for client requests, routing them to the appropriate services.
  • Responsibilities: Request routing, composition, and protocol translation.
  • Tools: Kong, NGINX, Zuul (Netflix).

4. Communication Patterns 💬

  • Synchronous Communication: Direct service-to-service communication, typically via HTTP/REST or gRPC.
  • Asynchronous Communication: Communication via messaging systems like RabbitMQ, Kafka, or AWS SQS.
  • Pattern: Request-Response, Event-driven, Publish-Subscribe.

5. Data Management in Microservices 🗄️

  • Database per Service: Each service manages its own database schema, promoting data autonomy.
  • Challenges: Maintaining data consistency across services, distributed transactions.
  • Solutions: Eventual consistency, Saga Pattern, CQRS (Command Query Responsibility Segregation).

6. Circuit Breaker Pattern 🔄

  • Definition: A design pattern used to detect failures and encapsulate the logic of preventing a failure from constantly recurring.
  • Tools: Hystrix (Netflix), Resilience4j.
  • Usage: To prevent cascading failures and improve fault tolerance.

7. Service Resilience & Fault Tolerance 🛡️

  • Techniques: Retry logic, timeout settings, fallback methods.
  • Patterns: Bulkhead Pattern, Retry Pattern, Timeout Pattern.
  • Tools: Hystrix, Resilience4j.

8. API Versioning 📅

  • Definition: Managing changes in APIs without breaking existing client implementations.
  • Techniques: URI versioning, query parameter versioning, custom headers.
  • Strategy: Deprecate old versions and maintain backward compatibility.

9. Monitoring & Logging 🖥️

  • Importance: Critical for understanding the behavior and performance of microservices.
  • Tools: Prometheus, Grafana, ELK Stack (Elasticsearch, Logstash, Kibana), Zipkin (Distributed tracing).
  • Best Practices: Centralized logging, distributed tracing, metrics collection.

10. Security in Microservices 🔐

  • Techniques: OAuth2, JWT (JSON Web Tokens) for authentication and authorization.
  • Challenges: Securing inter-service communication, managing secrets.
  • Tools: Spring Security, Keycloak, Vault (HashiCorp).

11. Containerization & Orchestration 📦

  • Containers: Microservices are often deployed in containers for consistency across environments.
  • Tools: Docker, Podman.
  • Orchestration: Kubernetes for automating deployment, scaling, and operations of containers.

12. Continuous Integration/Continuous Deployment (CI/CD) 🚀

  • Importance: Automates the process of testing, building, and deploying microservices.
  • Tools: Jenkins, GitLab CI, CircleCI.
  • Best Practices: Automated testing, blue-green deployments, canary releases.

13. Event-Driven Microservices 🔔

  • Definition: Microservices that communicate through events, allowing loose coupling and scalability.
  • Tools: Kafka, RabbitMQ, AWS SNS/SQS.
  • Patterns: Event sourcing, CQRS.

14. Domain-Driven Design (DDD) in Microservices 📚

  • Definition: An approach to software development that focuses on modeling the business domain.
  • Concepts: Bounded Contexts, Aggregates, Entities, Value Objects.
  • Usage: Helps in defining service boundaries in a microservices architecture.

15. Testing Strategies 🧪

  • Types of Tests: Unit testing, integration testing, contract testing, end-to-end testing.
  • Tools: JUnit, TestNG, Postman, WireMock (for mocking services).
  • Best Practices: Automation, CI/CD integration, use of test doubles.

Final Tips

  • Understand the Basics: Know the core principles of microservices.
  • Hands-on Practice: Work with tools like Docker, Kubernetes, and Spring Boot.
  • Stay Updated: Microservices evolve quickly; keep up with the latest trends and best practices.

Good luck with your interview!

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