Microservices

Overview

Microservices architecture is an approach to developing a single application as a suite of small services, each running in its own process and communicating with lightweight mechanisms, often an HTTP resource API. These services are built around business capabilities and independently deployable.

Key Concepts

1. Independent Deployment

Each service can be updated, deployed, and scaled independently without affecting the entire system.

2. Service Communication

  • Synchronous: REST, gRPC.
  • Asynchronous: Message queues (Kafka, RabbitMQ), Pub/Sub.

3. API Gateway

A single entry point for all clients. It handles requests by routing them to the appropriate backend service, and can also handle cross-cutting concerns like authentication, rate limiting, and logging.

4. Service Discovery

A way for services to find each other's network locations (IP/Port) in a dynamic environment (e.g., Kubernetes).

Trade-offs & Considerations

  • Operational Complexity: Managing dozens or hundreds of services requires robust CI/CD, monitoring, and orchestration (e.g., Kubernetes).
  • Data Consistency: Maintaining consistency across multiple databases is challenging (Saga pattern, 2PC).
  • Network Latency: Inter-service communication adds latency compared to in-process calls in a monolith.

Further Reading