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Microservices Architecture

category: Architecture
tags: microservices, java, kubernetes, spring-boot, scalability

Main Topic 1

A Microservices Architecture is a design where an application is composed of small, independent services that communicate over well-defined APIs.

Subtopic A: What It Is

• Each service is independently deployable
• Loosely coupled components
• Polyglot-friendly – different services can use different tech stacks

Subtopic B: Why Use It

• Scalability – Scale services independently based on demand
• Team autonomy – Teams can work on different services
• Resilience – Failure in one service doesn't bring down the whole system

Subtopic C: When To Use It

• Complex domains with multiple teams
• Need for independent scaling
• Continuous delivery and agility are required

Main Topic 2

Code Example (Spring Boot Service)

@RestController
public class OrderController {
    @GetMapping("/orders")
    public List<String> getOrders() {
        return List.of("Order1", "Order2");
    }
}

Infra Example (Kubernetes)

apiVersion: apps/v1
kind: Deployment
metadata:
  name: order-service
spec:
  replicas: 2
  selector:
    matchLabels:
      app: order-service
  template:
    metadata:
      labels:
        app: order-service
    spec:
      containers:
      - name: order-service
        image: myregistry/order-service:latest
        ports:
        - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: order-service
spec:
  selector:
    app: order-service
  ports:
  - port: 80
    targetPort: 8080

Key Concepts Summary

• Decoupled services, each responsible for a specific business function
• Independent deployability and scalability
• Requires API contracts and inter-service communication strategies

Best Practices / Tips

1. Use a service mesh for observability and traffic control
2. Implement circuit breakers and retries
3. Maintain backward-compatible APIs

Common Issues / Troubleshooting

Problem 1: Too much complexity too early

• Cause: Overengineering small systems
• Solution: Consider modular monolith as a stepping stone

Problem 2: Communication failure between services

• Cause: Network or service discovery issues
• Solution: Use Kubernetes Services or a service mesh

References / Further Reading

• https://martinfowler.com/articles/microservices.html
• https://kubernetes.io/docs/concepts/services-networking/service/

Last updated: 2025-08-26 20:00 UTC