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Monolithic Architecture

category: Architecture
tags: monolith, java, kubernetes, devops

Main Topic 1

A Monolithic Architecture is a single-tiered application structure where all functions—UI, business logic, and data access—are tightly coupled and run as one unit.

Subtopic A: What It Is

• Single deployment unit – All code runs in a single application process.
• Shared memory – Components directly invoke one another.
• Common in early-stage applications – Faster to develop and deploy initially.

Subtopic B: Why Use It

• Simplicity – Easier to develop, test, and deploy initially.
• Speed – Fewer moving parts, less orchestration needed.
• Tools – Ideal for small teams or MVPs.

Subtopic C: When To Use It

• Small team or startup phase
• Limited domain complexity
• Fast prototyping required

Main Topic 2

Code Example (Java Spring Boot)

@RestController
public class GreetingController {
    @GetMapping("/greet")
    public String greet() {
        return "Hello from Monolith!";
    }
}

Infra Example (Kubernetes)

apiVersion: apps/v1
kind: Deployment
metadata:
  name: monolith-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: monolith
  template:
    metadata:
      labels:
        app: monolith
    spec:
      containers:
      - name: monolith-container
        image: myregistry/monolith-app:latest
        ports:
        - containerPort: 8080

Key Concepts Summary

• All components packaged into one
• Easy to build, hard to scale and maintain over time
• No network overhead between components

Best Practices / Tips

1. Keep modules logically separated inside the monolith
2. Use clear package structures to isolate business domains
3. Containerize early to enable smooth migration later

Common Issues / Troubleshooting

Problem 1: Hard to scale specific functions

• Cause: Everything is one process
• Solution: Consider breaking into microservices

Problem 2: Deployment downtime

• Cause: One failure can bring down entire app
• Solution: Use rolling updates with health checks in K8s

References / Further Reading

• https://martinfowler.com/bliki/Monolith.html
• https://kubernetes.io/docs/concepts/workloads/controllers/deployment/

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