Monolithic Architecture¶

Category: Architecture Tags: monolith, java, kubernetes, devops

Overview¶

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.

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.

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.

When To Use It¶

Small team or startup phase
Limited domain complexity
Fast prototyping required

Implementation Examples¶

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¶

Keep modules logically separated inside the monolith
Use clear package structures to isolate business domains
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/