Node.js Express Application in Kubernetes

A simple Node.js Express application containerized with Docker and deployed to Kubernetes.

📋 Table of Contents

• Features
• Quick Start
• Architecture
• Application Endpoints
• Configuration
• Troubleshooting

✨ Features

• Containerized Node.js Express app using Alpine Linux
• Kubernetes deployment with 5 replicas
• Load balancing via Kubernetes Service
• Health check endpoint (/health)
• ES Modules support

🚀 Quick Start

Prerequisites

• Docker
• Kubernetes cluster (Minikube, Docker Desktop, etc.)
• kubectl

Build & Deploy

# Build Docker image
docker build -t node-express-app:1.0.0 .

# For Minikube
eval $(minikube docker-env)
docker build -t node-express-app:1.0.0 .

# Deploy to Kubernetes
kubectl apply -f deployment.yaml
kubectl apply -f service.yaml

# Verify
kubectl get pods
kubectl get services

# Access application
kubectl port-forward service/node-express-service 8080:80
# Open http://localhost:8080

🏗️ Architecture

Kubernetes Cluster
    │
    ├── Service (ClusterIP:80)
    │   └── Load Balances Traffic
    │
    └── Deployment (5 Replicas)
        ├── Pod 1 → Node.js App :3000
        ├── Pod 2 → Node.js App :3000
        ├── Pod 3 → Node.js App :3000
        ├── Pod 4 → Node.js App :3000
        └── Pod 5 → Node.js App :3000

Components:

• Application: Express server on port 3000
• Docker: node:alpine base image
• Deployment: 5 pod replicas for high availability
• Service: ClusterIP with load balancing

🔌 Application Endpoints

Endpoint	Method	Description
/	GET	Returns "Hello World, I am Pod "
/health	GET	Returns "OK" (status 200)

⚙️ Configuration

Docker

• Base Image: node:alpine
• Port: 3000
• Command: npm start

Kubernetes

• Deployment: 5 replicas, image node-express-app:1.0.0
• Service: ClusterIP, port 80 → targetPort 3000

🔧 Troubleshooting

# Check pod status
kubectl get pods
kubectl describe pod <pod-name>
kubectl logs <pod-name>

# Check service
kubectl get services
kubectl describe service node-express-service

# View all resources
kubectl get all -l app=node-express-app-pod

Common Issues:

• Image pull errors: Use eval $(minikube docker-env) for Minikube
• Port conflicts: Use different port in port-forward command
• Pods not starting: Check logs with kubectl logs <pod-name>

📝 Project Structure

├── Dockerfile          # Docker image configuration
├── deployment.yaml     # Kubernetes deployment
├── service.yaml        # Kubernetes service
├── index.mjs           # Express application
└── package.json        # Node.js dependencies

🧹 Cleanup

kubectl delete -f deployment.yaml
kubectl delete -f service.yaml

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👤 Author

Belal Mahmoud - DevOps Engineer

• GitHub: https://github.com/Belal2015
• LinkedIn: https://www.linkedin.com/in/belal-mahmoud-devops/
• Email: belalmahmoud8183@gmail.com

📜 License

This project is licensed under the MIT License. See the LICENSE file for details.

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Happy Deploying! 🚀