📝 Node Blog Application

A full-stack blog application built with Node.js + Express + React, deployed through a complete DevOps pipeline — Docker, Kubernetes (Minikube), Horizontal Pod Autoscaling, CI/CD via GitHub Actions, and load-tested with k6.

This project reimplements a Python/Flask CRUD service from scratch in the Node.js ecosystem and takes it through the entire DevOps lifecycle.

---

🌐 Live Demo

Run locally via Minikube — see Getting Started below.

Docker Hub Image: manches300/node-blog-app:latest

---

🧱 Tech Stack

Layer	Technology
Backend	Node.js 20, Express 4.18
Frontend	React 19, Vite
Database	PostgreSQL 15, Sequelize 6 ORM
Containerization	Docker (multi-stage build), Docker Compose
Orchestration	Kubernetes v1.28 (Minikube)
Autoscaling	Horizontal Pod Autoscaler (HPA)
Load Testing	k6
CI/CD	GitHub Actions (self-hosted runner)

---

✨ Features

• ✅ Full CRUD operations — Create, Read, Update, Delete blog posts
• ✅ React SPA served directly from Express (single port 5000)
• ✅ Multi-stage Docker build — lean Alpine-based runtime image
• ✅ Kubernetes deployment with liveness & readiness probes
• ✅ HPA — auto-scales from 2 to 10 replicas based on CPU/memory
• ✅ Secrets management — sensitive config stored in Kubernetes Secrets, never in Git
• ✅ Self-healing — pods replaced automatically within ~11 seconds of failure
• ✅ CI/CD pipeline — automated build, push to Docker Hub, and deploy on every push to main

---

📁 Project Structure

Node_blog_application/
├── app/                    # Express backend source
├── frontend/               # React + Vite frontend
├── k8s/
│   ├── deployment.yaml     # Kubernetes Deployment
│   ├── service.yaml        # NodePort Service
│   ├── hpa.yaml            # Horizontal Pod Autoscaler
│   └── postgres.yaml       # PostgreSQL Deployment + ClusterIP Service
├── .github/
│   └── workflows/
│       └── ci.yml          # GitHub Actions CI/CD pipeline
├── loadtest.js             # k6 load test script
├── Dockerfile              # Multi-stage Docker build
├── docker-compose.yaml     # Local development stack
├── app.js                  # Express entry point
└── .env.example            # Environment variable template

---

🚀 Getting Started

Prerequisites

• Docker Desktop
• Minikube
• kubectl
• Node.js 20+

---

Option 1 — Run with Docker Compose (Local Dev)

# Clone the repo
git clone https://github.com/manches3003/Node_blog_application.git
cd Node_blog_application

# Copy and configure environment variables
cp .env.example .env

# Start the full stack (app + postgres)
docker compose up --build

App will be available at http://localhost:5000

⚠️ If your database password contains @, it must be percent-encoded as %40 in the DATABASE_URL. See Notes below.

---

Option 2 — Deploy to Kubernetes (Minikube)

# Start Minikube
minikube start --driver=docker

# Enable metrics server (required for HPA)
minikube addons enable metrics-server

# Pull the image into Minikube
minikube image pull manches300/node-blog-app:latest

# Create Kubernetes Secret with your credentials
kubectl create secret generic node-blog-secrets \
  --from-literal=DATABASE_URL="postgresql://postgres:password@postgres:5432/node_blog_db" \
  --from-literal=SECRET_KEY="your-secret-key"

# Deploy PostgreSQL
kubectl apply -f k8s/postgres.yaml

# Deploy the application
kubectl apply -f k8s/deployment.yaml
kubectl apply -f k8s/service.yaml
kubectl apply -f k8s/hpa.yaml --server-side=true

# Wait for rollout
kubectl rollout status deployment node-blog-app --timeout=120s

# Get the app URL
minikube service node-blog-app --url

On Windows with Docker driver, keep the terminal open — the tunnel must stay active for the URL to remain accessible.

---

🌐 API Endpoints

Method	Endpoint	Description
GET	/api/posts	Get all posts
POST	/api/posts	Create a new post
GET	/api/posts/:id	Get a single post
PUT	/api/posts/:id	Update a post
DELETE	/api/posts/:id	Delete a post
GET	/health	Health check (used by probes)

---

⚙️ Kubernetes Architecture

Internet
    │
    ▼
NodePort Service (port 30080)
    │
    ▼
Deployment: node-blog-app
├── Pod 1 (node-blog-app)  ─────┐
└── Pod 2 (node-blog-app)       ├── ClusterIP: postgres:5432
        ▲                       │
        │                       ▼
  HPA (min 2 / max 10)    PostgreSQL Pod
  CPU: 50% threshold
  Memory: 70% threshold

Resource limits per pod:

	Request	Limit
CPU	100m	500m
Memory	128Mi	256Mi

---

📊 Load Test Results (k6)

Tested with 500 concurrent virtual users over 100 seconds (5-stage ramp).

Metric	Value	Threshold	Status
Total Requests	77,834	—	✅
Throughput	771 req/s	—	✅
Avg Response Time	3.83 ms	< 2000 ms	✅
Median (p50)	1.66 ms	—	✅
p90	5.78 ms	—	✅
p95	12.05 ms	< 2000 ms	✅
Max Response Time	134.39 ms	—	✅
Error Rate	0.00%	< 50%	✅
Max Virtual Users	500	>= 500	✅

Run the load test yourself

# Install k6: https://k6.io/docs/get-started/installation/
k6 run loadtest.js

---

🔁 CI/CD Pipeline

The GitHub Actions workflow (.github/workflows/ci.yml) triggers on every push to main:

1. Test — Install dependencies, run npm test
2. Build — Install frontend deps, run Vite build
3. Docker — Login to Docker Hub, build & push manches300/node-blog-app:latest
4. Deploy — Setup Minikube, apply all manifests via kubectl

A self-hosted GitHub Actions runner is required because standard hosted runners cannot run a Minikube cluster.

---

🔒 Environment Variables

Copy .env.example to .env and fill in your values:

NODE_ENV=production
PORT=5000
DATABASE_URL=postgresql://postgres:YOUR_PASSWORD@postgres:5432/node_blog_db
SECRET_KEY=your-secret-key-change-in-production

In Kubernetes, these are injected from the node-blog-secrets Secret — never committed to the repository.

---

📝 Notes

Password URL Encoding

If your PostgreSQL password contains special characters like @, you must percent-encode them in the DATABASE_URL:

@ → %40

Minikube Tunnel (Windows)

On Windows with the Docker driver, the terminal running minikube service node-blog-app --url must stay open. Closing it will make the URL inaccessible.

HPA and Metrics Server

The HPA requires the Minikube metrics-server addon. Enable it with:

minikube addons enable metrics-server

---

🐛 Known Challenges & Fixes

Challenge	Fix
ENOENT error on startup	Dockerfile was copying frontend build to /app/public but app.js referenced /app/frontend/dist — fixed by aligning the static path
Docker token error in CI	Docker Desktop access issue during GitHub Actions — regenerated the Docker Hub token
Minikube in GitHub Actions	Standard hosted runners can't run Minikube — switched to a self-hosted runner
@ in DB password	Percent-encoded as %40 in all DATABASE_URL values

---

👨‍💻 Authors

• Keshav Virajbhai Kansara — 100007269@stud.srh-university.de

---

📄 License

This project is for academic purposes. Feel free to reference or fork it for learning.

---

Made with ☕ and way too many kubectl get pods commands