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Cloud Native Chat App DevOps

A production-ready full-stack chat application built using modern DevOps practices.

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Table of Contents

• Cloud Native Chat App DevOps
  • Table of Contents
  • Introduction
  • Features
  • Tech Stack
  • Architecture Overview
  • Project Structure
  • Prerequisites
  • Setup .env
  • Step 1: Build Docker Images
  • Step 2: Apply Kubernetes Manifests
  • Step 3: Verify Deployments
  • Step 4: Configure Hosts File
  • Step 5: Access the App (Important for Ingress)
  • CI/CD (Jenkins)
    • Pipeline Flow
  • Step 6: Common Issues & Fixes
  • Project Notes
  • 👤 About the Architect

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Introduction

This is a production-ready cloud-native chat application demonstrating real-world DevOps practices including CI/CD, containerization, and Kubernetes orchestration.

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Features

• Real-time messaging using Socket.IO
• User authentication (JWT)
• Profile management
• Online/offline user status
• Dockerized frontend & backend
• Kubernetes deployment with Ingress
• MongoDB persistent storage
• CI/CD pipeline using Jenkins

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Tech Stack

• Frontend: React, TailwindCSS, Zustand
• Backend: Node.js, Express, Socket.IO
• Database: MongoDB
• Containerization: Docker
• Orchestration: Kubernetes
• CI/CD: Jenkins
• Ingress: NGINX

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Architecture Overview

User → Browser
       ↓
   Ingress (NGINX)
       ↓
 ┌───────────────┐
 │   Frontend    │
 │   React App   │
 └──────┬────────┘
        ↓ API Calls
 ┌───────────────┐
 │   Backend     │
 │ Node + Socket │
 └──────┬────────┘
        ↓
     MongoDB

CI/CD:
GitHub → Jenkins → Docker → Kubernetes

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Project Structure

full-stack_chatApp/
├── backend/            # Node.js backend
├── frontend/           # React frontend
├── kubernetes/         # Kubernetes manifests (deployments, services, ingress)
├── docker-compose.yml  # Optional local Docker Compose setup
├── Jenkinsfile
└── README.md

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Prerequisites

• Docker Desktop (Kubernetes enabled)
• kubectl
• Node.js >= 18 (optional)
• Git
• Browser

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Setup .env

cd backend

Create .env:

MONGODB_URI=mongodb://mongoadmin:secret@mongodb:27017/dbname?authSource=admin
JWT_SECRET=your_jwt_secret_key
PORT=5001

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Step 1: Build Docker Images

cd backend
docker build -t your-dockerhub/chatapp-backend:latest .

cd ../frontend
docker build -t your-dockerhub/chatapp-frontend:latest .

Push images to Docker Hub:

docker push mayrhatte09/chatapp-backend:latest
docker push mayrhatte09/chatapp-frontend:latest

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Step 2: Apply Kubernetes Manifests

1. Apply namespace:

kubectl apply -f kubernetes/namespace.yaml

2. Apply Persistent Volume & PVC for MongoDB

kubectl apply -f kubernetes/mongodb-pv.yaml
kubectl apply -f kubernetes/mongodb-pvc.yaml

1. Apply MongoDB deployment & service:

kubectl apply -f kubernetes/mongodb-deployment.yaml
kubectl apply -f kubernetes/mongodb-service.yaml

1. Apply backend deployment & service:

kubectl apply -f kubernetes/backend-deployment.yaml
kubectl apply -f kubernetes/backend-service.yaml

5. Apply frontend deployment & service:

kubectl apply -f kubernetes/frontend-deployment.yaml
kubectl apply -f kubernetes/frontend-service.yaml

6. Apply secrets (JWT secret):

kubectl apply -f kubernetes/secrets.yaml

1. Apply Ingress to route chatapp.com:

kubectl apply -f kubernetes/ingress.yaml

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Step 3: Verify Deployments

Check pods:

kubectl get pods -n kubernetes

Check services:

kubectl get svc -n kubernetes

Check ingress:

kubectl get ingress -n kubernetes

Ensure NGINX ingress controller is running:

kubectl get pods -n ingress-nginx
kubectl get svc -n ingress-nginx

(Optional) Port-forwarding:

kubectl port-forward service/backend -n kubernetes 5001:5001
kubectl port-forward service/frontend -n kubernetes 80:80

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Step 4: Configure Hosts File

Ingress uses a custom host (chatapp.com). You need to map it to localhost.

1. Open Notepad as Administrator:

Press Windows Key → type Notepad → Right Click → Run as administrator

1. Open the hosts file:

C:\Windows\System32\drivers\etc\hosts

1. Add the line:

127.0.0.1 chatapp.com

1. Save and flush DNS:

ipconfig /flushdns

1. Verify:

ping chatapp.com
# Should return 127.0.0.1

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Step 5: Access the App (Important for Ingress)

• Frontend: http://chatapp.com/
• Backend: http://chatapp.com/api/

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CI/CD (Jenkins)

Pipeline Flow

1. Push code to GitHub
2. Jenkins pulls code
3. Builds Docker images
4. Pushes to Docker Hub
5. Deploys to Kubernetes

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Step 6: Common Issues & Fixes

Issue	Fix
chatapp.com not working	Check hosts file and run ipconfig /flushdns
Ingress no address	Install ingress controller
Backend not running	Check pod logs
Ingress shows <none> for ADDRESS	Ensure NGINX ingress controller is installed and running
Backend not working	Verify backend service exposes port 5001 and pod is running
Frontend not loading	Check frontend service and pod status
Secret not found	Apply secrets.yaml before backend deployment
MongoDB connection error	Verify MONGODB_URI and MongoDB pod status
Pods stuck in Pending	Check PVC/PV and cluster resources
ImagePullBackOff	Verify image name and push to Docker Hub
CrashLoopBackOff	Check logs and environment variables
Port not accessible	Verify service ports and configuration
Ingress not routing	Check ingress rules and service names
DNS not resolving	Verify hosts file entry
Jenkins pipeline failed	Check Jenkins console logs
Docker build failed	Check Dockerfile and dependencies
Wrong namespace issue	Use -n kubernetes in commands
Socket.IO not working	Check backend port and WebSocket config
CORS error	Enable CORS in backend
Backend API not reachable	Verify backend service and endpoints
MongoDB pod restarting	Check storage and logs
Deployment not updating	Reapply manifests or check image tag
High response time	Check pod resources and scaling
Service not found	Verify service name in configs
Env variables not working	Check .env or Kubernetes secrets
Ingress 502 error	Backend service may be down
Permission denied (Docker/Jenkins)	Check Docker socket permissions

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Project Notes

• MongoDB uses Persistent Volume and PVC to persist data.
• JWT secret stored in Kubernetes Secret and injected into backend.
• Frontend communicates with backend via /api/ routed through Ingress.
• Docker Desktop Kubernetes is for local development; for production, use cloud K8s.

👤 About the Architect

Mayur Hatte DevOps & Cloud Infrastructure Engineer Focused on building self-healing, automated infrastructure. This playbook is a verified asset of MayurHatte09.

_{© 2026 | Mayur Hatte Design System}

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