Quiz App Kubernetes Deployment

A comprehensive deployment of a Flask-based Quiz Application on Kubernetes, featuring user roles, quiz management, and automated testing capabilities.

Project Overview

This project demonstrates deploying a scalable web application using Kubernetes. The application is a quiz platform that supports:

• Different user roles (admin, teacher, student)
• Quiz creation and management
• Timed quiz sessions
• Results tracking and analytics
• Persistent data storage

Technologies Used

• Backend: Python Flask
• Database: SQLite with persistent storage
• Containerization: Docker
• Orchestration: Kubernetes (Minikube)
• Authentication: Flask-Login

Prerequisites

• Docker Desktop
• Minikube
• kubectl
• Python 3.9+
• PowerShell (for Windows) or Bash (for Linux/macOS)

Deployment Architecture

The application is deployed with the following Kubernetes resources:

• Deployment: 3 replicas of the Quiz App container
• Service: NodePort service exposing the application
• ConfigMap: Environment variables configuration
• Secret: Sensitive data storage (credentials, keys)
• PersistentVolume & PVC: For database persistence
• HorizontalPodAutoscaler: Auto-scales based on CPU utilization (2-5 pods)

Quick Start

1. Clone the repository

git clone https://github.com/yourusername/quiz-app-kubernetes.git
cd quiz-app-kubernetes

2. Start Minikube

minikube start --memory=2048 --cpus=2 --driver=docker

3. Configure Docker to use Minikube's daemon

# For PowerShell
& minikube -p minikube docker-env | Invoke-Expression

4. Build the Docker image

docker build -t quiz-app:v1 .

5. Deploy the application

# Apply Kubernetes manifests
kubectl apply -f k8s/pv-pvc.yaml
kubectl apply -f k8s/configmap.yaml
kubectl apply -f k8s/secret.yaml
kubectl apply -f k8s/deployment.yaml
kubectl apply -f k8s/hpa.yaml

# Enable metrics-server for HPA
minikube addons enable metrics-server

6. Access the application

minikube service quiz-app-service --url

7. Automated deployment

Alternatively, run the provided deployment script:

# For PowerShell
.\deploy.ps1

Testing Scenarios

1. Application Availability Test

# Check if the service is available
kubectl get services

# Test application endpoint
minikube service quiz-app-service --url

2. Scaling Test

# Watch the HPA
kubectl get hpa -w

# Generate load in another terminal
kubectl run --rm -it --image=busybox load-generator -- /bin/sh -c "while true; do wget -q -O- http://quiz-app-service; done"

# Watch the pods increase
kubectl get pods -w

3. Rolling Update Test

# Build a new version
docker build -t quiz-app:v2 .

# Perform a rolling update
kubectl set image deployment/quiz-app quiz-app=quiz-app:v2

# Check rollout status
kubectl rollout status deployment/quiz-app

4. Rollback Test

# Rollback to previous version
kubectl rollout undo deployment/quiz-app

# Check rollback status
kubectl rollout status deployment/quiz-app

5. Pod Failure and Self-Healing Test

# Delete a pod and watch Kubernetes recreate it
kubectl delete pod $(kubectl get pods -l app=quiz-app -o jsonpath="{.items[0].metadata.name}")
kubectl get pods -w

6. Persistent Storage Test

# Create data, delete pod, verify data persists after pod recreation

7. Logging Test

# View application logs
kubectl logs $(kubectl get pods -l app=quiz-app -o jsonpath="{.items[0].metadata.name}")

Application Usage

Default Admin Credentials

• Username: admin
• Password: admin123

User Roles

1. Administrator: Manages users (add/remove teachers and students)
2. Teacher: Creates quizzes, views results, analyzes performance
3. Student: Takes quizzes, views personal history and scores

Kubernetes Files Explained

• deployment.yaml: Defines the application deployment with 3 replicas
• service.yaml: Exposes the application via NodePort
• configmap.yaml: Stores environment variables
• secret.yaml: Stores sensitive data (encoded)
• pv-pvc.yaml: Defines persistent storage for the database
• hpa.yaml: Configures auto-scaling based on CPU utilization

Cleanup

# Delete all resources
kubectl delete -f k8s/
# OR
kubectl delete all --all

# Stop Minikube
minikube stop

Project Structure

quiz-app-kubernetes/
├── app.py                  # Main Flask application
├── requirements.txt        # Python dependencies
├── Dockerfile              # Container definition
├── .dockerignore           # Docker build exclusions
├── deploy.ps1              # Deployment automation
├── templates/              # HTML templates
├── k8s/                    # Kubernetes manifests
│   ├── deployment.yaml
│   ├── configmap.yaml
│   ├── secret.yaml
│   ├── pv-pvc.yaml
│   └── hpa.yaml

Troubleshooting

Issue: Pods stuck in Pending state Solution: Check PersistentVolume provisioning or resource constraints

Issue: HPA not scaling pods Solution: Verify metrics-server is enabled (minikube addons enable metrics-server)

Issue: Cannot access application Solution: Ensure service is properly configured and use minikube service quiz-app-service

References

• Kubernetes Documentation
• Minikube Documentation
• Flask Documentation