A simple Flask-based calculator web application containerized using Docker and deployed using Kubernetes (Minikube).
This project demonstrates a basic DevOps workflow including application development, containerization, and deployment.

This application allows users to enter mathematical expressions such as:

10 + 5

and instantly receive the calculated result.

The goal of this project is to demonstrate how a simple application can be deployed using modern DevOps tools.

The project includes:

• Python backend development using Flask
• Web interface for user interaction
• REST API for performing calculations
• Docker containerization
• Kubernetes deployment using Minikube
• Source code management using Git and GitHub

• 🐍 Python – Backend programming
• 🌶 Flask – Web application framework
• 🔐 Flask-CORS – Cross-origin request support
• 🐳 Docker – Containerization
• ☸ Kubernetes – Container orchestration
• 🧪 Minikube – Local Kubernetes cluster
• 🔧 Git – Version control
• 🌍 GitHub – Code hosting and project management

• Web-based calculator interface
• REST API for performing calculations
• Supports arithmetic operations:

Addition (+)
Subtraction (-)
Multiplication (*)
Division (/)

• Error handling for invalid expressions
• Division-by-zero protection
• Containerized using Docker
• Deployable using Kubernetes

flask-calculator-devops-project
│
├── app.py
├── Dockerfile
├── requirements.txt
├── deployment.yaml
├── service.yaml
├── .gitignore
└── README.md

The application provides a simple web interface where users can enter expressions such as:

10 + 5
20 * 3
15 - 7
10 / 2

The result is displayed immediately on the screen.

GET /

Displays the calculator web interface.

POST /calculate

Example request:

{
  "expression": "10 + 5"
}

Example response:

{
  "result": 15
}

Example error response:

{
  "error": "Division by zero is not allowed"
}

Install dependencies:

pip install -r requirements.txt

Run the Flask application:

python app.py

Open browser:

http://localhost:5000

Build Docker image:

docker build -t calculator .

Run Docker container:

docker run -p 5000:5000 calculator

Access application:

http://localhost:5000

Start Minikube:

minikube start

Deploy application:

kubectl apply -f deployment.yaml

Create service:

kubectl apply -f service.yaml

Check running pods:

kubectl get pods

Access application:

minikube service calculator-service

User Browser
      ↓
Flask Calculator Application
      ↓
Docker Container
      ↓
Docker Hub
      ↓
Kubernetes Deployment
      ↓
Minikube Cluster

• Add CI/CD pipeline using GitHub Actions
• Deploy application to cloud Kubernetes clusters (AWS EKS / GCP GKE)
• Add advanced UI using React
• Add automated testing
• Implement monitoring using Prometheus and Grafana

Manjushree Bhandary

GitHub Repository:

https://github.com/manju0301/flask-calculator-devops-project

• Python Backend Development
• Docker Containerization
• Kubernetes Deployment
• API Development
• Git Version Control
• DevOps Workflow Implementation