exam files

sk1/README.md

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+# Calculator Web Application on Azure Kubernetes Service (AKS)
+
+---
+
+
+##Application Description
+This project is a simple web-based calculator that performs basic mathematical operations.
+It allows users to calculate expressions and save the results. A "Show History" button displays previously saved calculations.
+
+Built with:
+
+- Frontend: HTML/CSS/JavaScript served via Nginx
+
+- Backend: Flask (Python) application connected to a PostgreSQL database
+
+- Database: PostgreSQL 15
+
+---
+
+##Public Cloud Environment
+- Provider: Microsoft Azure
+
+- Service Used: Azure Kubernetes Service (AKS)
+
+- Certificate Issuer: cert-manager with Let's Encrypt
+
+- Domain: https://aliscloudwork.tech
+
+---
+
+
+##Kubernetes and Cloud Components
+- Deployments:
+	- Frontend Deployment (Nginx server)
+	- Backend Deployment (Flask server)
+	- PostgreSQL Deployment (Database server)
+
+- Services: 
+	- Frontend Service (ClusterIP)
+	- Backend Service (ClusterIP)
+	- PostgreSQL Service (ClusterIP)
+	- Ingress Controller Service (LoadBalancer)
+
+- Ingress:
+	- Ingress resource used to route traffic and enable HTTPS
+
+- Persistent Volume:
+	- PostgreSQL database uses a Persistent Volume Claim (PVC) for data persistence
+
+- Certificate Management:
+	- cert-manager with Let's Encrypt to generate HTTPS certificates automatically
+
+---
+
+
+##Files Included
+
+- prepare-app.sh: Script to deploy all Kubernetes objects and services automatically
+
+- remove-app.sh: Script to delete all Kubernetes objects and services
+
+- kubi/*.yaml: Kubernetes deployment, service, ingress, PVC configuration files
+
+- backend/Dockerfile: Dockerfile for the Flask backend application
+
+- frontend/Dockerfile: Dockerfile for the Nginx frontend application
+
+- frontend/default.conf: Nginx configuration file for routing
+
+- README.md: This documentation file
+
+---
+
+
+##How to View and Use the Application
+Open a web browser and visit: https://aliscloudwork.tech
+
+Use the calculator to perform operations.
+
+Click the "Show History" button to view saved calculations.
+
+---
+
+##Running Scripts
+
+- To deploy the application:
+	- ```bash prepare-app.sh```
+- To delete the application:
+	- ```bash remove-app.sh```
+
+---
+
+
+##External Sources and Tools Used
+- DockerHub for container images
+
+- Let's Encrypt for SSL certificates
+
+- cert-manager for Kubernetes certificate automation
+
+- Azure CLI for AKS management
+
+- Official documentation for Nginx, Flask, Kubernetes YAML syntax
+
+---
+
+##Final Notes
+- HTTPS is fully functional.
+
+- Kubernetes ensures all components are modular and recover automatically.
+
+- Database uses persistent storage for calculation history.

sk1/backend/Dockerfile

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+FROM python:3.10-slim
+
+WORKDIR /app
+
+COPY app.py .
+
+RUN pip install Flask flask_sqlalchemy psycopg2-binary flask-cors
+
+CMD ["python", "app.py"]

sk1/backend/app.py

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+from flask import Flask, request, jsonify
+from flask_sqlalchemy import SQLAlchemy
+from flask_cors import CORS
+
+app = Flask(__name__)
+CORS(app, resources={r"/*": {"origins": "*"}})
+
+app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://postgres:yourpassword@postgres-service:5432/calculator'
+app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
+
+db = SQLAlchemy(app)
+
+class Calculation(db.Model):
+    id = db.Column(db.Integer, primary_key=True)
+    expression = db.Column(db.String(100))
+    result = db.Column(db.String(100))
+
+with app.app_context():
+    db.create_all()
+
+@app.route('/save', methods=['POST'])
+def save_calc():
+    data = request.json
+    calc = Calculation(expression=data['expression'], result=data['result'])
+    db.session.add(calc)
+    db.session.commit()
+    return jsonify({'message': 'Saved'}), 201
+
+@app.route('/history', methods=['GET'])
+def history():
+    calcs = Calculation.query.all()
+    return jsonify([{'expression': c.expression, 'result': c.result} for c in calcs])
+
+if __name__ == '__main__':
+    app.run(host='0.0.0.0', port=5000)

sk1/cluster-issuer.yaml

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+apiVersion: cert-manager.io/v1
+kind: ClusterIssuer
+metadata:
+  name: letsencrypt-prod
+spec:
+  acme:
+    server: https://acme-v02.api.letsencrypt.org/directory
+    email: muhammed.tariq.ali.razvi@student.tuke.sk
+    privateKeySecretRef:
+      name: letsencrypt-prod
+    solvers:
+    - http01:
+        ingress:
+          class: nginx

sk1/default-backend.yaml

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+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: default-backend
+  namespace: default
+  annotations:
+    kubernetes.io/ingress.class: nginx
+spec:
+  rules:
+  - http:
+      paths:
+      - pathType: Prefix
+        path: /
+        backend:
+          service:
+            name: frontend
+            port:
+              number: 80

sk1/frontend/Dockerfile

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+# Use official Nginx Alpine image
+FROM nginx:alpine
+
+# Copy static files
+COPY index.html /usr/share/nginx/html/
+COPY style.css /usr/share/nginx/html/
+COPY script.js /usr/share/nginx/html/
+
+# Copy nginx configuration
+COPY default.conf /etc/nginx/conf.d/default.conf

sk1/frontend/default.conf

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+server {
+  listen 80;
+
+  location / {
+    root /usr/share/nginx/html;
+    index index.html;
+    try_files $uri $uri/ =404;
+  }
+
+  location /history {
+    proxy_pass http://backend:5000;
+  }
+
+  location /save {
+    proxy_pass http://backend:5000;
+  }
+}

sk1/frontend/index.html

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+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1" />
+  <title>Calculator</title>
+  <link rel="stylesheet" href="style.css" />
+</head>
+<body>
+  <div id="calculator">
+    <input type="text" id="display" readonly />
+    <div id="buttons">
+      <button class="num">7</button>
+      <button class="num">8</button>
+      <button class="num">9</button>
+      <button class="op">/</button>
+      <button class="num">4</button>
+      <button class="num">5</button>
+      <button class="num">6</button>
+      <button class="op">*</button>
+      <button class="num">1</button>
+      <button class="num">2</button>
+      <button class="num">3</button>
+      <button class="op">-</button>
+      <button class="num">0</button>
+      <button id="clear">C</button>
+      <button id="equals">=</button>
+      <button class="op">+</button>
+    </div>
+    <button id="history">Show History</button>
+    <ul id="history-list"></ul>
+  </div>
+
+  <script src="script.js"></script>
+</body>
+</html>
+

sk1/frontend/script.js

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+const display = document.getElementById('display');
+const buttons = document.querySelectorAll('#buttons button');
+const historyList = document.getElementById('history-list');
+const historyBtn = document.getElementById('history');
+
+let expression = '';
+
+buttons.forEach(button => {
+  button.addEventListener('click', () => {
+    if (button.id === 'clear') {
+      expression = '';
+      display.value = '';
+    } else if (button.id === 'equals') {
+      try {
+        const result = eval(expression);
+        display.value = result;
+        sendToBackend(expression, result);
+        expression = result.toString();
+      } catch (e) {
+        display.value = 'Error';
+        expression = '';
+      }
+    } else {
+      expression += button.textContent;
+      display.value = expression;
+    }
+  });
+});
+
+historyBtn.addEventListener('click', () => {
+  fetch('http://aliscloudwork.tech/history')  // Kubernetes DNS for backend service
+    .then(res => res.json())
+    .then(data => {
+      historyList.innerHTML = '';
+      data.forEach(item => {
+        const li = document.createElement('li');
+        li.textContent = `${item.expression} = ${item.result}`;
+        historyList.appendChild(li);
+      });
+    })
+    .catch(err => alert('Failed to load history'));
+});
+
+function sendToBackend(expr, res) {
+  fetch('http://aliscloudwork.tech/save', {
+    method: 'POST',
+    headers: {'Content-Type': 'application/json'},
+    body: JSON.stringify({expression: expr, result: res})
+  }).catch(err => console.log('Failed to save:', err));
+}

sk1/frontend/style.css

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+body {
+  font-family: Arial, sans-serif;
+  display: flex;
+  justify-content: center;
+  padding: 20px;
+}
+
+#calculator {
+  border: 2px solid #333;
+  padding: 10px;
+  width: 300px;
+}
+
+#display {
+  width: 100%;
+  height: 40px;
+  font-size: 1.5em;
+  margin-bottom: 10px;
+  text-align: right;
+  padding-right: 10px;
+}
+
+#buttons button {
+  width: 22%;
+  height: 40px;
+  margin: 3px 1%;
+  font-size: 1.2em;
+}
+
+#history-list {
+  margin-top: 10px;
+  list-style-type: none;
+  padding-left: 0;
+  max-height: 150px;
+  overflow-y: auto;
+  border-top: 1px solid #ccc;
+}
+

sk1/ingress-svc.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  annotations:
+    kubectl.kubernetes.io/last-applied-configuration: |
+      {"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"app.kubernetes.io/component":"controller","app.kubernetes.io/instance":"ingress-nginx","app.kubernetes.io/name":"ingress-nginx","app.kubernetes.io/part-of":"ingress-nginx","app.kubernetes.io/version":"1.12.1"},"name":"ingress-nginx-controller","namespace":"ingress-nginx"},"spec":{"externalTrafficPolicy":"Local","ipFamilies":["IPv4"],"ipFamilyPolicy":"SingleStack","ports":[{"appProtocol":"http","name":"http","port":80,"protocol":"TCP","targetPort":"http"},{"appProtocol":"https","name":"https","port":443,"protocol":"TCP","targetPort":"https"}],"selector":{"app.kubernetes.io/component":"controller","app.kubernetes.io/instance":"ingress-nginx","app.kubernetes.io/name":"ingress-nginx"},"type":"LoadBalancer"}}
+  creationTimestamp: "2025-04-28T13:26:46Z"
+  finalizers:
+  - service.kubernetes.io/load-balancer-cleanup
+  labels:
+    app.kubernetes.io/component: controller
+    app.kubernetes.io/instance: ingress-nginx
+    app.kubernetes.io/name: ingress-nginx
+    app.kubernetes.io/part-of: ingress-nginx
+    app.kubernetes.io/version: 1.12.1
+  name: ingress-nginx-controller
+  namespace: ingress-nginx
+  resourceVersion: "54668"
+  uid: 346026d8-8939-400c-985e-c63915980d81
+spec:
+  allocateLoadBalancerNodePorts: true
+  clusterIP: 10.0.10.162
+  clusterIPs:
+  - 10.0.10.162
+  externalTrafficPolicy: Local
+  healthCheckNodePort: 31025
+  internalTrafficPolicy: Cluster
+  ipFamilies:
+  - IPv4
+  ipFamilyPolicy: SingleStack
+  ports:
+  - name: http
+    port: 80
+    protocol: TCP
+    targetPort: 80
+  - name: https
+    port: 443
+    protocol: TCP
+    targetPort: 443
+  selector:
+    app.kubernetes.io/component: controller
+    app.kubernetes.io/instance: ingress-nginx
+    app.kubernetes.io/name: ingress-nginx
+  sessionAffinity: None
+  type: LoadBalancer

sk1/kubi/backend-deployment.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: backend
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: backend
+  template:
+    metadata:
+      labels:
+        app: backend
+    spec:
+      containers:
+      - name: backend
+        image: ali0313/backend:latest
+        ports:
+        - containerPort: 5000

sk1/kubi/backend-service.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: backend
+spec:
+  selector:
+    app: backend
+  ports:
+  - port: 5000
+    targetPort: 5000

sk1/kubi/frontend-deployment.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: frontend
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: frontend
+  template:
+    metadata:
+      labels:
+        app: frontend
+    spec:
+      containers:
+      - name: frontend
+        image: ali0313/frontend:latest
+        ports:
+        - containerPort: 80

sk1/kubi/frontend-service.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: frontend
+spec:
+  selector:
+    app: frontend
+  ports:
+  - protocol: TCP
+    port: 80
+    targetPort: 80
+  type: ClusterIP

sk1/kubi/ingress.yaml

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+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: app-ingress
+  annotations:
+    cert-manager.io/cluster-issuer: "letsencrypt-prod"
+spec:
+  ingressClassName: nginx
+  tls:
+  - hosts:
+    - aliscloudwork.tech
+    secretName: tls-secret
+  rules:
+  - host: aliscloudwork.tech
+    http:
+      paths:
+      - path: /
+        pathType: Prefix
+        backend:
+          service:
+            name: frontend
+            port:
+              number: 80

sk1/kubi/postgres-deployment.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: postgres
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: postgres
+  template:
+    metadata:
+      labels:
+        app: postgres
+    spec:
+      containers:
+      - name: postgres
+        image: postgres:15
+        env:
+          - name: POSTGRES_DB
+            value: calculator
+          - name: POSTGRES_USER
+            value: postgres
+          - name: POSTGRES_PASSWORD
+            value: yourpassword
+          - name: PGDATA
+            value: /var/lib/postgresql/data/pgdata  # ← Keep this
+        ports:
+        - containerPort: 5432
+        volumeMounts:
+        - mountPath: /var/lib/postgresql/data     # ← CHANGE HERE (one level up)
+          name: pgdata
+      volumes:
+      - name: pgdata
+        persistentVolumeClaim:
+          claimName: pgdata-pvc

sk1/kubi/postgres-service.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: postgres-service
+spec:
+  selector:
+    app: postgres
+  ports:
+  - port: 5432
+    targetPort: 5432
+

sk1/kubi/pvc.yaml

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+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: pgdata-pvc
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 1Gi

sk1/prepare-app.sh

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+#!/bin/bash
+
+echo "Starting application deployment..."
+# Apply Persistent Volume Claim
+kubectl apply -f kubi/pvc.yaml
+
+# Deploy PostgreSQL
+kubectl apply -f kubi/postgres-deployment.yaml
+kubectl apply -f kubi/postgres-service.yaml
+
+# Deploy Backend
+kubectl apply -f kubi/backend-deployment.yaml
+kubectl apply -f kubi/backend-service.yaml
+
+# Deploy Frontend
+kubectl apply -f kubi/frontend-deployment.yaml
+kubectl apply -f kubi/frontend-service.yaml
+
+
+# Apply cert-manager ClusterIssuer
+kubectl apply -f cluster-issuer.yaml
+
+# Apply Ingress
+kubectl apply -f kubi/ingress.yaml
+
+echo "Deployment completed successfully!"

sk1/remove-app.sh

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+#!/bin/bash
+
+echo "Starting application removal..."
+
+# Delete Ingress
+kubectl delete -f kubi/ingress.yaml
+
+# Delete cert-manager ClusterIssuer
+kubectl delete -f cluster-issuer.yaml
+
+# Delete Frontend
+kubectl delete -f kubi/frontend-service.yaml
+kubectl delete -f kubi/frontend-deployment.yaml
+
+# Delete Backend
+kubectl delete -f kubi/backend-service.yaml
+kubectl delete -f kubi/backend-deployment.yaml
+
+# Delete PostgreSQL
+kubectl delete -f kubi/postgres-service.yaml
+kubectl delete -f kubi/postgres-deployment.yaml
+
+# Delete Persistent Volume Claim
+kubectl delete -f kubi/pvc.yaml
+
+echo "Application resources removed successfully!"