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z2/Dockerfile

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+FROM python:3.9-slim
+
+WORKDIR /app
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY app.py .
+
+ENV FLASK_APP=app.py
+ENV FLASK_RUN_HOST=0.0.0.0
+ENV FLASK_RUN_PORT=5000
+
+EXPOSE 5000
+
+CMD ["flask", "run"]

z2/README.md

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+# Blog Application with Kubernetes
+
+This project deploys a simple blog application with Flask and PostgreSQL on Kubernetes.
+
+## Application Features
+
+- Create and publish blog articles with title and content
+- View all articles in a responsive interface
+- Delete articles with a single click
+- Persistent storage for database content
+
+## Architecture
+
+The application consists of:
+- Flask web application for creating and deleting blog articles
+- PostgreSQL database to store the articles
+- Kubernetes deployment for orchestration and scaling
+
+## Technologies Used
+
+- **Frontend**: HTML, CSS, Flask Templates
+- **Backend**: Python, Flask
+- **Database**: PostgreSQL
+- **Container**: Docker
+- **Orchestration**: Kubernetes, Minikube
+
+## Deployment Instructions
+
+### Prerequisites
+- Docker
+- Minikube
+- kubectl
+
+### Step 1: Preparation
+Run the preparation script to create the namespace and build the Docker image:
+```
+chmod +x prepare-app.sh
+./prepare-app.sh
+```
+
+### Step 2: Deployment
+Launch the application with:
+```
+chmod +x start-app.sh
+./start-app.sh
+```
+
+### Step 3: Access the Application
+Get the application URL with:
+```
+minikube service blog-app-service -n myapp-namespace --url
+```
+Open this URL in your browser to access the blog application.
+
+### Step 4: Shutdown
+When finished, clean up all resources with:
+```
+chmod +x stop-app.sh
+./stop-app.sh
+```

z2/app.py

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+from flask import Flask, request, jsonify
+import os
+import psycopg2
+import time
+
+app = Flask(__name__)
+
+# Database Configuration
+db_host = os.environ.get("DB_HOST", "blog-db-service")
+db_name = os.environ.get("POSTGRES_DB", "blogdb")  
+db_user = os.environ.get("POSTGRES_USER", "admin") 
+db_password = os.environ.get("POSTGRES_PASSWORD", "password")
+
+def get_db_connection():
+    return psycopg2.connect(host=db_host, database=db_name, user=db_user, password=db_password)
+
+def create_table():
+    max_retries = 10
+    retry_delay = 5  # seconds
+    
+    for attempt in range(max_retries):
+        try:
+            print(f"Attempt {attempt+1}/{max_retries} to connect to database...")
+            conn = get_db_connection()
+            cur = conn.cursor()
+            cur.execute('''
+                CREATE TABLE IF NOT EXISTS articles (
+                    id SERIAL PRIMARY KEY,
+                    title TEXT NOT NULL,
+                    content TEXT NOT NULL
+                )
+            ''')
+            conn.commit()
+            cur.close()
+            conn.close()
+            print("Table 'articles' created successfully")
+            return True
+        except Exception as e:
+            print(f"Database connection attempt {attempt+1}/{max_retries} failed: {e}")
+            if attempt < max_retries - 1:
+                print(f"Retrying in {retry_delay} seconds...")
+                time.sleep(retry_delay)
+    
+    print("Failed to create table after multiple attempts")
+    return False
+
+# Initialize the variable at startup
+table_created = False
+
+@app.route("/", methods=["GET", "POST"])
+def index():
+    global table_created
+    
+    # If the table is not yet created, try to create it
+    if not table_created:
+        table_created = create_table()
+    
+    # Check if the table has been created before continuing
+    if not table_created:
+        return "Database connection failed. Please try again later.", 500
+    
+    try:
+        conn = get_db_connection()
+        cur = conn.cursor()
+        
+        if request.method == "POST":
+            title = request.form.get("title")
+            content = request.form.get("content")
+            if title and content:
+                cur.execute("INSERT INTO articles (title, content) VALUES (%s, %s)", (title, content))
+                conn.commit()
+        
+        cur.execute("SELECT * FROM articles ORDER BY id DESC")
+        articles = cur.fetchall()
+        cur.close()
+        conn.close()
+        
+        return f"""
+        <html>
+        <head>
+            <title>My Blog</title>
+            <style>
+                body {{ font-family: 'Poppins', sans-serif; background-color: #f5f5f5; color: #333; margin: 0; padding: 0; }}
+                .container {{ max-width: 1100px; margin: 50px auto; background: #6a0dad; padding: 30px; border-radius: 10px; box-shadow: 0 0 10px rgba(0, 0, 0, 0.1); display: flex; gap: 20px; }}
+                .form-container, .articles-container {{ flex: 1; background: #ffffff; padding: 20px; border-radius: 10px; box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1); }}
+                h1{{ text-align: center; color: #6a0dad; font-size: 30px; }}
+                form {{ display: flex; flex-direction: column; gap: 10px; align-items: center; }}
+                input, textarea {{ width: 90%; padding: 14px; border: 1px solid #ccc; border-radius: 5px; background: #fff; color: #333; font-size: 18px; }}
+                button {{ background-color: #6a0dad; color: white; border: none; padding: 12px 25px; cursor: pointer; border-radius: 5px; transition: background 0.3s; font-size: 20px; }}
+                button:hover {{ background-color: #5a0dad; }}
+                .articles-container {{ display: flex; flex-direction: column; gap: 15px; }}
+                .article {{ background: #e0e0e0; padding: 20px; border-radius: 5px; box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1); position: relative; }}
+                .article h3 {{ margin: 0; color: #333; font-size: 22px; }}
+                .article p {{ margin: 10px 0; color: #555; font-size: 18px; }}
+                .delete-form {{ position: absolute; top: 10px; right: 10px; }}
+                .delete-button {{ background-color: #ff5555; padding: 8px 12px; font-size: 14px; border-radius: 5px; }}
+                .delete-button:hover {{ background-color: #cc4444; }}
+            </style>
+        </head>
+        <body>
+            <div class="container">
+                <div class="form-container">
+                    <h1>My Blog</h1>
+                    <form method="post">
+                        <input type="text" name="title" placeholder="Title" required>
+                        <textarea name="content" placeholder="Content" required></textarea>
+                        <button type="submit">Add Article</button>
+                    </form>
+                </div>
+                <div class="articles-container">
+                    <h1>Articles</h1>
+                    {''.join(f'<div class="article"><h3>{a[1]}</h3><p>{a[2]}</p><form method="post" action="/delete/{a[0]}" class="delete-form"><button type="submit" class="delete-button">Delete</button></form></div>' for a in articles)}
+                </div>
+            </div>
+        </body>
+        </html>
+        """
+    except Exception as e:
+        return f"An error occurred: {str(e)}", 500
+
+@app.route("/delete/<int:article_id>", methods=["POST"])
+def delete_article(article_id):
+    try:
+        conn = get_db_connection()
+        cur = conn.cursor()
+        cur.execute("DELETE FROM articles WHERE id = %s", (article_id,))
+        conn.commit()
+        cur.close()
+        conn.close()
+        return "<script>window.location.href='/'</script>"
+    except Exception as e:
+        return f"An error occurred while deleting: {str(e)}", 500
+
+if __name__ == "__main__":
+    create_table() 
+    app.run(host="0.0.0.0", port=5000)

z2/deployment.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: blog-app
+  namespace: myapp-namespace
+  labels:
+    app: blog
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: blog
+  template:
+    metadata:
+      labels:
+        app: blog
+    spec:
+      containers:
+      - name: blog-app
+        image: blog-app:latest
+        imagePullPolicy: Never
+        ports:
+        - containerPort: 5000
+        env:
+        - name: DB_HOST
+          value: "blog-db-service"
+        - name: POSTGRES_DB
+          value: "blogdb"
+        - name: POSTGRES_USER
+          value: "admin"
+        - name: POSTGRES_PASSWORD
+          value: "password"

z2/namespace.yaml

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+apiVersion: v1
+kind: Namespace
+metadata:
+  name: myapp-namespace

z2/prepare-app.sh

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+#!/bin/bash
+
+# Create the namespace
+kubectl apply -f namespace.yaml
+
+# Build the Docker image
+docker build -t blog-app:latest .
+
+# Ensure minikube uses the local image
+eval $(minikube docker-env)
+docker build -t blog-app:latest .
+
+# Start Minikube if it's not already running
+if ! minikube status | grep -q "Running"; then
+  minikube start
+fi
+
+echo "Preparation complete. You can now run ./start-app.sh"

z2/requirements.txt

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+Flask
+psycopg2-binary
+requests

z2/service.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: blog-app-service
+  namespace: myapp-namespace
+spec:
+  selector:
+    app: blog
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 5000
+      nodePort: 30080
+  type: NodePort
+
+---
+
+apiVersion: v1
+kind: Service
+metadata:
+  name: blog-db-service
+  namespace: myapp-namespace
+spec:
+  selector:
+    app: blog-db
+  ports:
+    - protocol: TCP
+      port: 5432
+      targetPort: 5432
+  type: ClusterIP

z2/start-app.sh

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+#!/bin/bash
+
+# Create the namespace if it doesn't already exist
+kubectl apply -f namespace.yaml
+
+# Create the statefulset for the database
+kubectl apply -f statefulset.yaml
+
+# Create the deployment for the application
+kubectl apply -f deployment.yaml
+
+# Create the services
+kubectl apply -f service.yaml
+
+# Display created resources
+echo "Resources created:"
+kubectl get all -n myapp-namespace

z2/statefulset.yaml

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+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: blog-db
+  namespace: myapp-namespace
+spec:
+  serviceName: "blog-db-service"
+  replicas: 1
+  selector:
+    matchLabels:
+      app: blog-db
+  template:
+    metadata:
+      labels:
+        app: blog-db
+    spec:
+      containers:
+      - name: postgres
+        image: postgres:13
+        ports:
+        - containerPort: 5432
+        env:
+        - name: POSTGRES_DB
+          value: "blogdb"
+        - name: POSTGRES_USER
+          value: "admin"
+        - name: POSTGRES_PASSWORD
+          value: "password"
+        volumeMounts:
+        - name: postgres-storage
+          mountPath: /var/lib/postgresql/data
+          subPath: pgdata 
+  volumeClaimTemplates:
+  - metadata:
+      name: postgres-storage
+    spec:
+      accessModes: ["ReadWriteOnce"]
+      resources:
+        requests:
+          storage: 1Gi

z2/stop-app.sh

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+#!/bin/bash
+
+# Delete services
+kubectl delete -f service.yaml
+
+# Delete deployment
+kubectl delete -f deployment.yaml
+
+# Delete statefulset
+kubectl delete -f statefulset.yaml
+
+# Delete namespace
+kubectl delete -f namespace.yaml
+
+echo "All resources have been deleted."