SA2 Kubernetes Project completed

.dockerignore

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+node_modules
+kube

.gitignore

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+node_modules
+*/public/uploads
+
+*.tar
+data/

Dockerfile

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+FROM node:18.0-slim
+COPY . .
+RUN npm install
+CMD [ "node", "index.js" ]

README.md

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+
+SA II Project: Building and Scaling expressjs-mongodb-app on Kubernetes
+Project Overview
+Welcome to the documentation of the System Administration II course at TSBE. This project focuses on the installation and scaling of the expressjs-mongodb-app on a Kubernetes cluster.
+
+Project Goals
+The primary objectives of this project are to set up and configure a Kubernetes cluster with the following key features:
+
+Scalability: Utilizing Kubernetes orchestration for seamless scaling.
+Persistent Storage: Implementing containers with persistent storage, specifically for a MongoDB Database.
+Container Networking: Establishing effective container networking with port forwarding to enable external access.
+Security: Configuring a secure environment to minimize potential security risks.
+Used Ports:
+3000: expressjs-app
+27017: MongoDB
+
+Platform & Limitations
+The following virtual platform is hosted by the school to execute the project:
+
+vmKL1
+The vmKL1 is the management machine used to set up, administer, and access the Kubernetes cluster.
+
+VM Specs:
+
+OS: Kali GNU/Linux
+Kernel: Linux 6.5.0-kali3-amd64
+CPU: 2 vCPUs
+RAM: 16 GB
+Storage: /dev/sda 35 GB
+Network: Access to vmLM1 & Internet
+IP: 192.168.110.70
+Installed Software:
+
+vscode
+vmLM1
+
+The vmLM1 is the Kubernetes host itself. It will act as Control Plane (Master Node) & Data Plane (Worker Node).
+VM Specs:
+OS: Ubuntu 22.04.3 LTS
+Kernel: Linux
+CPU: 4 vCPUs
+RAM: 12 GB
+Storage: /dev/sda 16 GB
+Network: Access to vmKL1 & Internet
+IP: 192.168.110.60
+Installed Software:
+minikube version: v1.32.0
+The container network is set up in a way that only necessary communication is allowed. UFW is active and configured. Open ports to the Kubernetes Node (vmLM1):
+
+22/TCP -> SSH
+443/TCP -> Kubernetes API
+30703/TCP -> express-mongodb-app
+8001/TCP -> Kubernetes Dashboard
+31185/TCP -> Argocd (optional)
+As far as the container network goes, only pods that need external access are configured with NodePort. All other pods are configured with Cluster IP for Kubernetes internal-only communication.
+
+Manual Setup Guide
+vmKL1:
+# Update the System
+sudo apt update -y
+sudo apt upgrade -y
+
+vmLM1:
+# Port forward , Enable & open necessary ports on the server firewall
+sudo ufw allow 22/tcp
+sudo ufw allow 443/tcp
+sudo ufw allow 80
+sudo ufw allow 8001 # for minikube dashboard
+sudo ufw allow 30703 # for express-mongodb-app
+sudo ufw allow 31185 # for argocd (optional)
+sudo ufw enable
+
+# Enable SSH access by uncommenting the following line in /etc/ssh/sshd_config
+Port 22
+
+# Restart sshd
+sudo systemctl restart sshd
+
+# Update the System
+sudo apt update -y
+sudo apt upgrade -y
+
+# Install Docker
+sudo apt install docker.io
+docker --version # Check Docker version
+
+# Download Minikube
+curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
+sudo install minikube-linux-amd64 /usr/local/bin/minikube
+minikube version # Check Minikube version
+
+# Install Kubectl
+sudo snap install kubectl --classic
+kubectl version # Check Kubectl version
+
+# Start Minikube with Docker driver
+minikube start --driver=docker
+sudo usermod -aG docker $USER && newgrp docker
+minikube node add —worker
+kubectl label node <node_name> node-role.kubernetes.io/worker=worker
+kubectl get nodes 
+
+# Update local apt cache
+sudo apt update
+
+# Create a namespace for the app
+kubectl create namespace nodejs-mongodb-app
+
+# Create a project folder for deployment
+mkdir ~/kube

index.js

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+const path = require('path')
+const express = require('express')
+const MongoClient = require('mongodb').MongoClient
+const multer = require('multer')
+const { marked } = require('marked')
+
+const app = express()
+const port = process.env.PORT || 3000
+const mongoURL = process.env.MONGO_URL || 'mongodb://localhost:27017/dev'
+
+async function initMongo() {
+  console.log('Initialising MongoDB...')
+  let success = false
+  while (!success) {
+    try {
+      client = await MongoClient.connect(mongoURL, {
+        useNewUrlParser: true,
+        useUnifiedTopology: true,
+      })
+      success = true
+    } catch {
+      console.log('Error connecting to MongoDB, retrying in 1 second')
+      await new Promise(resolve => setTimeout(resolve, 1000))
+    }
+  }
+  console.log('MongoDB initialised')
+  return client.db(client.s.options.dbName).collection('notes')
+}
+
+async function start() {
+  const db = await initMongo()
+
+  app.set('view engine', 'pug')
+  app.set('views', path.join(__dirname, 'views'))
+  app.use(express.static(path.join(__dirname, 'public')))
+
+  app.get('/', async (req, res) => {
+    res.render('index', { notes: await retrieveNotes(db) })
+  })
+
+  app.post(
+    '/note',
+    multer({ dest: path.join(__dirname, 'public/uploads/') }).single('image'),
+    async (req, res) => {
+      if (!req.body.upload && req.body.description) {
+        await saveNote(db, { description: req.body.description })
+        res.redirect('/')
+      } else if (req.body.upload && req.file) {
+        const link = `/uploads/${encodeURIComponent(req.file.filename)}`
+        res.render('index', {
+          content: `${req.body.description} ![](${link})`,
+          notes: await retrieveNotes(db),
+        }) 
+      }
+    },
+  )
+
+  app.listen(port, () => {
+    console.log(`App listening on http://localhost:${port}`)
+  })
+}
+
+async function saveNote(db, note) {
+  await db.insertOne(note)
+}
+
+async function retrieveNotes(db) {
+  const notes = await db.find().toArray()
+  const sortedNotes = notes.reverse()
+  return sortedNotes.map(it => ({ ...it, description: marked(it.description) }))
+}
+
+start()

kube/mongo-config.yaml

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+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: mongo-config
+data:
+  MONGO_URL: "mongodb://mongo:27017/dev"

kube/mongo-hpa.yaml

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+apiVersion: autoscaling/v1
+kind: HorizontalPodAutoscaler
+metadata:
+  name: mongo-hpa
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: mongo
+  minReplicas: 1
+  maxReplicas: 5
+  targetCPUUtilizationPercentage: 50

kube/mongo.yaml

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+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: mongo-pvc
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 256Mi
+
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: mongo
+spec:
+  selector:
+    app: mongo
+  ports:
+    - port: 27017
+      targetPort: 27017
+
+---
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: mongo
+spec:
+  serviceName: "mongo"
+  replicas: 1 
+  selector:
+    matchLabels:
+      app: mongo
+  template:
+    metadata:
+      labels:
+        app: mongo
+    spec:
+      containers:
+        - name: mongo
+          image: mongo:6.0.2-focal
+          ports:
+            - containerPort: 27017
+          volumeMounts:
+            - name: storage
+              mountPath: /data/db
+          resources:
+            requests:
+              memory: "512Mi"
+              cpu: "250m"
+            limits:
+              memory: "1Gi"
+              cpu: "500m"
+
+  volumeClaimTemplates:
+  - metadata:
+      name: storage
+    spec:
+      accessModes:
+        - ReadWriteOnce
+      resources:
+        requests:
+          storage: 256Mi

kube/server-hpa.yaml

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+apiVersion: autoscaling/v1
+kind: HorizontalPodAutoscaler
+metadata:
+  name: server-hpa
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: server
+  minReplicas: 1
+  maxReplicas: 10
+  targetCPUUtilizationPercentage: 50

kube/server.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: server
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: server
+  template:
+    metadata:
+      labels:
+        app: server
+    spec: 
+      containers:
+        - name: server
+          image: yavuzozbay/nodeserver:2.0.0
+          ports:
+            - containerPort: 3000
+          env:
+            - name: MONGO_URL
+              valueFrom:
+                configMapKeyRef:
+                  name: mongo-config
+                  key: MONGO_URL
+          imagePullPolicy: Always
+          resources:
+            requests:
+              memory: "128Mi"
+              cpu: "100m"
+            limits:
+              memory: "264Mi"
+              cpu: "250m"
+
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: server-service
+spec:
+  selector:
+    app: server
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 3000
+  type: NodePort