Project Overview

This project involves setting up a three-tier architecture (Proxy, Backend, Database) on Kubernetes. Each tier is deployed as a Kubernetes Deployment with two replicas for redundancy. All resources are organized under the webapp namespace. The project also integrates Persistent Volume (PV) and Persistent Volume Claim (PVC) for data persistence and a secret for database credentials.

Components

1. Namespace (ns.yaml):

   • A separate namespace, webapp, is used to isolate all resources in the project.

   apiVersion: v1
   kind: Namespace
   metadata:
     name: webapp

2. Backend Deployment (backend-deployment.yaml):

   • This deployment runs two replicas of the backend application.
   • Secret for database credentials (db-secret) is mounted as a volume.
   • An init container pre-configures secrets before the backend container starts.

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: backend-deployment
     namespace: webapp
     labels:
       app: backend-deployment
   spec:
     replicas: 2
     selector:
       matchLabels:
         app: backend
     template:
       metadata:
         labels:
           app: backend
       spec:
         volumes:
         - name: db-password
           secret:
             secretName: db-secret
         - name: pre-install
           emptyDir: {}
         initContainers:
         - name: pre-install
           image: busybox
           command: ['sh', '-c', 'cat /db-secret/db-password >> /run/secrets/db-password']
           volumeMounts:
           - name: db-password
             mountPath: "/db-secret"
           - name: pre-install
             mountPath: "/run/secrets"
         containers:
         - name: backend
           image: omarbanna/backend10:latest
           imagePullPolicy: Never
           ports:
           - containerPort: 8000
           volumeMounts:
           - name: pre-install
             mountPath: "/run/secrets"
           - name: db-password
             mountPath: "/db-secret"

3. Backend Service (backend-service.yaml):

   • A ClusterIP service for the backend to allow internal communication between other pods.

   apiVersion: v1
   kind: Service
   metadata:
     name: backendservice
     namespace: webapp
   spec:
     selector:
       app: backend
     ports:
     - protocol: TCP
       port: 8000
       targetPort: 8000

4. Database Deployment (db-deployment.yaml):

   • Runs a MySQL database with one replica.
   • The database password is sourced from the secret db-secret.
   • Persistent storage is managed using a PVC (my-pvc).

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: database-deployment
     namespace: webapp
     labels:
       app: database-deployment
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: database
     template:
       metadata:
         labels:
           app: database
       spec:
         volumes:
         - name: db-password
           secret:
             secretName: db-secret
         - name: db-data
           persistentVolumeClaim:
             claimName: my-pvc
         containers:
         - name: database
           image: mysql:8.0
           env:
           - name: MYSQL_ROOT_PASSWORD
             valueFrom:
               secretKeyRef:
                 name: db-secret
                 key: db-password
           - name: MYSQL_DATABASE
             value: "example"
           ports:
           - containerPort: 3306
           volumeMounts:
           - name: db-data
             mountPath: "/var/lib/mysql"

5. Database Service (db-service.yaml):

   • A ClusterIP service for the database, allowing internal access to the MySQL instance from other services.

   apiVersion: v1
   kind: Service
   metadata:
     name: db
     namespace: webapp
   spec:
     selector:
       app: database
     ports:
     - protocol: TCP
       port: 3306
       targetPort: 3306

6. Proxy Deployment (proxy-deployment.yaml):

   • Runs the proxy with two replicas.
   • Configured to forward traffic to the backend.

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: proxy-deployment
     namespace: webapp
     labels:
       app: proxy-deployment
   spec:
     replicas: 2
     selector:
       matchLabels:
         app: proxy
     template:
       metadata:
         labels:
           app: proxy
       spec:
         containers:
         - name: proxy
           image: omarbanna/proxy10:latest
           imagePullPolicy: IfNotPresent
           ports:
           - containerPort: 443

7. Proxy Service (proxy-service.yaml):

   • A NodePort service for external access to the proxy, exposing it on port 30002.

   apiVersion: v1
   kind: Service
   metadata:
     name: proxy-service
     namespace: webapp
   spec:
     selector:
       app: proxy
     type: NodePort
     ports:
     - name: https
       protocol: TCP
       port: 443
       targetPort: 443
       nodePort: 30002

8. Persistent Volume (PV.yaml):

   • A 5GB persistent volume for the database storage.

   apiVersion: v1
   kind: PersistentVolume
   metadata:
     name: db-pv
     namespace: webapp
   spec:
     capacity:
       storage: 5Gi
     storageClassName: standard
     accessModes:
     - ReadWriteMany
     persistentVolumeReclaimPolicy: Retain
     hostPath:
       path: "/var/mysql"

9. Persistent Volume Claim (PVC.yaml):

   • A 1GB persistent volume claim used by the MySQL database.

   apiVersion: v1
   kind: PersistentVolumeClaim
   metadata:
     name: my-pvc
     namespace: webapp
   spec:
     accessModes:
     - ReadWriteOnce
     resources:
       requests:
         storage: 1Gi

10. Credentials Volume (credentials-Volume.yaml):

    • The db-credentials.txt secret is mounted in the backend and database deployments, providing secure access to sensitive data.

    apiVersion: v1
    kind: Secret
    metadata:
      name: db-secret
      namespace: webapp
    data:
      db-password: U3Ryb25nUEBzc3cwcmQyMDI0

11.pods testing

Key Considerations

• Namespace Isolation: All resources are contained within the webapp namespace, ensuring isolation.
• Service Communication: The proxy communicates with the backend using the ClusterIP service, while the backend communicates with the database service.
• Data Persistence: The MySQL database uses a persistent volume claim (PVC) to ensure data persistence across pod restarts.
• Secret Management: Sensitive database credentials are stored securely in Kubernetes secrets and mounted into the appropriate pods.