100-Days-Of-DevOps-Challenge-KodeKloud

Persistent Volumes in Kubernetes

The Nautilus DevOps team is working on a Kubernetes template to deploy a web application on the cluster. There are some requirements to create/use persistent volumes to store the application code, and the template needs to be designed accordingly. Please find more details below:

• Create a PersistentVolume named as pv-xfusion. Configure the spec as storage class should be manual, set capacity to 3Gi, set access mode to ReadWriteOnce, volume type should be hostPath and set path to /mnt/security (this directory is already created, you might not be able to access it directly, so you need not to worry about it).
• Create a PersistentVolumeClaim named as pvc-xfusion. Configure the spec as storage class should be manual, request 3Gi of the storage, set access mode to ReadWriteOnce.
• Create a pod named as pod-xfusion, mount the persistent volume you created with claim name pvc-xfusion at document root of the web server, the container within the pod should be named as container-xfusion using image httpd with latest tag only (remember to mention the tag i.e httpd:latest).
• Create a node port type service named web-xfusion using node port 30008 to expose the web server running within the pod.

Note: The kubectl utility on jump_host has been configured to work with the kubernetes cluster.

Steps

1. Create a persistent volume k3s-pv.yaml with this content:

    apiVersion: v1
    kind: PersistentVolume
    metadata:
    name: pv-xfusion
    spec:
    capacity:
        storage: 3Gi
    accessModes:
        - ReadWriteOnce
    storageClassName: manual
    hostPath:
        path: /mnt/security
   

   Create the volume:

    kubectl apply -f k3s-pv.yaml
   

2. Create the persistent volume claim k3s-pvc.yaml with this following content:

    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
    name: pvc-xfusion
    spec:
    accessModes:
        - ReadWriteOnce
    resources:
        requests:
        storage: 3Gi
    storageClassName: manual
   

   To create the pvc:

    kubectl k3s-pvc.yaml
   

3. Create the pod k3s-pod.yaml:

    apiVersion: v1
    kind: Pod
    metadata:
    name: pod-xfusion
    labels:
        app: xfusion
    spec:
    containers:
        - name: container-xfusion
        image: httpd:latest
        volumeMounts:
            - name: xfusion-volume
            mountPath: /mnt/security
        resources:
            limits:
            memory: "128Mi"
            cpu: "500m"
            requests:
            memory: "64Mi"
            cpu: "250m"
    volumes:
        - name: xfusion-volume
        persistentVolumeClaim:
            claimName: pvc-xfusion
   

   run the pod

    kubectl apply -f k3s-pod.yaml
   

4. And finally, create the service k3s-svc.yaml:

    apiVersion: v1
    kind: Service
    metadata:
    name: web-xfusion
    labels:
        app: xfusion
    spec:
    type: NodePort
    ports:
        - port: 80
        targetPort: 80
        nodePort: 30008
    selector:
        app: xfusion
   

    kubectl apply -f k3s-svc.yaml
   

5. We can put all in one file k3s-pod.yaml

Good to Know?

Persistent Volumes (PV)

• Purpose: Cluster-wide storage resources
• Lifecycle: Independent of pod lifecycle
• Storage Classes: Different types of storage (SSD, HDD, NFS)
• Access Modes: ReadWriteOnce, ReadOnlyMany, ReadWriteMany

Persistent Volume Claims (PVC)

• Purpose: Request for storage by pods
• Binding: PVC binds to suitable PV
• Dynamic Provisioning: Automatic PV creation
• Storage Classes: Specify storage requirements

Volume Types

• hostPath: Mount directory from host (development only)
• nfs: Network File System
• awsElasticBlockStore: AWS EBS volumes
• gcePersistentDisk: Google Cloud persistent disks
• azureDisk: Azure disk storage

Best Practices

• Storage Classes: Use storage classes for dynamic provisioning
• Backup: Regular backup of persistent data
• Monitoring: Monitor storage usage and performance
• Security: Encrypt sensitive data at rest

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