How to Setup Dynamic NFS Provisioning in a Kubernetes Cluster

Dynamic NFS storage provisioning in Kubernetes streamlines the creation and management of NFS volumes for your Kubernetes applications. It eliminates the need for manual intervention or pre-provisioned storage. The NFS provisioner dynamically creates persistent volumes (PVs) and associates them with persistent volume claims (PVCs), making the process more efficient. If you have an external NFS share and want to use it in a pod or deployment, the nfs-subdir-external-provisioner provides a solution for effortlessly setting up a storage class to automate the management of your persistent volumes.

Prerequisites

• Pre-installed Kubernetes Cluster
• A Regular user which has admin rights on the Kubernetes cluster
• Internet Connectivity

Step 1: Installing the NFS Server

sudo apt-get update
sudo apt-get install nfs-common nfs-kernel-server -y

Create a directory to export:

sudo mkdir -p /data/nfs
sudo chown nobody:nogroup /data/nfs
sudo chmod 2770 /data/nfs

Export directory and restart NFS service:

echo -e "/data/nfs\t10.124.0.0/24(rw,sync,no_subtree_check,no_root_squash)" | sudo tee -a /etc/exports

sudo exportfs -av

# Restart and show logs
sudo systemctl restart nfs-kernel-server
sudo systemctl status nfs-kernel-server

Show Export Details:

/sbin/showmount -e 10.124.0.9

Step 2: Install NFS client packages on K8s Nodes

Make sure all your Kubernetes nodes have the NFS client packages installed. On Ubuntu-based nodes, install nfs-common:

sudo apt update
sudo apt install nfs-common -y

Step 3: Install and Configure NFS Client Provisioner

Deploy the NFS Subdir External Provisioner in your Kubernetes cluster to automate the creation and management of NFS-backed Persistent Volumes (PVs) and Persistent Volume Claims (PVCs).

Install Helm3 on Debian/Ubuntu using the following commands:

curl https://baltocdn.com/helm/signing.asc | sudo apt-key add -
sudo apt-get install apt-transport-https --yes
echo "deb https://baltocdn.com/helm/stable/debian/ all main" | sudo tee /etc/apt/sources.list.d/helm-stable-debian.list
sudo apt-get update
sudo apt-get install helm

Add Helm Repository for nfs-subdir-external-provisioner:

helm repo add nfs-subdir-external-provisioner https://kubernetes-sigs.github.io/nfs-subdir-external-provisioner

Install Helm Chart for NFS

helm install nfs-subdir-external-provisioner \
nfs-subdir-external-provisioner/nfs-subdir-external-provisioner \
--set nfs.server=10.124.0.9 \
--set nfs.path=/data/nfs \
--set storageClass.onDelete=true

# Check pods and storage classes:
kubectl get pod
kubectl get sc

NFS dynamic storage class was installed and “nfs-client” storage was created.

Step 4: Dynamic PVC Volume Create Testing:

Now we can test creating dynamic PVC volume.

nfs-pvc.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-pvc
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: nfs-client
  resources:
    requests:
      storage: 5Gi

Create an NGINX pod that mounts the NFS export in its web directory:

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nfs-nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      volumes:
        - name: nfs-nginx
          persistentVolumeClaim:
            claimName: nfs-pvc
      containers:
        - image: nginx
          name: nginx
          volumeMounts:
            - name: nfs-nginx
              mountPath: /usr/share/nginx/html

kubectl apply -f nfs-pvc.yaml
kubectl apply -f deployment.yaml

Apply this file to create an NGINX pod with the NFS volume mounted at /usr/share/nginx/html

Now, let’s enter the pod and create an ‘index.html’ file under ‘/usr/share/nginx/html.’

kubectl get po
kubectl exec -it nfs-nginx-66bcd8b957-7vl2g sh
#now we are into pod
# cd /usr/share/nginx/html
# ls -l
# echo "hello world" >index.html
# ls -l
# exit

cd /data
cd nfs
ls -l
cd default-nfs-pvc-pvc-8a531138-1a09-4e7e-a963-fbec5ecd0a41/

During our testing, we observed that we could access the file (index.html) we created from the ‘/data/nfs’ folder on the server, confirming that the NFS server share is also accessible within the pod.