How to Setup Dynamic NFS Provisioning in Kubernetes Cluster

In this post, we will show you how to setup dynamic nfs provisioning in Kubernetes (k8s) cluster.

Dynamic NFS storage provisioning in Kubernetes allows you to automatically provision and manage NFS (Network File System) volumes for your Kubernetes applications on-demand. It enables the creation of persistent volumes (PVs) and persistent volume claims (PVCs) without requiring manual intervention or pre-provisioned storage.

The NFS provisioner is responsible for dynamically creating PVs and binding them to PVCs. It interacts with the NFS server to create directories or volumes for each PVC.

Prerequisites

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

Without any further delay, let’s deep dive into steps

Step1) Prepare the NFS Server

In my case, I am going to install NFS server on my Kubernetes master node (Ubuntu 22.04). Login to master node and run following commands,

$ sudo apt update
$ sudo apt install nfs-kernel-server -y

Create the following folder and share it using nfs,

$ sudo mkdir /opt/dynamic-storage
$ sudo chown -R nobody:nogroup /opt/dynamic-storage
$ sudo chmod 2770 /opt/dynamic-storage

Add the following entries in /etc/exports file

$ sudo vi /etc/exports
/opt/dynamic-storage 192.168.1.0/24(rw,sync,no_subtree_check)

Save and close the file.

Note: Don’t forget to change network in exports file that suits to your deployment.

To make above changes into the effect, run

$ sudo exportfs -a
$ sudo systemctl restart nfs-kernel-server
$ sudo systemctl status nfs-kernel-server

On the worker nodes, install nfs-common package using following apt command.

$ sudo apt install nfs-common -y

Step 2) Install and Configure NFS Client Provisioner

NFS subdir external provisioner deploy the NFS client provisioner in your Kubernetes cluster. The provisioner is responsible for dynamically creating and managing Persistent Volumes (PVs) and Persistent Volume Claims (PVCs) backed by NFS storage.

So, to install NFS subdir external provisioner, first install helm using following set of commands,

$ curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3
$ chmod 700 get_helm.sh
$ ./get_helm.sh

Enable the helm repo by running following beneath command,

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

Deploy provisioner using following helm command

$ helm install -n nfs-provisioning --create-namespace nfs-subdir-external-provisioner nfs-subdir-external-provisioner/nfs-subdir-external-provisioner --set nfs.server=192.168.1.139 --set nfs.path=/opt/dynamic-storage

Above helm command will automatically create nfs-provisioning namespace and will install nfs provisioner pod/deployment, storage class with name (nfs-client) and will created the required rbac.

$ kubectl get all -n nfs-provisioning
$ kubectl get sc -n nfs-provisioning

Perfect, output above confirms that provisioner pod and storage class is created successfully.

Step 3) Create Persistent Volume Claims (PVCs)

Let’s a create PVC to request storage for your pod or deployment. PVC will request for a specific amount of storage from a StorageClass (nfs-client).

$ vi demo-pvc.yml
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: demo-claim
  namespace: nfs-provisioning
spec:
  storageClassName: nfs-client
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 10Mi

save & close the file.

Run following kubectl command to create pvc using above created yml file,

$ kubectl create -f demo-pvc.yml

Verify whether PVC and PV are created or not,

$ kubectl get pv,pvc -n nfs-provisioning

Great, above output shows that pv and pvc are created successfully.

Step 4) Test and Verify Dynamic NFS Provisioning

In order to test and verify dynamic nfs provisioning, spin up a test pod using following yml file,

$ vi test-pod.yml
kind: Pod
apiVersion: v1
metadata:
  name: test-pod
  namespace: nfs-provisioning
spec:
  containers:
  - name: test-pod
    image: busybox:latest
    command:
      - "/bin/sh"
    args:
      - "-c"
      - "touch /mnt/SUCCESS && sleep 600"
    volumeMounts:
      - name: nfs-pvc
        mountPath: "/mnt"
  restartPolicy: "Never"
  volumes:
    - name: nfs-pvc
      persistentVolumeClaim:
        claimName: demo-claim

Deploy the pod using following kubectl command,

$ kubectl create -f test-pod.yml

Verify the status of test-pod,

$ kubectl get pods -n nfs-provisioning

Login to the pod and verify that nfs volume is mounted or not.

$ kubectl exec -it test-pod -n nfs-provisioning /bin/sh

Great, above output from the pod confirms that dynamic NFS volume is mounted and accessible.

In the last, delete the pod and PVC and check whether pv is deleted automatically or not.

$ kubectl delete -f test-pod.yml
$ kubectl delete -f demo-pvc.yml
$ kubectl get pv,pvc -n  nfs-provisioning

That’s all from this post, I hope you have found it informative. Feel free to post your queries and feedback in below comments section.

Also Read: How to Install Ansible AWX on Kubernetes Cluster