NFS-server-for-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

1. Pre-installed Kubernetes Cluster
2. Root access to all nodes(servers)

Step 1: Installing the NFS Server(NFS-Server)

Do this in a seperate VM and dedicate that VM to storage purpose of NFS only

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

Step 2: Create a directory to export(NFS-Server)

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

Step 3: Export directory and restart NFS service(NFS-Server)

sudo nana /etc/exports
# add this line 
/nfs/kubedata   *(rw,sync,no_subtree_check,no_root_squash,no_all_squash,insecure)
# save this and close the file

sudo exportfs -av

sudo systemctl restart nfs-server

sudo systemctl status nfs-server

Step 4: Install NFS client packages on Kubernetes Nodes(Msster and Worker both)

sudo apt update
sudo apt install nfs-common -y

Step 5: Install and Configure NFS Client Provisioner(Master Node)

#install helm if not present in the kubernetes cluster
wget https://get.helm.sh/helm-v3.7.1-linux-amd64.tar.gz || curl -LO https://get.helm.sh/helm-v3.7.1-linux-amd64.tar.gz
tar -zxvf helm-v3.7.1-linux-amd64.tar.gz
sudo mv linux-amd64/helm /usr/local/bin/helm
helm version

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

kubectl create namespace nfs-server

helm install nfs-subdir-external-provisioner \
nfs-subdir-external-provisioner/nfs-subdir-external-provisioner -n nfs-server\
--set nfs.server=<IP address of the NFS-Server> \
--set nfs.path=/data/nfs \
--set storageClass.onDelete=true

# Check pods and storage classes:
kubectl get pod -n nfs-server
kubectl get sc

Step 6: Verify the nfs working with kubernetes(Master Node)

Instead of manually creating PVs, you only need to create PVCs. The provisioner will handle the rest, including creating the PVs on the NFS server and binding them to the PVCs.

vi nfs-deploy.yml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs-test-deployment
spec:
  replicas: 1
  selector:
	matchLabels:
	  app: nfs-test
  template:
	metadata:
	  labels:
		app: nfs-test
	spec:
	  containers:
	  - name: nginx
		image: nginx
		volumeMounts:
		- name: nfs-pv
		  mountPath: /usr/share/nginx/html
	  volumes:
	  - name: nfs-pv
		persistentVolumeClaim:
		  claimName: nfs-pvc
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-pvc
spec:
  accessModes:
	- ReadWriteMany
  storageClassName: nfs-default-storage-class
  resources:
	requests:
	  storage: 1Gi

Execute this command

kubectl apply -f nfs-deploy.yml

Then ssh to the nginx pod and verify the nfs

kubectl exec -it nfs-test-deployment-77f6d8dbd6-7j56q -- /bin/bash

df -kh

You will that all of the disk usage here and whatever change are done in the pods shared directory will be reflected in the nfs-server