Title: Kubernetes Cluster Installation with NFS - Step-by-Step Guide

Introduction:
In this article, I will guide you through the process of setting up NFS (Network File System) in a Kubernetes cluster. NFS provides a simple and reliable way to share files across a network. We will go through each step required for the installation and configuration of NFS in a Kubernetes cluster.

Table of Contents:
1. Prerequisites
2. Install and Configure NFS Server
3. Create Persistent Volumes
4. Deploy NFS Client Provisioner
5. Verification and Testing

Step 1: Prerequisites
Before we begin, make sure you have the following prerequisites in place:
- A working Kubernetes cluster
- Root access to all cluster nodes
- Knowledge of basic Kubernetes concepts

Step 2: Install and Configure NFS Server
To install and configure the NFS server, follow these steps:

1. SSH into the node that will act as the NFS server.
2. Install the NFS server package using the following command:
```
sudo apt-get install nfs-kernel-server
```

3. Configure the NFS exports file to specify the directory you want to share. Open the exports file using a text editor:
```
sudo nano /etc/exports
```

4. Add the following line to the exports file, replacing `/path/to/share` with the actual directory you want to share:
```
/path/to/share *(rw,sync,no_subtree_check)
```

5. Save the file and exit the text editor.

6. Restart the NFS server for the changes to take effect:
```
sudo systemctl restart nfs-kernel-server
```

Step 3: Create Persistent Volumes
Persistent volumes (PVs) are used to define storage resources in a Kubernetes cluster. To create PVs backed by NFS, follow these steps:

1. Create a YAML file named `nfs-pv.yaml` and add the following content:
```
apiVersion: v1
kind: PersistentVolume
metadata:
name: my-pv
spec:
capacity:
storage: 1Gi
accessModes:
- ReadWriteMany
nfs:
server:
path: /path/to/share
```

2. Replace `` with the IP address of your NFS server.

3. Apply the PV definition to your cluster using the following command:
```
kubectl apply -f nfs-pv.yaml
```

Step 4: Deploy NFS Client Provisioner
The NFS client provisioner is a dynamic provisioner that creates PVs automatically whenever a PVC (PersistentVolumeClaim) is created. To deploy the NFS client provisioner, follow these steps:

1. Clone the NFS client provisioner repository using the following command:
```
git clone https://github.com/kubernetes-incubator/external-storage.git
```

2. Change into the `external-storage/nfs-client` directory:
```
cd external-storage/nfs-client
```

3. Edit the `deploy/deployment.yaml` file and replace the `` and `` placeholders with the IP address of your NFS server and the shared directory path respectively.

4. Deploy the NFS client provisioner using the following command:
```
kubectl create -f deploy/deployment.yaml
```

Step 5: Verification and Testing
To verify the installation and test the NFS mount, follow these steps:

1. Create a YAML file named `nfs-pvc.yaml` and add the following content:
```
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: my-pvc
spec:
accessModes:
- ReadWriteMany
resources:
requests:
storage: 1Gi
```

2. Apply the PVC definition to your cluster using the following command:
```
kubectl apply -f nfs-pvc.yaml
```

3. Create a pod that uses the NFS volume by applying the following YAML file:
```
apiVersion: v1
kind: Pod
metadata:
name: my-pod
spec:
containers:
- name: my-container
image: ubuntu
volumeMounts:
- name: nfs-volume
mountPath: /mnt/nfs
volumes:
- name: nfs-volume
persistentVolumeClaim:
claimName: my-pvc
```

4. Use the following command to check if the pod is running:
```
kubectl get pods
```

5. Exec into the pod to verify the NFS mount:
```
kubectl exec -it my-pod -- /bin/bash
```

6. Once inside the pod, navigate to the mount path `/mnt/nfs` and create a file to ensure read and write operations are successful.

Conclusion:
In this article, we have learned how to install and configure NFS in a Kubernetes cluster. By following the step-by-step guide, you should now have a functioning NFS server and client provisioner. You can use PVs and PVCs to dynamically allocate storage backed by NFS. This setup allows for shared file storage within your Kubernetes cluster.