Steps to Build an NFS Server

1. Install NFS Server on Linux (VM or Kubernetes Node)

If you're using a VM or any Linux-based system as the NFS server, you first need to install the NFS server package.

For Ubuntu/Debian:

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

Create a directory that will be shared over NFS. For example:

sudo mkdir -p /mnt/data
sudo chmod 777 /mnt/data
sudo chown nobody:nogroup /mnt/data

You'll need to configure the NFS exports to specify which directories you want to share and with which permissions.

Edit the NFS exports file:

sudo nano /etc/exports

Add the following line to the file, allowing any IP to access the directory (replace * with specific IP ranges for security):

/mnt/data *(rw,sync,no_subtree_check)

rw: Allows read-write access.
sync: Ensures data is written to disk before returning a response.
no_subtree_check: Prevents checking the file system for each request (to improve performance).

After editing the /etc/exports file, export the shared directories with the following command:

sudo exportfs -a

To confirm that the export was successful, run:

sudo exportfs -v

Start and enable the NFS server to run on boot:

For Ubuntu/Debian:

sudo systemctl enable nfs-kernel-server
sudo systemctl start nfs-kernel-server

For most systems:

sudo systemctl status nfs-server

Ensure that the required NFS ports are open on the NFS server and accessible from the client.

Check the NFS Ports:

sudo rpcinfo -p

Look for services like nfs, mountd, and portmapper in the output.

Example:

   program vers proto   port  service
    100000    4   tcp    111  portmapper
    100005    1   udp  20048  mountd
    100003    3   tcp   2049  nfs

If you're using a firewall, open the necessary ports to allow NFS traffic. The typical ports used for NFS are 2049 (NFS) and 111 (RPC).

For UFW (Ubuntu firewall):

sudo ufw allow from any to any port nfs

From another machine (which will act as the client), test the NFS share.

Mount the NFS share to a local directory (replace nfs-server-ip with the IP of the NFS server):

sudo mount -t nfs nfs-server-ip:/mnt/data /mnt

You should now be able to read and write files to the /mnt/data directory over NFS.