Mount and unmount network file systems using NFS

6. Create and Configure File Systems

📘Red Hat Certified System Administrator (RHCSA – EX200)

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What is NFS?

• NFS (Network File System) is a protocol that allows a computer (client) to access files over a network as if they were on its local hard drive.
• Example: A developer on one server can read/write files that are physically stored on a different server, without copying them.
• NFS is mostly used in Linux and Unix environments.

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Why NFS is Important in IT

• Shared storage for multiple servers (e.g., web servers accessing the same configuration files).
• Centralized data management (all backups happen from one location).
• Easy collaboration between systems in a network.

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How NFS Works

1. Server: The machine that shares directories.
2. Client: The machine that mounts and uses the shared directories.
3. Exports: The directories on the server that are available to clients.
4. Mounting: Connecting the client to the NFS server to use the shared folder.

Think of mounting like “connecting to a shared drive” on another server.

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Step 1: Install NFS Tools

• On Linux, you need NFS packages installed:

# On the server (Red Hat/CentOS/Fedora)
sudo yum install nfs-utils -y# On the client
sudo yum install nfs-utils -y

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Step 2: Configure the NFS Server

1. Create a directory to share:

sudo mkdir -p /srv/nfs/shared

2. Give proper permissions:

sudo chown nobody:nogroup /srv/nfs/shared
sudo chmod 777 /srv/nfs/shared

3. Edit /etc/exports file to define which clients can access the directory:

/srv/nfs/shared 192.168.1.10(rw,sync,no_root_squash)

• 192.168.1.10 → IP of the client allowed to connect.
• rw → read and write permission.
• sync → changes are written immediately.
• no_root_squash → allows root on client to have root permissions on the shared folder.

4. Start and enable NFS server services:

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

5. Export the directories:

sudo exportfs -a

6. Check shared directories:

sudo exportfs -v

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Step 3: Mount NFS on the Client

1. Create a mount point:

sudo mkdir -p /mnt/nfs/shared

2. Mount the NFS share:

sudo mount 192.168.1.20:/srv/nfs/shared /mnt/nfs/shared

• 192.168.1.20 → NFS server IP.
• /mnt/nfs/shared → local mount point on the client.

3. Verify mount:

mount | grep nfs

or

df -h

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Step 4: Make NFS Mount Persistent (Optional but Exam-Relevant)

• Edit /etc/fstab to mount NFS automatically at boot:

192.168.1.20:/srv/nfs/shared /mnt/nfs/shared nfs defaults 0 0

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Step 5: Unmount NFS

• To safely unmount:

sudo umount /mnt/nfs/shared

• Always unmount before shutting down or disconnecting the network share to avoid data corruption.

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Step 6: Common NFS Commands

Command	Purpose
showmount -e <server>	Show exported directories from server
mount -t nfs <server>:/path /mountpoint	Mount NFS manually
umount /mountpoint	Unmount NFS
exportfs -v	List exported directories on server

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Key Points for Exam

1. Server vs Client roles: Know which commands go where.
2. NFS Permissions: rw, ro, sync, no_root_squash are important.
3. Mounting/unmounting: You must know mount, umount, and /etc/fstab.
4. Network accessibility: NFS requires network connectivity; the client must reach the server.
5. Verification: Always check mount, df -h, or showmount -e.

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Real-Life IT Examples

• Multiple Linux web servers reading from the same content directory on a central server.
• Backup servers accessing critical data directories over the network.
• A development team accessing a shared code repository folder hosted on another server.

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✅ Summary

• NFS allows network-wide file sharing.
• Configure server exports, mount client directories, and unmount safely.
• /etc/exports and /etc/fstab are key files to remember.
• Use NFS commands to verify and troubleshoot.