Guide to Setting Up NFS Shared File System on CentOS 7 Server

Setting Up NFS Server on CentOS 7

This guide uses CentOS 7. Note: CentOS 6 is end-of-life; using a newer distribution is recommended.

1. Basic Server Security

Before installing services, perform basic security hardening.

1.1 Change SSH Port

Edit the SSH configuration file:

vi /etc/ssh/sshd_config

Find the line #Port 22, uncomment it, and change 22 to another port (e.g., 2222). Save, exit, and restart the SSH service:

systemctl restart sshd

Note: Ensure the firewall allows the new port and reconnect using it to avoid being locked out.

1.2 Create a Regular User

Use a regular user for daily operations:

useradd xiaohost
passwd xiaohost

1.3 Disable Root SSH Login

Edit the SSH configuration file again:

vi /etc/ssh/sshd_config

Find PermitRootLogin and set it to no. Save, exit, and restart SSH:

systemctl restart sshd

2. Update the System

Update package lists before installing software:

yum -y update

Note: yum update updates all packages to the latest versions from repositories, handling dependencies. It differs slightly from yum upgrade, which may remove obsolete dependency packages. Choose based on your needs.

3. Install NFS Service

Install the required NFS server packages:

yum install -y nfs-utils

4. Configure NFS Share

The main NFS configuration file is /etc/exports. Create it if it doesn't exist.

vim /etc/exports

Key Files and Commands:

• Configuration file: /etc/exports – Defines shared directories and client access permissions.
• Server management command: /usr/sbin/exportfs – Manages exported file systems.
• Log files: Located in /var/lib/nfs/. etab records exported directories and detailed permissions; xtab records connected client information.
• Client query command: /usr/sbin/showmount – Used by clients to view shared resources on the NFS server.

A simple configuration example (add to /etc/exports):

/data/share 192.168.1.0/24(rw,sync,no_root_squash)

This shares the /data/share directory to the 192.168.1.0/24 subnet with read-write (rw) permissions, synchronous writes (sync), and allows root users to retain their privileges (no_root_squash). After configuration, start and enable the NFS service:

systemctl start nfs-server
systemctl enable nfs-server

Then use exportfs -arv to re-export the configuration and apply changes immediately.