Install and Configure NFS Server on RHEL/CentOS

In this tutorial, we will learn how to install and configure NFS Server on RHEL/CentOS. Network File system (NFS) is a commonly used file-based storage system that allows remote systems to access files over a computer network and interact with them as if they were locally mounted. This enables system administrators to group resources onto centralized servers on a network for easy sharing.

Installing NFS Server on RHEL/CentOS

Simple Setup Architecture

To configure NFS server, we will be using two CentOS 8 and Rocky Linux servers acting as the NFS Server while the other acting as the NFS Client respectively.

Install NFS Packages on RHEL/CentOS

To install NFS packages on both the Server and the Client, execute the command below;

yum install nfs-utils -y

Configure NFS Server on RHEL/CentOS

Define ID Mapping Domain

ID mapping is the process of mapping user and group IDs between different systems to ensure that file access permissions are correctly applied.

Thus, once the packages are installed, edit the /etc/idmapd.conf file as follows on NFS server;

vim /etc/idmapd.conf

Uncomment the line below by removing #;

#Domain = local.domain.edu

Then replace the domain with your appropriate NFS server domain name.

Domain = kifarunix-demo.com

The domain usually defaults to the host’s DNS domain name.

Save and exit the file;

Restart the rpcidmapd service to apply the changes:

systemctl restart rpcbind

Create NFS Share Directory

Create a directory that you want to share over the network via NFS server. For example, create a directory named “Shared” in the “/home” directory.

mkdir /home/share

Configure NFS exports

An export is a directory or file system that is made available to remote clients for sharing. When you set up an NFS server, you can specify which directories or file systems on the server should be available for clients to access. This is done by configuring NFS exports. Once an export is configured, clients can access it by mounting it as a local file system.

Thus, edit the file /etc/exports;

vim /etc/exports

Add file system or directory to be exported to client and specify the options to apply as in the screenshot below:

Each entry for an exported file system has the following structure:

export host(options)

where:

• export is the file system or directory to be mounted on remote host
• host is the remote host (Network, host, or every system,*,)
• options are comma separated list of options

For our case:

/home/share 192.168.56.0/24(rw,sync,no_root_squash)

Options used as in the above are:

• rw allows the client server both read and write access within the shared directory.
• sync ensures that changes made are synchronized immediately.
• no_root_squash allows root user to write files to the NFS share.

Save and exit the file.

For more options, check nfs man pages.

Start and Enable NFS server

Start the NFS server and enable it to start at boot time using the following commands:

systemctl enable --now nfs-server

Open Firewall ports for NFS

There are several ports that need to be open in the firewall on both the server and client machines. Here are the ports that should be open:

1. Port 111: This is the portmapper daemon, which maps RPC services to port numbers. Both TCP and UDP need to be open.
2. Port 2049: This is the NFS daemon, which handles all NFS requests. Both TCP and UDP need to be open.
3. Port 20048: This is the NFSv4 protocol. Both TCP and UDP need to be open.
4. Port 875: This is the mountd daemon, which handles mount requests. Both TCP and UDP need to be open.
5. Port 892: This is the rpcbind daemon, which is used to manage RPC services. Both TCP and UDP need to be open.

Allow these ports using the commands below;

sudo firewall-cmd --permanent --add-service=nfs
sudo firewall-cmd --permanent --add-service=rpc-bind
sudo firewall-cmd --permanent --add-service=mountd
sudo firewall-cmd --reload

Configure NFS Client on RHEL/CentOS

After configuring the NFS server, the shared directory or file system has to be mounted on the client so it can be accessed.

Define ID Mapping Domain

Just like it was done on the NFS server, edit the /etc/idmap.conf file and add a domain name like before.

vim /etc/idmap.conf

[General]
...
Domain = kifarunix-demo.com

Save and exit the file.

Enable and start rpcbind service

systemctl restart rpcbind

Mount the NFS share on the client

Mount the shared directory on NFS client using the mount command.

Before mounting, you need to discover (finds and accesses NFS exports on an NFS server) NFS exports, that is, the shares available on the NFS server as shown below.

There are two ways to discover which file systems an NFS server exports;

• Using showmount

showmount -e NFS-Server-Address

e.g;

showmount -e fileserver

Sample output;

Export list for fileserver:
/home/share 192.168.56.0/24

• Using mount command

mount NFS-Server:/ /mnt/

e.g;

mount -t nfs fileserver:/ /mnt

Confirm that the shared directory is mounted by using df -hT. See the last line in the screenshot below.

df -hT

...
fileserver:/           nfs4      7.8G  1.2G  6.6G  15% /mnt
fileserver:/home       nfs4      7.8G  1.2G  6.6G  15% /mnt/home
fileserver:/home/share nfs4      7.8G  1.2G  6.6G  15% /mnt/home/share

Configuring NFS Share Automounting on System Boot

• Automount using FSTAB
• Automount using AutoFS

Automount using FSTAB

Edit the /etc/fstab file and add an entry for the NFS share. The entry should include the IP address of the NFS server, the path to the NFS share, the mount point directory, and the mount options. For example:

vim /etc/fstab

fileserver.kifarunix-demo.com:/home/ /mnt               nfs     defaults        0 0

Save the /etc/fstab file and exit the editor.

You can test the mount by running the following command:

sudo mount -a

yum -y install autofs

vim /etc/auto.master

/- /etc/auto.mount

mount-point options location

vim /etc/auto.mount

/mnt -fstype=nfs,rw fileserver.kifarunix-demo.com:/home

systemctl enable --now autofs

df -hT -P /mnt