How to Setup NFS (Network File System) on RHEL/CentOS

How to Setup NFS (Network File System) on RHEL/CentOS

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How to Setup NFS (Network File System) on RHEL/CentOS

NFS (Network File System) is basically developed for sharing of files and folders between Linux/Unix systems by Sun Microsystems in 1980. It allows you to mount your local file systems over a network and remote hosts to interact with them as they are mounted locally on the same system. With the help of NFS, we can set up file sharing between Unix to Linux system and Linux to Unix system.

Benefits of NFS
  1. NFS allows local access to remote files.
  2. It uses standard client/server architecture for file sharing between all unix/Linux based machines.
  3. With NFS it is not necessary that both machines run on the same OS.
  4. With the help of NFS we can configure centralized storage solutions.
  5. Users get their data irrespective of physical location.
  6. No manual refresh needed for new files.
  7. Newer version of NFS also supports acl, pseudo root mounts.
  8. Can be secured with Firewalls and Kerberos.

NFS Services

Its a System V-launched service. The NFS server package includes three facilities, included in the portmap and nfs-utils packages.

  1. portmap : It maps calls made from other machines to the correct RPC service (not required with NFSv4).
  2. nfs: It translates remote file sharing requests into requests on the local file system.
  3. rpc.mountd: This service is responsible for mounting and unmounting of file systems.
Important Files for NFS Configuration
  1. /etc/exports : Its a main configuration file of NFS, all exported files and directories are defined in this file at the NFS Server end.
  2. /etc/fstab : To mount a NFS directory on your system across the reboots, we need to make an entry in /etc/fstab.
  3. /etc/sysconfig/nfs : Configuration file of NFS to control on which port rpc and other services are listening.

Setup and Configure NFS Mounts on Linux Server

To setup NFS mounts, we’ll be needing at least two Linux/Unix machines. Here in this tutorial, I’ll be using two servers.

  1. NFS Server:  IP-192.168.0.175
  2. NFS Client :  IP-192.168.0.176

Installing NFS Server and NFS Client

We need to install NFS packages on our NFS Server as well as on NFS Client machine. We can install it via “yum” (Red Hat Linux) and “apt-get” (Debian and Ubuntu) package installers.

[[email protected] ~]# yum install nfs-utils nfs-utils-lib -y
or
[[email protected] ~]#apt install nfs-utils nfs-utils-lib -y
[[email protected] ~]#yum install portmap (notrequired with NFSv4)
On CentOS 6.x, nfs version 6 is used by default.So,here we don't need to install
portmap package here.

Now start the services on both machines.

[[email protected] ~]# /etc/init.d/nfs start
1nfs
[[email protected] ~]#chkconfig --level 35 nfs on

After installing packages and starting services on both the machines, we need to configure both the machines for file sharing.

Setting Up the NFS Server

First we will be configuring the NFS server.

Configure Export directory

For sharing a directory with NFS, we need to make an entry in “/etc/exports” configuration file. Here I’ll be creating a new directory named “nfsshare” in “/” partition to share with client server, you can also share an already existing directory with NFS.

[[email protected] ~]#mkdir /nfsshare

Now we need to make an entry in “/etc/exports” and restart the services to make our directory shareable in the network.

[[email protected] ~]# vi /etc/exports

/nfsshare      192.168.0.101(rw,sync,no_root_squash)

:wq!

[[email protected] ~]#service nfs restart
Shutting down NFS
daemon:                                  [  OK  ]
Shutting down NFS
mountd:                                  [  OK  ]
Shutting down RPC
idmapd:                                  [  OK  ]
Starting NFS
services:                                [  OK  ]
Starting NFS
mountd:                                  [  OK  ]
Starting NFS
daemon:                                  [  OK  ]
Starting RPC
idmapd:                                  [  OK  ]

In the above example, there is a directory in / partition named “nfsshare” is being shared with client IP “192.168.0.176” with read and write (rw) privilege, you can also use hostname of the client in the place of IP in above example.

NFS Options

NFS Option Which we have used,have a look at all options which we have use while using nfs share.

Some other options we can use in “/etc/exports” file for file sharing is as follows.

  1. ro: With the help of this option we can provide read only access to the shared files i.e client will only be able to read.
  2. rw: This option allows the client server to both read and write access within the shared directory.
  3. sync: Sync confirms requests to the shared directory only once the changes have been committed.
  4. no_subtree_check: This option prevents the subtree checking. When a shared directory is the subdirectory of a larger file system, nfs performs scans of every directory above it, in order to verify its permissions and details. Disabling the subtree check may increase the reliability of NFS, but reduce security.
  5. no_root_squash: This phrase allows root to connect to the designated directory.

For more options with “/etc/exports“, you are recommended to read the man pages for export.

Setting Up the NFS Client

Setting Up the NFS Client

After configuring the NFS server, we need to mount that shared directory or partition in the client server.

Now at the NFS client end, we need to mount that directory in our server to access it locally. To do so, first we need to find out that shares available on the remote server or NFS Server.

[[email protected] ~]# showmount -e 192.168.0.175
Export list for 192.168.0.175:
/nfsshare 192.168.0.176

2nfs

Above command shows that a directory named “nfsshare” is available at “192.168.0.176” to share with your server.

Mount Shared NFS Directory

To mount that shared NFS directory we can use following mount command.

[[email protected] ~]# mount -t nfs 192.168.0.175:/nfsshare /mnt/nfsshare
3nfs

The above command will mount that shared directory in “/mnt/nfsshare” on the client server. You can verify it following command.

[[email protected] ~]# mount | grep nfs
sunrpc on /var/lib/nfs/rpc_pipefs type
rpc_pipefs (rw)
nfsd on /proc/fs/nfsd type nfsd (rw)
192.168.0.175:/nfsshare on /mnt/nfsshare type nfs (rw,vers=4,addr=192.168.0.175,clientaddr=192.168.0.176)

4nfs

 

Test the Working of NFS Setup

You can test this by creating directory or file on one side and check on another side.This will assure your testing
and make you ready to use nfs server.

5nfs

4nfs

The above mount command mounted the nfs shared directory on to nfs client temporarily, to mount an NFS directory permanently on your system across the reboots, we need to make an entry in “/etc/fstab“.

But first umount the mounted directory and check by df -h command.

6nfs

Now mount the directory permanent in fstab file.Please follow the syntax as required for using while mounting nfs share.For more information  regarding this ,please follow on web.

[[email protected]~]# vi /etc/fstab

Add the following new line as shown below.

192.168.0.175:/nfsshare  /mnt/nfsshare  nfs4 rsize=8192,wsize=8192,timeo=14,intr

7nfs

Then save the file and for checking whether entry in fstab file is correct or note.Please put the following command.If there is any error,it will show you all.

[[email protected] ~] mount -a
[[email protected] ~]# df -h
Filesystem         
 Size  Used Avail Use% Mounted on
/dev/sda3   33G  680M   31G   3% 
/tmpfs     499M     0  499M   0% /dev/shm
/dev/sda1   477M   25M  427M   6% /boot
192.168.0.175:/nfsshare  33G  680M   31G   3% /mnt/nfsshare

Test the Working of NFS Setup

We can test our NFS server setup by creating a test file on the server end and check its availability at nfs client side or vice-versa.

Removing the NFS Mount

If you want to unmount that shared directory from your server after you are done with the file sharing, you can simply unmount that particular directory with “umount” command. See this example below.

[[email protected] ~]# umount /mnt/nfsshare

You can see that the mounts were removed by then looking at the file system again.

[[email protected] ~]# df -h

You’ll see that those shared directories are not available any more.

 

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CEO, KV IT-Solutions Pvt. Ltd. | [email protected] | 9810028374|
Linux Professional and an Industrial Trainer | 20 + years Experience in IT Industry

” We are born free, No Gate and Windows can snatch our freedom “

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