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    Configuring an NFS server and NFS client in CentOS / RHEL 7

    Configuring an NFS server and NFS client in CentOS / RHEL 7


    NFS allows a linux server to share directories with other UNIX clients over network. NFS server exports a directory and NFS client mounts this directory.

    Configuring NFS server

    1. Install the required nfs packages  :

    [root@kubemaster ~]# rpm -qa | grep nfs-utils
    [root@kubemaster ~]# yum install nfs-utils rpcbind -y Loaded plugins: fastestmirror
    base                                                                                                     | 3.6 kB  00:00:00

    2. Enable the services at boot time:

    [root@kubemaster ~]# systemctl enable nfs-server
    Created symlink from /etc/systemd/system/multi-user.target.wants/nfs-server.service to /usr/lib/systemd/system/nfs-server.service.
    [root@kubemaster ~]# systemctl enable rpcbind
    [root@kubemaster ~]# systemctl start rpcbind
    [root@kubemaster ~]# systemctl start nfs-server

    3. Start the NFS services:

    [root@kubemaster ~]# systemctl start nfs-server
    [root@kubemaster ~]#
    4. Check the status of NFS service:

    [root@kubemaster ~]# systemctl status nfs
    ● nfs-server.service - NFS server and services
       Loaded: loaded (/usr/lib/systemd/system/nfs-server.service; enabled; vendor preset: disabled)
       Active: active (exited) since Wed 2019-11-20 21:39:11 IST; 21s ago
      Process: 1925 ExecStartPost=/bin/sh -c if systemctl -q is-active gssproxy; then systemctl reload gssproxy ; fi (code=exited, status=0/SUCCESS)
      Process: 1908 ExecStart=/usr/sbin/rpc.nfsd $RPCNFSDARGS (code=exited, status=0/SUCCESS)
      Process: 1906 ExecStartPre=/usr/sbin/exportfs -r (code=exited, status=0/SUCCESS)
     Main PID: 1908 (code=exited, status=0/SUCCESS)
       CGroup: /system.slice/nfs-server.service

    Nov 20 21:39:11 kubemaster systemd[1]: Starting NFS server and services...
    Nov 20 21:39:11 kubemaster systemd[1]: Started NFS server and services.

    5. Create a shared directory:

    [root@kubemaster ~]# mkdir /nfstest

    6. Export the directory. The format of the /etc/exports file is :

    dir client1 (options) [client2(options)...]
    Client options include (defaults are listed first) :
    ro / rw :
    a) ro : allow clients read only access to the share.
    b) rw : allow clients read write access to the share.
    sync / async :
    a) sync : NFS server replies to request only after changes made by previous request are written to disk.
    b) async : specifies that the server does not have to wait.
    wdelay / no_wdelay
    a) wdelay : NFS server delays committing write requests when it suspects another write request is imminent.
    b) no_wdelay : use this option to disable to the delay. no_wdelay option can only be enabled if default sync option is enabled.
    no_all_squash / all_squash :
    a) no_all_squash : does not change the mapping of remote users.
    b) all_squash : to squash all remote users including root.
    root_squash / no_root_squash :
    a) root_squash : prevent root users connected remotely from having root access. Effectively squashing remote root privileges.
    b) no_root_squash : disable root squashing.

    Example :

    [root@kubemaster ~]# vi /etc/exports
    [root@kubemaster ~]# cat /etc/exports
    /nfstest *(rw)
    [root@kubemaster ~]#

    7. Exporting the share :

    [root@kubemaster ~]# exportfs -r
    [root@kubemaster ~]# exportfs -a

    8. Restart the NFS service:

    # systemctl restart nfs-server

    Configuring NFS client

    1. Install the required nfs packages if not already installed on the server :

    [root@kubenode1 ~]# rpm -qa | grep nfs-utils
    [root@kubenode1 ~]# yum install nfs-utils -y
    Loaded plugins: fastestmirror
    Determining fastest mirrors
     * base: mirrors.praction.in
     * extras: mirrors.praction.in
     * updates: mirrors.praction.in

    2. Use the mount command to mount exported file systems. Syntax for the command:

     mount -t nfs -o options host:/remote/export /local/directory

    [root@kubenode1 ~]# mount -t nfs -o ro,nosuid /nfstestclient

    for Read write mount:
    [root@kubenode1 ~]# mount -t nfs -o rw /nfstestclient
    [root@kubenode1 ~]# df -h /nfstestclient
    Filesystem              Size  Used Avail Use% Mounted on  6.2G  3.8G  2.5G  61% /nfstestclient


    On server Create files inside the share :

    [root@kubemaster ~]# touch a b c d
    [root@kubemaster ~]# mv a b c d /nfstest/

    On Client Check:

    [root@kubenode1 ~]# ls -latr /nfstestclient
    total 0
    dr-xr-xr-x. 18 root root 265 Nov 20 21:41 ..
    -rw-r--r--   1 root root   0 Nov 20 21:43 b
    -rw-r--r--   1 root root   0 Nov 20 21:43 a
    -rw-r--r--   1 root root   0 Nov 20 21:43 d
    -rw-r--r--   1 root root   0 Nov 20 21:43 c
    drwxr-xr-x   2 root root  42 Nov 20 21:44 .
    [root@kubenode1 ~]#

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