Change hostname in Centos 7

On a CentOS Linux 7 server you can use any one of the following tool to manage hostnames:

1. hostnamectl command : Control the system hostname. This is recommended method.
2. nmtui command : Control the system hostname using text user interface (TUI).
3. nmcli command : Control the system hostname using CLI part of NetworkManager.

Types of hostnames

The hostname can be configured as follows

1. Static host name assigned by sysadmin. For example, “server1”, “wwwbox2”, or “centos7.winnix.local”.
2. Transient/dynamic host name assigned by DHCP or mDNS server at run time.
3. Pretty host name assigned by sysadmin/end-users and it is a free-form UTF8 host name for presentation to the user. For example, “Vivek’s netbook”.
   

   Method #1: hostnamectl command

   Let us see how to use the hostnamectl command.

   How do I see the host names?

   $ hostnamectl
## OR ##
$ hostnamectl status
   Sample outputs:

      Static hostname: localhost.localdomain
            Icon name: computer-vm
              Chassis: vm
           Machine ID: 0f5af28b7bae42dcbcf0de85ae9be652
              Boot ID: 054432a36e244bd78114c19a0f89edc6
       Virtualization: vmware
     Operating System: CentOS Linux 8 (Core)
          CPE OS Name: cpe:/o:centos:centos:8
               Kernel: Linux 4.18.0-147.8.1.el8_1.x86_64
         Architecture: x86-64
   

   How do I set the host name?

   The syntax is:
   # hostnamectl set-hostname Your-New-Host-Name-Here
# hostnamectl set-hostname "Your New Host Name Here" --pretty
# hostnamectl set-hostname Your-New-Host-Name-Here --static
# hostnamectl set-hostname Your-New-Host-Name-Here --transient
   To set host name to “Centos7Serv”, enter:
   # hostnamectl set-hostname Centos7Serv
   To set static host name to “centos7.winnix.local”, enter:
   # hostnamectl set-hostname centos7.winnix.local --static
   To set pretty host name to “Centos7 Winnix Tech”, enter:
   # hostnamectl set-hostname "Centos7 Winnix Tech" --pretty
   To verify new settings, enter:
   # hostnamectl status
   Sample outputs:

     Static hostname: centos7.winnix.local
      Pretty hostname: Centos7 Winnix Tech
            Icon name: computer-vm
              Chassis: vm
           Machine ID: 0f5af28b7bae42dcbcf0de85ae9be652
              Boot ID: 054432a36e244bd78114c19a0f89edc6
       Virtualization: vmware
     Operating System: CentOS Linux 7 (Core)
          CPE OS Name: cpe:/o:centos:centos:7
               Kernel: Linux 4.18.0-147.8.1.el8_1.x86_64
         Architecture: x86-64

   How do I delete a particular host name?

   The syntax is:
   # hostnamectl set-hostname ""
# hostnamectl set-hostname "" --static
# hostnamectl set-hostname "" --pretty

   How do I change host name remotely?

   Use any one of the following syntax:
   # ssh root@server-ip-here hostnamectl set-hostname server1
   OR set server1 as host name on a remote server called 192.168.1.42 using ssh:
   # hostnamectl set-hostname server1 -H root@192.168.1.42

   Method #2: nmtui command

   You can set host name using nmtui command which has text user interface for new users:
   # nmtui
   Sample outputs:

   

   Fig.01: Use nmtui to set hostname on a CentOS 7

   Use the Down arrow key > select the “Set system hostname” menu option > Press the “Ok” button:

   

   Fig.02: Set hostname

   You will see the confirmation box as follows:

   

   Fig.03: New hostname confirmed

   Finally, restart hostnamed service by typing the following command
   # systemctl restart systemd-hostnamed
   To verify changes, enter:
   # hostnamectl status
   Sample outputs:

   [root@winnix ~]# hostnamectl status

    Static hostname: centos-7-rc
            Icon name: computer
              Chassis: n/a
           Machine ID: b5470b10ccfd49ed8e4a3b0e953a53c3
              Boot ID: f79de79e2dac4670bddfe528e826b61f
       Virtualization: oracle
     Operating System: CentOS Linux 7 (Core)
          CPE OS Name: cpe:/o:centos:centos:7
               Kernel: Linux 3.10.0-229.1.2.el7.x86_64
         Architecture: x86_64

   Fig.04: CentOS 7 / RHEL View Host Name Details Using hostnamectl Command

   Method #3: nmcli command

   The nmcli is a command line tool for controlling NetworkManager and reporting network status.

   To view the host name using nmcli command:

   The syntax is:
   # nmcli general hostname

   To set the host name using nmcli command:

   The syntax is:
   # nmcli general hostname R2-D2
# nmcli general hostname server42.cyberciti.biz
   Finally, restart the systemd-hostnamed service:
   # systemctl restart systemd-hostnamed

Change hostname in Centos 6

1. Using a text editor, open the server’s /etc/sysconfig/network file.

    # sudo nano /etc/sysconfig/network
   

2. Modify the HOSTNAME= value to match your FQDN hostname.

    HOSTNAME=myserver.domain.com
   

3. For internal networking, change the host that is associated with the main IP address for your server (found at /etc/hosts).

    127.0.0.1      localhost localhost.localdomain
   
    123.45.67.89   hostname.domain.com   hostname
   
   
    -- INSERT --                         2,43-57    ALL
   

4. Run the hostname command. This command lets you change the hostname on the server that the command line remembers, but it does not actively update all programs that are running under the old hostname.

    [root@defiant ~]# hostname hostname.domain.com
   
    [root@defiant ~]# hostname
   
    hostname.domain.com
   
    [root@defiant ~]#
   

5. Restart networking on your server to ensure that changes will persist on restart.

    # /etc/init.d/network restart