Change hostname on CentOS 7

After installing the CentOS 7 on my server, i tried to change host name by modifying the /etc/sysconfig/network; it did not take an effect of the modification. Even after multiple reboot of server, the host name remains localhost.localdomain. The procedure to change the host name in CentOS 7 is now totally different from the previous version, this guide will help you to setup the host name on CentOS 7 / RHEL 7.

CentOS 7 supports three class of Host Names:

Static – The static host name is traditional host which can be chosen by the user and is stored in /etc/hostname file.

Transient – The transient host name is maintained by kernel and can be changed by DHCP and mDNS.

Pretty – It is a free form UTF -8 host name for the presentation to the user.

HostName can be,

• 64 character in a length
• Recommend to have FQDN
• Consists of a-z,A-Z, 0-9, “-”, “_” and “.” only

How to Change:

Before changing the host name, lets check the current host name.

[root@localhost ~]# hostname localhost.localdomain

1. nmtui tool: you using command nmtui

NetworkManaget tool is used to set the static host name in /etc/hostname file.

Set the host name.

restart the hostnamed to force the hostnamectl to notice the change in static host name.

[root@localhost ~]# systemctl restart systemd-hostnamed

You can verify the change in host name.

[root@localhost ~]# hostname web.sysadmin.com.vn [root@localhost ~]# cat /etc/hostname web.sysadmin.com.vn [root@localhost ~]# cat /etc/sysconfig/network # Created by anaconda sysadmin [root@localhost ~]#

2. hostnamectl:

hostnamectl is used to change the host name, with this tool we can change all the three class of host name; here we look only static host name.

Check the current host name.

[root@server ~]# hostnamectl status

[root@localhost ~]# hostnamectl status Static hostname: web.sysadmin.com.vn Icon name: computer Chassis: n/a Machine ID: 3132ab42b3b7405bbdc647ce36ca659f Boot ID: 0938b49f7e4045b899a110ccf17b54a7 Virtualization: vmware Operating System: CentOS Linux 7 (Core) CPE OS Name: cpe:/o:centos:centos:7 Kernel: Linux 3.10.0-123.6.3.el7.x86_64 Architecture: x86_64

Set the hostname.

[root@server ~]# hostnamectl set-hostname web.sysadmin.com.vn

Check the host name again (Close the session and open new session using putty or console)

[root@client ~]# hostnamectl status

[root@localhost ~]# hostnamectl status Static hostname: web.sysadmin.com.vn Icon name: computer Chassis: n/a Machine ID: 3132ab42b3b7405bbdc647ce36ca659f Boot ID: 0938b49f7e4045b899a110ccf17b54a7 Virtualization: vmware Operating System: CentOS Linux 7 (Core) CPE OS Name: cpe:/o:centos:centos:7 Kernel: Linux 3.10.0-123.6.3.el7.x86_64 Architecture: x86_64

If you use this command, you do not require to notify the change in host name. Close the current session and re launch the terminal.

3. nmcli tool:

It can be used to query and setup the static host name in /etc/hostname file.

Check the hostname.

[root@localhost ~]# nmcli general hostname web.sysadmin.com.vn

Change the host name.

[root@localhost ~]# nmcli general hostname web.sysadmin.com.vn

restart the hostnamed to force the hostnamectl to notice the change in static host name.

[root@localhost ~]# systemctl restart systemd-hostnamed

4. Edit /etc/hostname

This is the simple, but requires a reboot of server to take an effect.

Note: Use the hostnamectl to change the host name, which fair better than other commands and does not require to update the kernel about the change in host name.