Saturday, July 9, 2016

Commands to Configure hostname on CentOS 7 and RHEL 7

Hostname is defined as label or name of a computer and network device. In this article we will discuss how to set and modify hostname on CentOS 7 & RHEL 7. There are three different commands through which we can query, set and modify hostname.
  • hostnamectl
  • nmtui
  • nmcli
Types of Hostname that we can set on CentOS 7 and RHEL 7 server.
  • Static Hostname — It is conventional hostname that we set on the servers and as the name suggest hostname will be static and persistent accross the reboot.Static hostname is stored in the file /etc/hostname.
  •  Transient Hostname — It is the hostname which is obtained from DHCP and mDNS. Transient hostname might be temporary because it is only temporarily written to kernel hostname.
  •  Pretty Hostname — It is a hostname that can include all kind of special characters. Pretty hostname is stored in the file /etc/machine-info .
Commands to check the hostname :
[root@localhost ~]# hostname
[root@localhost ~]# hostnamectl status
[root@localhost ~]# hostnamectl

hostnamectl command :

hostnamectl command is used to configure,modify and query hostname. Basic syntax is listed below :
# hostnamectl
Let’s set the static hostname ‘
[root@localhost ~]# hostnamectl set-hostname ""
[root@localhost ~]#
Verify the new hostname using hostnamectl and hostname command :
Remove or clear the hostname (
[root@cloud ~]# hostnamectl set-hostname ""
[root@cloud ~]# 
[root@cloud ~]# hostname
[root@cloud ~]# hostnamectl 
 Static hostname: n/a
Transient hostname: localhost
 Icon name: computer
 Chassis: n/a
 Machine ID: a5c10f2a26324894a3b0b83d504c1ff2
 Boot ID: c3ff9d084b364b56bb0d588b64ff6f1a
 Virtualization: oracle
 Operating System: CentOS Linux 7 (Core)
 CPE OS Name: cpe:/o:centos:centos:7
 Kernel: Linux 3.10.0-123.el7.x86_64
 Architecture: x86_64
[root@cloud ~]#
Set Pretty Hostname :
[root@cloud ~]# hostnamectl set-hostname "Pradeep Antil's CentOS-7 Laptop" --pretty
[root@cloud ~]#
Remove Pretty hostname :
[root@cloud ~]# hostnamectl set-hostname "" --pretty
Set Hostname on the Remote Server from your local machine.
Syntax :
# hostnamectl set-hostname -H @
Above command will use ssh for connecting and authentication for remote server.
root@linuxworld:~# hostnamectl set-hostname -H
root@'s password:

nmtui command :

nmtui stands for ‘Network Manager Text User Interface‘, it is a text user interface which is used to configure hostname.
When we type nmtui command below window will appear
[root@cloud ~]# nmtui
Select “Set system hostname” and then click on OK..
Type the hostname whatever you want to set and then click on OK.
Restart the hostnamed service
[root@cloud ~]# systemctl restart systemd-hostnamed
[root@cloud ~]#
Verify new hostname using ‘hostname’ & ‘hostnamectl’ command

nmcli command :

nmcli is a command line utility for configuring and query hostname.
Check the hostname :
[root@cloud ~]# nmcli general hostname
[root@cloud ~]#
Change the hostname :
Syntax :
# nmcli general hostname
[root@cloud ~]# nmcli general hostname
Restart the hostnamed service using below systemctl command
[root@cloud ~]# systemctl restart systemd-hostnamed
[root@cloud ~]# hostname
[root@cloud ~]#
Note : hostnamectl command is recommended to query and configure hostname.

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