How to Change HostName on Enterprise Linux 7

In CentOS 7, it is slightly different from CentOS 6 on changing hostname (How to Change HostName on Enterprise Linux 6.5). You don't have to modify /etc/sysconfig/network anymore, instead, you should modify a new file /etc/hostname.

There're 3 files need to be modified in order to change hostname.

1. The hostname file
[root@localhost ~]# vi /etc/hostname
primary01.example.com

2. The interface configuration file.
[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0
TYPE="Ethernet"
BOOTPROTO="none"
DEFROUTE="yes"
IPV4_FAILURE_FATAL="yes"
IPV6INIT="yes"
IPV6_AUTOCONF="yes"
IPV6_DEFROUTE="yes"
IPV6_FAILURE_FATAL="no"
NAME="eth0"
UUID="..."
ONBOOT="yes"
IPADDR0="10.12.13.123"
PREFIX0="8"
GATEWAY0="10.0.0.1"
DNS1="8.8.8.8"
DOMAIN="example.com"
HWADDR="..."
IPV6_PEERDNS="yes"
IPV6_PEERROUTES="yes"

3. The hosts file
[root@localhost ~]# vi /etc/hosts
127.0.0.1   primary01 primary01.example.com localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         primary01 primary01.example.com localhost localhost.localdomain localhost6 localhost6.localdomain6

Now, you can restart your server to verify the results.

Further reading -

How to Change DNS on Enterprise Linux 6.5