Change the HostName of CentOS 8

There are three classes of hostname: static, pretty, and transient.
static - The traditional hostname. It is stored in the /etc/hostname file and can be set by the user.
pretty - A free-form UTF8 hostname used for presentation to the user. For example, Rusking's desktop.
transient - A dynamic hostname that is maintained by the kernel. DHCP or mDNS servers can change the transient hostname at run time. By default, it is the same as the static hostname.

It is recommended to use a fully-qualified domain name (FQDN ) for both static and transient names such as host.example.com.

1. 查看当前主机的hostname

[root@centos8 ~]# hostnamectl
Static hostname: centos8
Icon name: computer-vm
Chassis: vm
Machine ID: 611133c4577f4388a7892c32df056c74
Boot ID: 7376f5f7f2314132a3f3f7ec0aeee06d
Virtualization: oracle
Operating System: CentOS Linux 8 (Core)
CPE OS Name: cpe:/o:centos:centos:8
Kernel: Linux 4.18.0-193.el8.x86_64
Architecture: x86-64

[root@centos8 ~]# cat /etc/hostname
centos8
[root@centos8 ~]# hostnamectl --static
centos8
[root@centos8 ~]# hostnamectl --transient
centos8
[root@centos8 ~]# hostnamectl --pretty

2. 修改主机名
[root@centos8 ~]# hostnamectl set-hostname centos8.test.com --static （不加static也可以，默认就是static。）
[root@centos8 ~]# hostnamectl set-hostname "rusking's Test CentOS8" --pretty
[root@centos8 ~]# hostnamectl set-hostname centos8.test.com --transient
[root@centos8 ~]# hostnamectl --static
centos8.test.com
[root@centos8 ~]# hostnamectl --pretty
rusking's Test CentOS8
[root@centos8 ~]# hostnamectl --transient
centos8.test.com
[root@centos8 ~]# hostnamectl
Static hostname: centos8.test.com
Pretty hostname: rusking's Test CentOS8
Icon name: computer-vm
Chassis: vm
Machine ID: 611133c4577f4388a7892c32df056c74
Boot ID: 7376f5f7f2314132a3f3f7ec0aeee06d
Virtualization: oracle
Operating System: CentOS Linux 8 (Core)
CPE OS Name: cpe:/o:centos:centos:8
Kernel: Linux 4.18.0-193.el8.x86_64
Architecture: x86-64

3. 也可以在nmtui界面修改。

[root@centos8 ~]# nmtui

输入nmtui命令后，出现如下界面，选择“Set system hostname". 

                                                     ┌─┤ NetworkManager TUI ├──┐
                                                     │                         │
                                                     │ Please select an option │
                                                     │                         │
                                                     │ Edit a connection       │
                                                     │ Activate a connection   │
                                                     │ Set system hostname     │
                                                     │                         │
                                                     │ Quit                    │
                                                     │                         │
                                                     │                    <OK> │
                                                     │                         │
                                                     └─────────────────────────┘

设置完成之后，需要重启systemd-hostnamed.service生效。 

[root@centos8 ~]# systemctl restart systemd-hostnamed.service 

上述两种方式修改完主机名之后，/etc/hostname会自动更新。但是需要手动检查并修改/etc/hosts文件中配置的hostname。