CentOS7的运行级别

一 查看当前运行的级别

[root@localhost ~]# runlevel

N 5

二 运行级别概念

第三运行级：

multi-user.target

第五运行级：

graphical.target

前者是符号链接指向了后面的target

runlevel3.target -> multi-user.target

runlevel5.target -> graphical.target

三 运行级别的切换

切换到：运行级3

下面这方法可以

systemctl isolate multi-user.target

举例

[root@localhost ~]# systemctl isolate multi-user.target

PolicyKit daemon disconnected from the bus.

We are no longer a registered authentication agent.

[root@localhost ~]# runlevel

5 3

切换到：运行级5

下面方法可以

systemctl isolate graphical.target

[root@localhost ~]# systemctl isolate graphical.target

PolicyKit daemon disconnected from the bus.

We are no longer a registered authentication agent.

PolicyKit daemon reconnected to bus.

Attempting to re-register as an authentication agent.

We are now a registered authentication agent.

[root@localhost ~]# runlevel

3 5

四 修改开机默认运行级别

切换到运行级3

systemctl set-default multi-user.target

[root@localhost ~]# systemctl set-default multi-user.target

Removed symlink /etc/systemd/system/default.target.

Created symlink from /etc/systemd/system/default.target to /usr/lib/systemd/system/multi-user.target.

切换到运行级5

systemctl set-default graphical.target

[root@localhost ~]# systemctl set-default graphical.target

Removed symlink /etc/systemd/system/default.target.

Created symlink from /etc/systemd/system/default.target to /usr/lib/systemd/system/graphical.target.