centos 7修改默认运行级别

查看当前的运行级别

编辑文件：

vim /etc/inittab

# inittab is no longer used when using systemd.
#
# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
#
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
#
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
#
# To view current default target, run:
# systemctl get-default
#
# To set a default target, run:
# systemctl set-default TARGET.target

通过文件，可以了解到，centos7有两种运行级别：
3：multi-user.target
5：graphical.target
查看当前的运行级别：systemctl get-default 命令
设置默认的启动级别：systemctl set-default TARGET.target

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

graphical.target表示当前的运行级别是图形界面。

设置默认的运行级别为mulit-user

[[email protected] ~]# 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.
[[email protected] ~]# systemctl get-default
multi-user.target
[[email protected] ~]# 

通过systemctl get-default查看到当前的运行级别为：multi-user.target，该命令重启以后生效。

切换当前的运行级别

systemctl isolate multi-user.target
systemctl isolate graphical.target

在不重启的情况下，切换运行级别