centos7修改默认运行级别

一、centos6是通过修改/etc/inittab来修改默认运行级别的：

[root@localhost ~]# vim /etc/inittab

二、在centos7下运行vim /etc/inittab结果如下：

[root@centos7 ~]# cat /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  相当于 runlevel 3
# graphical.target: analogous to runlevel 5   相当于 runlevel 5
#
# To view current default target, run:
# systemctl get-default --------------------- 获取当前运行级别
#
# To set a default target, run:
# systemctl set-default TARGET.target ------- 设置运行级别
#

可以看到，里面除了注释，什么也没有，并没有centos6中设置默认运行级别的方式。

三、CentOS 7.x 查看默认运行级别的方式为

方式1
[root@centos7 ~]# runlevel
5 3


方式2
[root@centos7 ~]# systemctl get-default
multi-user.target

四、CentOS 7.x 设置默认运行级别命令：
       [root@centos7 ~]# systemctl set-default TARGET.target

[root@centos7 ~]# systemctl set-default multi-user.target --------> 设置为runlevel 3
Removed symlink /etc/systemd/system/default.target.
Created symlink from /etc/systemd/system/default.target to /usr/lib/systemd/system/multi-user.target.

五、CentOS 7.x 运行级别 TARGET.target 对应表

init级别	systemctl target
0	shutdown.target
1	emergency.target
2	rescure.target
3	multi-user.target
4	无
5	graphical.target
6	无