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 |