论断一：

今天装了下正式版的RHEL7，发现熟悉的inittab中没有了修改默认运行级别，打开inittab如下

[root@localhost init.d]# vi /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 /etc/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 set a default target, run:
#
# ln -sf /lib/systemd/system/.target /etc/systemd/system/default.target

中间没有了熟悉的 id:5:initdefault

 

RHEL7 使用systemd创建符号链接指向默认运行级别。

 

修改方法为：
1.首先删除已经存在的符号链接
----------------------------------------------------------------------------------
rm /etc/systemd/system/default.target
----------------------------------------------------------------------------------
2.默认级别转换为3(文本模式)
----------------------------------------------------------------------------------
ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target
----------------------------------------------------------------------------------
或者默认级别转换为5(图形模式)
----------------------------------------------------------------------------------
ln -sf /lib/systemd/system/graphical.target /etc/systemd/system/default.target
----------------------------------------------------------------------------------
3.重启
----------------------------------------------------------------------------------
reboot
-----------------------------------------------------------------------------


论断二：

Red Hat Enterprise Linux Server release 7.0 (Maipo) 修改启动级别
之前的配置文件在/etc/inittab 这里
vim /etc/inittab 我们服务器用，习惯把id:5改成3，字符界面启动，或者最小化安装。
rhel7.0 做了很多大的改变，打开inittab看下
# inittab is no longer used when using systemd.      /etc/inittab 这个文件已经不再使用 
# inittab is no longer used when using systemd.
#
# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# Ctrl-Alt-Delete is handled by /etc/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      类似于运行级别3
# graphical.target: analogous to runlevel 5       类似于运行级别5
#
# To set a default target, run:               #运行下面 命令设置默认开机启动级别
#
# ln -sf /lib/systemd/system/.target /etc/systemd/system/default.target

 /lib/systemd/system/   里面有0-6 六个级别的文件软连接
runlevel0.target         poweroff
runlevel1.target         rescue
runlevel2.target         multi-user
runlevel3.target         multi-user
runlevel4.target         multi-user
runlevel5.target         graphical
runlevel6.target         reboot
例如：修改5级别： ln -sf /lib/systemd/system/runlevel5.target   /etc/systemd/system/default.target
例如：修改3级别： ln -sf /lib/systemd/system/runlevel3.target   /etc/systemd/system/default.target