Set default run 3.5.3 constituency
Centos7 no longer USES the/etc/inittab file to the default start level configuration, and use more freedom than sysvinit runlevel target alternative,
Runlevels 3 with multi - user. Target replacement,
Runlevel 5 with graphical target replacement,

Set the default start level 3
/root @ xuegod63 ~ # systemctl set - the default multi - user. Target
Set the default start level 5
/root @ xuegod63 ~ # systemctl set - the default graphical. The target

/root @ xuegod63 ~ # runlevel
3 # 5 according to switch from level 3 to 5 level
View the current default start level
/root @ xuegod63 ~ # systemctl get - the default
Graphical. Target