在centos7系统中，安装了php+apache+mysql，然后也配置了虚拟目录做多个网站。需要解决的问题是：没有关闭selinux时php在网站根目录没有写入权限，站点根目录的权限设置了 777 也不行。只需要关闭selinux就可以了。

但是通常情况下载安装完CentOS7后，默认情况下SElinux是启用状态：

[root@localhos ~t]# sestatus 
SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
SELinux root directory:         /etc/selinux
Loaded policy name:             targeted
Current mode:                   permissive
Mode from config file:          enforcing
Policy MLS status:              enabled
Policy deny_unknown status:     allowed
Max kernel policy version:      28

如果要临时关闭，可以执行: setenforce 0

如果要永久关闭，可以修改配置文件/etc/selinux/config，将SELINU置为disabled。

[root@localhost ~]# cat /etc/selinux/config   
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
#SELINUX=enforcing
SELINUX=disabled
# SELINUXTYPE= can take one of three two values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected. 
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

修改完成后，保存重启