更换安装源
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
或者
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
CentOS No package nginx available.
yum install epel-release
403权限问题解决
user改为你的用户名,我是root登录,所以就是root