安装centos7的阿里源

安装centos7的阿里源的有效方案：

   1 curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo  
   
   2 yum clean all  
   
   3 yum makecache  
   
   4 yum install -y epel-release  
   
   5 yum repolist