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
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