cd /etc/yum.repos.d/mv CentOS-Base.repo CentOS-Base.repo.backup下載阿里云的yum源
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo運行
yum makecache參考：http://mirrors.aliyun.com/help/centos