mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
mv -f /etc/yum.repos.d/*.repo
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
sudo yum clean all
sudo yum makecache
方法二:
bash <(curl -skL sh.dwvps.com/LinuxTools/CNyum.sh)