centos8替换阿里数据源

cd /etc/yum.repos.d
mv CentOS-Base.repo CentOS-Base.repo.bak
mv CentOS-Extras.repo CentOS-Extras.repo.bak
mv CentOS-centosplus.repo CentOS-centosplus.repo.bak
mv CentOS-PowerTools.repo CentOS-PowerTools.repo.bak
mv CentOS-AppStream.repo CentOS-AppStream.repo.bak
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-8.repo
yum makecache