使用dnf下载与安装网络源的rpm:
dnf download \--releasever=2.1903 \--disablerepo="*" \--resolve \--alldeps \--repofrompath=ali-os,http://mirrors.aliyun.com/alinux/2.1903/os/x86_64/ \--repofrompath=ali-plus,http://mirrors.aliyun.com/alinux/2.1903/plus/x86_64/ \--destdir="/tmp/c8t"