运行yum报错
CentOS Linux 8 - AppStream 80 B/s | 38 B 00:00 错误:为仓库 'appstream' 下载元数据失败 : Cannot prepare internal mirrorlist: No URLs in mirrorlist
mv /etc/yum.repos.d/ /etc/yum.repos.d_bak
mkdir /etc/yum.repos.d
curl -O https://vault.centos.org/centos/8/AppStream/x86_64/os/Packages/wget-1.19.5-10.el8.x86_64.rpm
curl -O https://vault.centos.org/centos/8/BaseOS/x86_64/os/Packages/libmetalink-0.1.3-7.el8.x86_64.rpm
rpm -ivh libmetalink-0.1.3-7.el8.x86_64.rpm
rpm -ivh wget-1.19.5-10.el8.x86_64.rpm
cd /etc/yum.repos.d
wget http://mirrors.aliyun.com/repo/Centos-8.repo
yum clean all
yum makecache
OK