CentOS 8.5 yum源更新（阿里云）

查看版本号

cat /etc/redhat-release

cd /etc/yum.repos.d/
mkdir back && mv CentOS* back/
wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo
yum clean all && yum makecache