centos 8.5.2111换源：换阿里源

rename '.repo' '.repo.bak' /etc/yum.repos.d/*.repo

wget http://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo -O /etc/yum.repos.d/Centos-vault-8.5.2111.repo

wget http://mirrors.aliyun.com/repo/epel-archive-8.repo -O /etc/yum.repos.d/epel-archive-8.repo

yum clean all && yum makecache