centos7 修改yum源为阿里源
# 备份旧配置信息
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak
# 下载阿里云源
wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo
# 更新yum源
yum makecache
yum repolist
原文：https://www.cnblogs.com/sivanchan/p/14737510.html