一 、更换阿里镜像
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup && \
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo && \
yum makecache
二、更换中科大镜像站
sudo sed -e ‘s|^mirrorlist=|#mirrorlist=|g‘ -e ‘s|^#baseurl=http://mirror.centos.org/centos|baseurl=https://mirrors.ustc.edu.cn/centos|g‘ -i.bak /etc/yum.repos.d/CentOS-Base.repo yum makecache
原文：https://www.cnblogs.com/shwang/p/12585128.html