1.windows下用cmd命令SSH链接服务器
ssh root@xxx.xxx.xxx.79
2.先备份原服务器yum
sudo cp -r /etc/yum.repos.d /etc/yum.repos.d.backup
3.删除yum源
sudo rm -f /etc/yum.repos.d/CentOS-Base.repo
4.下载阿里源
sudo curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo
5.更新缓存
sudo yum clean all sudo yum makecache
6.验证yum
yum repolist
