Centos7 修改yum源为阿里云

1.备份原来的yum文件

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo_bak

2.下载阿里云yum配置到    /etc/yum.repos.d/

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

3.更新

yum makecache

yum -y update

           ...等待完成