centos7更换阿里云yum源

1.备份原yum源

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

2.下载阿里云yum源

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

3.清除缓存

yum clean all

4.新缓存

yum makecache

5.更新

yum update