Centos7默认yum源为阿里云源

1、加载wget环境

 yum install wget -y

2、备份本地yum源

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

3、下载新的CentOS-Base.repo 到/etc/yum.repos.d/

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

4、生存缓存

yum clean all
yum makecache

5、查看yum源

yum repolist