1.进入到源文件路径
cd /etc/yum.repos.d/
2.下载163源
curl -O http://mirrors.163.com/.help/CentOS7-Base-163.repo
3.备份之前源
mv CentOS-Base.repo CentOS-Base.repo.bak
4.163源名字修改
mv CentOS7-Base-163.repo CentOS-Base.repo
5.清除缓存
yum clean all
6.更新本地yum缓存
yum makecache