163yum源：http://mirrors.163.com/.help/centos.html

1、首先备份/etc/yum.repos.d/CentOS-Base.repo

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

2、下载对应版本repo文件, 放入/etc/yum.repos.d/(操作前请做好相应备份)

• CentOS7
• CentOS6
• CentOS5

3、运行以下命令生成缓存

yum clean all

yum makecache