Centos install yum

rpm -Uhv http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

rpm -Uhv http://rpms.famillecollet.com/enterprise/remi-release-6.rpm

yum makecache

rpm -Uhv http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm

下载centos的yum

Centos 6 
wget http://mirrors.163.com/.help/CentOS6-Base-163.repo

Centos 7
wget http://mirrors.163.com/.help/CentOS7-Base-163.repo

Centos 5
wget http://mirrors.163.com/.help/CentOS5-Base-163.repo

Centos install yum

原文：http://blog.51cto.com/chaichuan/2094127