新系统centos6.5，按照之前的方法安装epel源：
http://opswill.com/articles/apache-rRedirecting-base-on-geoip.html

后无论安装什么软件都会报错：

[root@localhost ~]# yum install ansible Loaded plugins: fastestmirror,
refresh-packagekit, security Loading mirror speeds from cached
hostfile Error: Cannot retrieve metalink for repository: epel. Please
verify its path and try again

google了一下，解决方法：
编辑：/etc/yum.repos.d/epel.repo
将所有的

#baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch       mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch

取消所有的baseurl的注释，并注释掉mirrorlist即可。
之后 yum makecache.

参考文章：
http://www.rackspace.com/knowledge_center/article/installing-rhel-epel-repo-on-centos-5x-or-6x
http://teddysun.com/153.html