安装过程很简单
Centos 7下执行如下命令：
rpm -ivh http://mirrors.kernel.org/fedora-epel/7/x86_64/e/epel-release-7-10.noarch.rpm
Centos 6下执行如下命令：
rpm -ivhhttp://mirrors.kernel.org/fedora-epel/6/i386/epel-release-6-8.noarch.rpm
或者
rpm -ivh http://mirrors.kernel.org/fedora-epel/6/x86_64/epel-release-6-8.noarch.rpm
安装完成后，使用如下命令查看是否安装成功
yum repolist