To set up the repository, install the webtatic-release RPM:

Webtatic EL7 for CentOS/RHEL 7:

rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm

Webtatic EL6 for CentOS/RHEL 6:

rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
rpm -Uvh https://mirror.webtatic.com/yum/el6/latest.rpm

还有个简便方法， 可以直接安装对应的epel源

yum -y install epel-release

查看源仓库的信息

 yum repolist

刷新本地缓存，实测epel的yum缓存下载较慢，耐心等待或者科学上网

yum makecache