This article explains how to install NginX and PHP-FPM 5.3 on an OpenShift server. Note that the OpenShift node(s) must have software installed to allow this.
On the node:
yum install nginx php-fpm
And from the workstation using RHC:
rhc app create phpapp -s https://reflector-getupcloud.getup.io/reflect?github=getupcloud/openshift-nginx-php-fpm