Actually, it's incredibly easy, especially in tandem with CentOS Atomic Host. Here's my setup at work I just deployed last month:
osm01-03 - OpenShift masters, don't run anything other than OpenShift services (Atomic host)
osn01-03 - OpenShift nodes, actually run the apps (Atomic host)
osnlb - Load balancer for the master (CentOS 7)
oss - NFS server providing storage for OpenShift docker images (CentOS 7)
On your storage node make sure /exports is on a separate filesystem with adequate storage to store your container images, it will be set up automatically from there.
Once you have these couple servers spun up (You can skip the multiple masters + load balancer if you don't care about HA, though I recommend it) from a CentOS box you want to deploy from make sure you push an SSH key out to all the servers for root access then run the following.
yum install centos-release-openshift-origin
yum --enablerepo=centos-openshift-origin-testing install atomic-openshift-utils
atomic-openshift-installer install
Walk through the installer, making sure you pick "OpenShift Origin" to install the upstream (non-commercial) build, say "container-based" for every atomic system you have, and tell it which are your HAProxy (load balancer) and Storage servers, plus what your default domain will be (I recommend using either a subdomain of your existing corporate domain, or buying a new one for openshift use). After you're done specifying your configuration it will generate an ansible playbook and stash it in ~/.config/openshift and start building your cluster out. Once it's done you just need to set up your DNS entries (whatever your master hostname is should point at your load balancer, then I recommend you add a wildcard DNS entry for whatever domain you chose and point it at all of your nodes). The last thing you'll need to do is configure authentication [1] as by default it will take any username/password combo, and setup the default builder images [2]
[1]: https://docs.openshift.com/enterprise/3.0/admin_guide/config...
[2]: https://docs.openshift.com/enterprise/3.0/install_config/ins...
Sorry for the wall of text, I spent two days figuring this out myself - but after a month in production my team is loving OpenShift and we've already deployed three greenfield apps on it. It's getting a lot more love than I ever expected, and I'm already looking at needing to give my node VM's more resources. Feel free to email me at the address in my profile if you have any questions.