How to set up a linux / virtualbox / pfSense system where all networking runs over pfSense and apps are run in Virtualbox VMs, each firewalled by pfSense separately, with some i3 monitoring of the VMs
http://www.woodensquares.net/posts/rationale.html
Set up a Kubernetes cluster from scratch on a set of CoreOS Xen guests, with flannel, RBAC, TLS etc.
http://www.woodensquares.net/posts/xen-1.html