~ *Write as you go documentation of setting up a Raspberry Pi farm.* ~
1. Assemble the Pi 2 rig.
Naming of the machines, top to bottom
.1 continental 
.2 coralina
.3 isla
.4 sedimentario
.5 fluvial
Explorations
Of course no exploration comes without drawbacks. In our research we found out about Docker Swarm's Discovery Backends , which unfortunately defaults to a hosted web service.
Earlier on we already discovered a Hypriot version of Consul , but not much documentation to it.
So, what is Consul ?
Scott Lowe wrote a quick introduction to consul .
Scott Lowe also wrote about running a small Docker Swarm cluster with the help of Consul.
But how do these scenarios apply within our Raspberry Pi environment?
a self-contained Cloud-in-a-Box
Fortunately someone else already explored these directions for us. We just have to infer the knowledge from all different sources.
Swarming Raspberry Pi - Part 2 Registry Mirror + GitHub repositories for RPI Consul, Registrator and Swarm
Swarming Raspberry Pi Docker Swarm discovery options
Swarming Raspberry Pi private registries for Swarm images
Conclusion
A basic Docker cluster is set up via a couple of Raspberry Pis. A Private Registry + Mirror is advisable for local deployments.