Add networking documentation from issue #188. Refactor pod, label, and networking documentation to push details into separate documents. Add some documentation of how to connect to services.

docs/pods.md

@@ -0,0 +1,17 @@
+# Pods
+
+A _pod_ (as in a pod of whales or pea pod) is a relatively tightly coupled group of containers that are scheduled onto the same host. It models an application-specific "virtual host" in a containerized environment. Pods serve as units of scheduling, deployment, and horizontal scaling/replication, and share fate.
+
+In addition to defining the containers that run in the pod, the pod specifies a set of shared storage volumes. Pods facilitate data sharing and IPC among their constituents. In the future, they may share CPU and/or memory ([LPC2013](http://www.linuxplumbersconf.org/2013/ocw//system/presentations/1239/original/lmctfy%20(1).pdf)).
+
+The containers in the pod also all use the same network namespace/IP (and port space). The goal is for each pod have an IP address in a flat shared networking namespace that has full communication with other physical computers and containers across the network. [More details on networking](https://github.com/GoogleCloudPlatform/kubernetes/blob/master/docs/networking.md).
+
+While pods can be used to host vertically integrated application stacks, their primary motivation is to support co-located, co-managed helper programs, such as:
+- content management systems, file and data loaders, local cache managers, etc.
+- log and checkpoint backup, compression, rotation, snapshotting, etc.
+- data change watchers, log tailers, logging and monitoring adapters, event publishers, etc.
+- proxies, bridges, and adapters
+- controllers, managers, configurators, and updaters
+
+Individual pods are not intended to run multiple instances of the same application, in general.
+