Update health check docs regarding containerPort
@@ -66,6 +66,8 @@ You can confirm the health check endpoint point it's using one of 2 ways:
## Limitations
A few points to note:
+* The pod's `containerPort` field must be defined
+* The service's `targetPort` field must point to the pod port's `containerPort` value or `name`. Note that the `targetPort` defaults to the `port` value if not defined
* The readiness probe must be exposed on the port matching the `servicePort` specified in the Ingress
* The readiness probe cannot have special requirements like headers
* The probe timeouts are translated to GCE health check timeouts
