Update kubelet overview help doc

cmd/kubelet/app/server.go

@@ -118,7 +118,10 @@ func NewKubeletCommand(stopCh <-chan struct{}) *cobra.Command {
 	cmd := &cobra.Command{
 		Use: componentKubelet,
 		Long: `The kubelet is the primary "node agent" that runs on each
-node. The kubelet works in terms of a PodSpec. A PodSpec is a YAML or JSON object
+node. It can register the node with the apiserver using one of: the hostname; a flag to
+override the hostname; or specific logic for a cloud provider.
+
+The kubelet works in terms of a PodSpec. A PodSpec is a YAML or JSON object
 that describes a pod. The kubelet takes a set of PodSpecs that are provided through
 various mechanisms (primarily through the apiserver) and ensures that the containers
 described in those PodSpecs are running and healthy. The kubelet doesn't manage