Fix controller glossary entries

Author: sftim

content/en/docs/reference/glossary/controller.md

@@ -11,4 +11,20 @@ tags:
 - architecture
 - fundamental
 ---
- A control loop that watches the shared state of the cluster through the {{< glossary_tooltip text="apiserver" term_id="kube-apiserver" >}} and makes changes attempting to move the current state towards the desired state.
+In Kubernetes, controllers are control loops that watch the state of your
+{{< glossary_tooltip term_id="cluster" text="cluster">}}, then make or request
+changes where needed.
+Each controller tries to move the current cluster state closer to the desired
+state.
+
+<!--more-->
+
+Controllers watch the shared state of your cluster through the
+{{< glossary_tooltip text="apiserver" term_id="kube-apiserver" >}} (part of the
+{{< glossary_tooltip term_id="control-plane" >}}).
+
+Some controllers also run inside the control plane, providing control loops that
+are core to Kubernetes' operations. For example: the deployment controller, the
+daemonset controller, the namespace controller, and the persistent volume
+controller (and others) all run within the
+{{< glossary_tooltip term_id="kube-controller-manager" >}}.

content/en/docs/reference/glossary/kube-controller-manager.md

@@ -2,7 +2,7 @@
 title: kube-controller-manager
 id: kube-controller-manager
 date: 2018-04-12
-full_link: /docs/reference/generated/kube-controller-manager/
+full_link: /docs/reference/command-line-tools-reference/kube-controller-manager/
 short_description: >
   Component on the master that runs controllers.
 
@@ -13,7 +13,6 @@ tags:
 ---
  Component on the master that runs {{< glossary_tooltip text="controllers" term_id="controller" >}}.
 
-<!--more--> 
+<!--more-->
 
 Logically, each {{< glossary_tooltip text="controller" term_id="controller" >}} is a separate process, but to reduce complexity, they are all compiled into a single binary and run in a single process.
-

content/en/docs/reference/glossary/statefulset.md

@@ -18,6 +18,3 @@ tags:
 <!--more--> 
 
 Like a {{< glossary_tooltip term_id="deployment" >}}, a StatefulSet manages Pods that are based on an identical container spec. Unlike a Deployment, a StatefulSet maintains a sticky identity for each of their Pods. These pods are created from the same spec, but are not interchangeable&#58; each has a persistent identifier that it maintains across any rescheduling.
-
-A StatefulSet operates under the same pattern as any other Controller. You define your desired state in a StatefulSet *object*, and the StatefulSet *controller* makes any necessary updates to get there from the current state.
-