Merge master into dev-1.21 to keep in sync, plus latest API reference

This sync merge includes API reference updates.

content/en/docs/concepts/scheduling-eviction/assign-pod-node.md

@@ -11,18 +11,17 @@ weight: 20
 
 <!-- overview -->
 
-You can constrain a {{< glossary_tooltip text="Pod" term_id="pod" >}} to only be able to run on particular 
-{{< glossary_tooltip text="Node(s)" term_id="node" >}}, or to prefer to run on particular nodes.
-There are several ways to do this, and the recommended approaches all use
-[label selectors](/docs/concepts/overview/working-with-objects/labels/) to make the selection.
+You can constrain a {{< glossary_tooltip text="Pod" term_id="pod" >}} so that it can only run on particular set of
+{{< glossary_tooltip text="Node(s)" term_id="node" >}}.
+There are several ways to do this and the recommended approaches all use
+[label selectors](/docs/concepts/overview/working-with-objects/labels/) to facilitate the selection.
 Generally such constraints are unnecessary, as the scheduler will automatically do a reasonable placement
-(e.g. spread your pods across nodes, not place the pod on a node with insufficient free resources, etc.)
-but there are some circumstances where you may want more control on a node where a pod lands, for example to ensure
+(e.g. spread your pods across nodes so as not place the pod on a node with insufficient free resources, etc.)
+but there are some circumstances where you may want to control which node the pod deploys to - for example to ensure
 that a pod ends up on a machine with an SSD attached to it, or to co-locate pods from two different
 services that communicate a lot into the same availability zone.
 
 
-
 <!-- body -->
 
 ## nodeSelector

content/en/docs/concepts/scheduling-eviction/kube-scheduler.md

@@ -87,6 +87,7 @@ of the scheduler:
 * Read about [scheduler performance tuning](/docs/concepts/scheduling-eviction/scheduler-perf-tuning/)
 * Read about [Pod topology spread constraints](/docs/concepts/workloads/pods/pod-topology-spread-constraints/)
 * Read the [reference documentation](/docs/reference/command-line-tools-reference/kube-scheduler/) for kube-scheduler
+* Read the [kube-scheduler config (v1beta1)](/docs/reference/config-api/kube-scheduler-config.v1beta1/) reference
 * Learn about [configuring multiple schedulers](/docs/tasks/extend-kubernetes/configure-multiple-schedulers/)
 * Learn about [topology management policies](/docs/tasks/administer-cluster/topology-manager/)
 * Learn about [Pod Overhead](/docs/concepts/scheduling-eviction/pod-overhead/)
@@ -94,3 +95,4 @@ of the scheduler:
   * [Volume Topology Support](/docs/concepts/storage/storage-classes/#volume-binding-mode)
   * [Storage Capacity Tracking](/docs/concepts/storage/storage-capacity/)
   * [Node-specific Volume Limits](/docs/concepts/storage/storage-limits/)
+

content/en/docs/concepts/scheduling-eviction/scheduler-perf-tuning.md

@@ -24,8 +24,6 @@ in a process called _Binding_.
 This page explains performance tuning optimizations that are relevant for
 large Kubernetes clusters.
 
-
-
 <!-- body -->
 
 In large clusters, you can tune the scheduler's behaviour balancing
@@ -44,8 +42,10 @@ should use its compiled-in default.
 If you set `percentageOfNodesToScore` above 100, kube-scheduler acts as if you
 had set a value of 100.
 
-To change the value, edit the kube-scheduler configuration file (this is likely
-to be `/etc/kubernetes/config/kube-scheduler.yaml`), then restart the scheduler.
+To change the value, edit the
+[kube-scheduler configuration file](/docs/reference/config-api/kube-scheduler-config.v1beta1/)
+and then restart the scheduler.
+In many cases, the configuration file can be found at `/etc/kubernetes/config/kube-scheduler.yaml`.
 
 After you have made this change, you can run
 
@@ -99,7 +99,6 @@ algorithmSource:
 percentageOfNodesToScore: 50
 ```
 
-
 ## Tuning percentageOfNodesToScore
 
 `percentageOfNodesToScore` must be a value between 1 and 100 with the default
@@ -160,4 +159,7 @@ Node 1, Node 5, Node 2, Node 6, Node 3, Node 4
 
 After going over all the Nodes, it goes back to Node 1.
 
+## {{% heading "whatsnext" %}}
+
+* Check the [kube-scheduler configuration reference (v1beta1)](/docs/reference/config-api/kube-scheduler-config.v1beta1/)