Add docs on scheduler MultiPoint config

content/en/docs/reference/scheduling/config.md

@@ -78,6 +78,8 @@ extension points:
    least one bind plugin is required.
 1. `postBind`: This is an informational extension point that is called after
    a Pod has been bound.
+1. `multiPoint`: This is a config-only field that allows plugins to be enabled 
+   or disabled for all of their applicable extension points simultaneously.
 
 For each extension point, you could disable specific [default plugins](#scheduling-plugins)
 or enable your own. For example:
@@ -251,6 +253,186 @@ the same configuration parameters (if applicable). This is because the scheduler
 only has one pending pods queue.
 {{< /note >}}
 
+### Plugins that apply to multiple extension points {#multipoint}
+
+Starting from `kubescheduler.config.k8s.io/v1beta3`, there is an additional field in the 
+profile config, `multiPoint`, which allows for easily enabling or disabling a plugin 
+across several extension points. The intent of `multiPoint` config is to simplify the 
+configuration needed for users and administrators when using custom profiles.
+
+Consider a plugin, `MyPlugin`, which implements the `preScore`, `score`, `preFilter`, 
+and `filter` extension points. To enable `MyPlugin` for all its available extension 
+points, the profile config looks like:
+
+```yaml
+apiVersion: kubescheduler.config.k8s.io/v1beta3
+kind: KubeSchedulerConfiguration
+profiles:
+  - schedulerName: multipoint-scheduler
+    plugins:
+      multiPoint:
+        enabled:
+        - name: MyPlugin
+```
+
+This would equate to manually enabling `MyPlugin` for all of its extension 
+points, like so:
+
+```yaml
+apiVersion: kubescheduler.config.k8s.io/v1beta3
+kind: KubeSchedulerConfiguration
+profiles:
+  - schedulerName: non-multipoint-scheduler
+    plugins:
+      preScore:
+        enabled:
+        - name: MyPlugin
+      score:
+        enabled:
+        - name: MyPlugin
+      preFilter:
+        enabled:
+        - name: MyPlugin
+      filter:
+        enabled:
+        - name: MyPlugin
+```
+
+One benefit of using `multiPoint` here is that if `MyPlugin` implements another 
+extension point in the future, the `multiPoint` config will automatically enable it 
+for the new extension.
+
+Specific extension points can be excluded from `MultiPoint` expansion using 
+the `disabled` field for that extension point. This works with disabling default 
+plugins, non-default plugins, or with the wildcard (`'*'`) to disable all plugins. 
+An example of this, disabling `Score` and `PreScore`, would be:
+
+```yaml
+apiVersion: kubescheduler.config.k8s.io/v1beta3
+kind: KubeSchedulerConfiguration
+profiles:
+  - schedulerName: non-multipoint-scheduler
+    plugins:
+      multiPoint:
+        enabled:
+        - name: 'MyPlugin'
+      preScore:
+        disabled:
+        - name: '*'
+      score:
+        disabled:
+        - name: '*'
+```
+
+In `v1beta3`, all [default plugins](#scheduling-plugins) are enabled internally through `MultiPoint`. 
+However, individual extension points are still available to allow flexible 
+reconfiguration of the default values (such as ordering and Score weights). For 
+example, consider two Score plugins `DefaultScore1` and `DefaultScore2`, each with 
+a weight of `1`. They can be reordered with different weights like so:
+
+```yaml
+apiVersion: kubescheduler.config.k8s.io/v1beta3
+kind: KubeSchedulerConfiguration
+profiles:
+  - schedulerName: multipoint-scheduler
+    plugins:
+      score:
+        enabled:
+        - name: 'DefaultScore2'
+          weight: 5
+```
+
+In this example, it's unnecessary to specify the plugins in `MultiPoint` explicitly 
+because they are default plugins. And the only plugin specified in `Score` is `DefaultScore2`.
+This is because plugins set through specific extension points will always take precedence 
+over `MultiPoint` plugins. So, this snippet essentially re-orders the two plugins 
+without needing to specify both of them.
+
+The general hierarchy for precedence when configuring `MultiPoint` plugins is as follows:
+1. Specific extension points run first, and their settings override whatever is set elsewhere
+2. Plugins manually configured through `MultiPoint` and their settings
+3. Default plugins and their default settings
+
+To demonstrate the above hierarchy, the following example is based on these plugins:
+|Plugin|Extension Points|
+|---|---|
+|`DefaultQueueSort`|`QueueSort`|
+|`CustomQueueSort`|`QueueSort`|
+|`DefaultPlugin1`|`Score`, `Filter`|
+|`DefaultPlugin2`|`Score`|
+|`CustomPlugin1`|`Score`, `Filter`|
+|`CustomPlugin2`|`Score`, `Filter`|
+
+A valid sample configuration for these plugins would be:
+
+```yaml
+apiVersion: kubescheduler.config.k8s.io/v1beta3
+kind: KubeSchedulerConfiguration
+profiles:
+  - schedulerName: multipoint-scheduler
+    plugins:
+      multiPoint:
+        enabled:
+        - name: 'CustomQueueSort'
+        - name: 'CustomPlugin1'
+          weight: 3
+        - name: 'CustomPlugin2'
+        disabled:
+        - name: 'DefaultQueueSort'
+      filter:
+        disabled:
+        - name: 'DefaultPlugin1'
+      score:
+        enabled:
+        - name: 'DefaultPlugin2'
+```
+
+Note that there is no error for re-declaring a `MultiPoint` plugin in a specific 
+extension point. The re-declaration is ignored (and logged), as specific extension points 
+take precedence.
+
+Besides keeping most of the config in one spot, this sample does a few things:
+* Enables the custom `queueSort` plugin and disables the default one
+* Enables `CustomPlugin1` and `CustomPlugin2`, which will run first for all of their extension points
+* Disables `DefaultPlugin1`, but only for `filter`
+* Reorders `DefaultPlugin2` to run first in `score` (even before the custom plugins)
+
+In versions of the config before `v1beta3`, without `multiPoint`, the above snippet would equate to this:
+```yaml
+apiVersion: kubescheduler.config.k8s.io/v1beta2
+kind: KubeSchedulerConfiguration
+profiles:
+  - schedulerName: multipoint-scheduler
+    plugins:
+
+      # Disable the default QueueSort plugin
+      queueSort:
+        enabled:
+        - name: 'CustomQueueSort'
+        disabled:
+        - name: 'DefaultQueueSort'
+
+      # Enable custom Filter plugins
+      filter:
+        enabled:
+        - name: 'CustomPlugin1'
+        - name: 'CustomPlugin2'
+        - name: 'DefaultPlugin2'
+        disabled:
+        - name: 'DefaultPlugin1'
+
+      # Enable and reorder custom score plugins
+      score:
+        enabled:
+        - name: 'DefaultPlugin2'
+          weight: 1
+        - name: 'DefaultPlugin1'
+          weight: 3
+```
+
+While this is a complicated example, it demonstrates the flexibility of `MultiPoint` config 
+as well as its seamless integration with the existing methods for configuring extension points.
+
 ## Scheduler configuration migrations
 
 {{< tabs name="tab_with_md" >}}