add introductions for scheduler component config api migrations

Signed-off-by: kerthcet <kerthcet@gmail.com>

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

@@ -20,8 +20,7 @@ by implementing one or more of these extension points.
 
 You can specify scheduling profiles by running `kube-scheduler --config <filename>`,
 using the
-KubeSchedulerConfiguration ([v1beta1](/docs/reference/config-api/kube-scheduler-config.v1beta1/)
-or [v1beta2](/docs/reference/config-api/kube-scheduler-config.v1beta2/)) 
+KubeSchedulerConfiguration ([v1beta2](/docs/reference/config-api/kube-scheduler-config.v1beta2/))
 struct.
 
 A minimal configuration looks as follows:
@@ -89,7 +88,7 @@ profiles:
   - plugins:
       score:
         disabled:
-        - name: NodeResourcesLeastAllocated
+        - name: PodTopologySpread
         enabled:
         - name: MyCustomPluginA
           weight: 2
@@ -100,7 +99,7 @@ profiles:
 You can use `*` as name in the disabled array to disable all default plugins
 for that extension point. This can also be used to rearrange plugins order, if
 desired.
-   
+
 ### Scheduling plugins
 
 The following plugins, enabled by default, implement one or more of these
@@ -116,10 +115,6 @@ extension points:
   Extension points: `filter`.
 - `NodePorts`: Checks if a node has free ports for the requested Pod ports.
   Extension points: `preFilter`, `filter`.
-- `NodePreferAvoidPods`: Scores nodes according to the node
-  {{< glossary_tooltip text="annotation" term_id="annotation" >}}
-  `scheduler.alpha.kubernetes.io/preferAvoidPods`.
-  Extension points: `score`.
 - `NodeAffinity`: Implements
   [node selectors](/docs/concepts/scheduling-eviction/assign-pod-node/#nodeselector)
   and [node affinity](/docs/concepts/scheduling-eviction/assign-pod-node/#node-affinity).
@@ -170,7 +165,7 @@ extension points:
   Extension points: `bind`.
 - `DefaultPreemption`: Provides the default preemption mechanism.
   Extension points: `postFilter`.
-  
+
 You can also enable the following plugins, through the component config APIs,
 that are not enabled by default:
 
@@ -182,31 +177,7 @@ that are not enabled by default:
 - `CinderLimits`: Checks that [OpenStack Cinder](https://docs.openstack.org/cinder/)
   volume limits can be satisfied for the node.
   Extension points: `filter`.
-
-The following plugins are deprecated and can only be enabled in a `v1beta1`
-configuration:
 
-- `NodeResourcesLeastAllocated`: Favors nodes that have a low allocation of
-  resources.
-  Extension points: `score`.
-- `NodeResourcesMostAllocated`: Favors nodes that have a high allocation of
-  resources.
-  Extension points: `score`.
-- `RequestedToCapacityRatio`: Favor nodes according to a configured function of
-  the allocated resources.
-  Extension points: `score`.
-- `NodeLabel`: Filters and / or scores a node according to configured
-  {{< glossary_tooltip text="label(s)" term_id="label" >}}.
-  Extension points: `filter`, `score`.
-- `ServiceAffinity`: Checks that Pods that belong to a
-  {{< glossary_tooltip term_id="service" >}} fit in a set of nodes defined by
-  configured labels. This plugin also favors spreading the Pods belonging to a
-  Service across nodes.
-  Extension points: `preFilter`, `filter`, `score`.
-- `NodePreferAvoidPods`: Prioritizes nodes according to the node annotation
-  `scheduler.alpha.kubernetes.io/preferAvoidPods`.
-  Extension points: `score`.
-
 ### Multiple profiles
 
 You can configure `kube-scheduler` to run more than one profile.
@@ -255,10 +226,30 @@ the same configuration parameters (if applicable). This is because the scheduler
 only has one pending pods queue.
 {{< /note >}}
 
+## Migration introductions between api versions
+
+### v1beta2 -> v1beta3
+* Some plugins' weight has been modified for user preferences:
+  * `InterPodAffinity` to 2
+  * `NodeAffinity` to 2
+  * `TaintToleration` to 3
+* Support for configuration file version `v1beta1` is removed.
+* Scheduler plugin `ServiceAffinity` is removed.
+* The legacy scheduler policy config is removed, the associated flags `policy-config-file`, `policy-configmap`, `policy-configmap-namespace` and `use-legacy-policy-config` are also removed.
+
+### v1beta1 -> v1beta2
+* A new score extension for `NodeResourcesFit` plugin is introduced, it merges the functionalities of `NodeResourcesLeastAllocated`, `NodeResourcesMostAllocated` and `RequestedToCapacityRatio` plugins, which are marked as deprecated is v1beta2. In v1beta1, the three plugins can still be used but not at the same time with the score extension of `NodeResourcesFit`.
+* Scheduler plugin `NodeLabel` is deprecated, it's only configurable through the scheduler policy API and v1beta1 component config API. It's recommended to use `NodeAffinity` plugin instead.
+* Scheduler plugin `ServiceAffinity` is deprecated, it's only configurable through the scheduler policy API and v1beta1 component config API. It's recommended to use `InterPodAffinity` plugin instead.
+* Scheduler plugin `NodePreferAvoidPods` is deprecated, it's only configurable through the scheduler policy API and v1beta1 component config API. It's recommended to use node taints instead.
+* A plugin enabled in a v1beta2 configuration file takes precedence over the default configuration for that plugin. This simplifies enabling default plugins with custom configuration without the necessary to explicitly disable those default plugins.
+* New parameter `defaultingType` added for `PodTopologySpread` plugin allowing to use k8s defined or user provided default constraints.
+* Add pre-checks for scheduler healthz and metrics bind address.
+* The deprecated CLI flags `--hard-pod-affinity-symmetric-weight`, `--algorithm-provider` and `--scheduler-name` have been removed from kube-scheduler. Use `ComponentConfig` instead to configure those parameters.
+
 ## {{% heading "whatsnext" %}}
 
 * Read the [kube-scheduler reference](/docs/reference/command-line-tools-reference/kube-scheduler/)
 * Learn about [scheduling](/docs/concepts/scheduling-eviction/kube-scheduler/)
 * Read the [kube-scheduler configuration (v1beta1)](/docs/reference/config-api/kube-scheduler-config.v1beta1/) reference
 * Read the [kube-scheduler configuration (v1beta2)](/docs/reference/config-api/kube-scheduler-config.v1beta2/) reference
-