Add documents about karmada controllers

Signed-off-by: RainbowMango <qdurenhongcai@gmail.com>

docs/README.md

@@ -16,6 +16,7 @@ Refer to [Installing Karmada](./installation/installation.md).
 - [Cluster Failover](./userguide/failover.md)
 - [Aggregated Kubernetes API Endpoint](./userguide/aggregated-api-endpoint.md)
 - [Customizing Resource Interpreter](./userguide/customizing-resource-interpreter.md)
+- [Configuring Controllers](./userguide/configure-controllers.md)
 
 ## Best Practices
 
@@ -23,6 +24,7 @@ Refer to [Installing Karmada](./installation/installation.md).
 
 ## Contributors
 
+- [GitHub workflow](./contributors/guide/github-workflow.md)
 - [Cherry Pick Overview](./contributors/devel/cherry-picks.md)
 
 ## Reference

docs/userguide/configure-controllers.md

@@ -0,0 +1,56 @@
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+**Table of Contents**  *generated with [DocToc](https://github.com/thlorenz/doctoc)*
+
+- [Configure Controllers](#configure-controllers)
+  - [Controllers Overview](#controllers-overview)
+  - [Configure Controllers](#configure-controllers-1)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+
+# Configure Controllers
+
+Karmada maintains a bunch of controllers which are control loops that watch the state of your system, then make or 
+request changes where needed. Each controller tries to move the current state closer to the desired state.
+See [Kubernetes Controller Concepts][1] for more details.
+
+## Controllers Overview
+
+The controllers are embedded into component of `karmada-controller-manager` or `karmada-agent` and will be launched  
+along with components startup. Some controllers may be shared by `karmada-controller-manager` and `karmada-agent`.
+
+| Controller       | In karmada-controller-manager | In karmada-agent |
+|------------------|-------------------------------|-----------------|
+| cluster          | Y                            | N               |
+| clusterStatus    | Y                            | Y               |
+| binding          | Y                            | N               |
+| execution        | Y                            | Y               |
+| workStatus       | Y                            | Y               |
+| namespace        | Y                            | N               |
+| serviceExport    | Y                            | Y               |
+| endpointSlice    | Y                            | N               |
+| serviceImport    | Y                            | N               |
+| unifiedAuth      | Y                            | N               |
+| hpa              | Y                            | N               |
+
+## Configure Controllers
+
+You can use `--controllers` flag to specify the enabled controller list for `karmada-controller-manager` and 
+`karmada-agent`, or disable some of them in addition to the default list.
+
+E.g. Specify a controller list:
+```bash
+--controllers=cluster,clusterStatus,binding,xxx
+```
+
+E.g. Disable some controllers:
+```bash
+--controllers=-hpa,-unifiedAuth
+```
+Use `-foo` to disable the controller named `foo`.
+
+> Note: The default controller list might be changed in the following release. The controllers enabled by last release
+> might be disabled or deprecated and new controllers might be introduced too. Users who are using this flag should 
+> check the release notes before system upgrade.
+
+[1]: https://kubernetes.io/docs/concepts/architecture/controller/