docs: Cluster Autoscaler is deployed on the management cluster (#608)

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Fixes #

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Author: dkoshkin

docs/content/addons/cluster-autoscaler.md

@@ -3,8 +3,15 @@ title = "Cluster Autoscaler"
 icon = "fa-solid fa-up-right-and-down-left-from-center"
 +++
 
-By leveraging CAPI cluster lifecycle hooks, this handler deploys [Cluster Autoscaler] on the new cluster at the
-`AfterControlPlaneInitialized` phase.
+By leveraging CAPI cluster lifecycle hooks, this handler deploys [Cluster Autoscaler] on the management cluster
+for every Cluster at the `AfterControlPlaneInitialized` phase.Unlike other addons, the Cluster Autoscaler
+is deployed on the management cluster because it also interacts with the CAPI resources to scale the number of Machines.
+The Cluster Autoscaler Pod will not start on the management cluster until the CAPI resources are [pivoted][Pivot]
+to that management cluster.
+
+> Note the Cluster Autoscale controller needs to be running for any scaling operations to occur,
+> just updating the min and max size annotations in the Cluster object will not be enough.
+> You can however manually change the number of replicas by modifying the MachineDeployment object directly.
 
 Deployment of Cluster Autoscaler is opt-in via the  [provider-specific cluster configuration]({{< ref ".." >}}).
 
@@ -38,10 +45,11 @@ spec:
               cluster.x-k8s.io/cluster-api-autoscaler-node-group-max-size: "3"
               cluster.x-k8s.io/cluster-api-autoscaler-node-group-min-size: "1"
           name: md-0
-          # Remove the replicas field, otherwise the topology controller will revert back the autoscaler's changes
+          # Do not set the replicas field, otherwise the topology controller will revert back the autoscaler's changes
 ```
 
 To deploy the addon via `ClusterResourceSet` replace the value of `strategy` with `ClusterResourceSet`.
 
 [Cluster Autoscaler]: https://github.com/kubernetes/autoscaler/tree/master/cluster-autoscaler/cloudprovider/clusterapi
 [Cluster API Add-on Provider for Helm]: https://github.com/kubernetes-sigs/cluster-api-addon-provider-helm
+[Pivot]: https://main.cluster-api.sigs.k8s.io/clusterctl/commands/move#pivot