Kubernetes Fleet - Enable feature flag

Author: shashankbarsin

articles/kubernetes-fleet/quickstart-create-fleet-and-members.md

@@ -37,6 +37,12 @@ Get started with Azure Kubernetes Fleet Manager (Fleet) by using the Azure CLI t
 
 * [Install or upgrade Azure CLI](/cli/azure/install-azure-cli) to version is at least `2.37.0`
 
+* Enable the following feature for each subscription where you'll be creating the fleet resource or where your AKS clusters that will be joined as members are located in:
+
+  ```azurecli
+  az feature register --namespace Microsoft.ContainerService --name FleetResourcePreview
+  ```
+
 * Install the **fleet** Azure CLI extension. Make sure your version is at least `0.1.0`:
 
     ```azurecli