[AKS] update control-plane-only user confirmation prompt (#9404)

Author: m-chau

src/aks-preview/HISTORY.rst

@@ -11,7 +11,11 @@ To release a new version, please select a new version number (usually plus 1 to
 
 Pending
 +++++++
+
+19.0.0b17
++++++++
 * `az aks bastion`: Correctly configure `$KUBECONFIG` values for tunneling traffic into a private AKS cluster.
+* Update user prompt for `az aks upgrade` command to clarify the implication of the `--control-plane-only` options.
 
 19.0.0b16
 +++++++

src/aks-preview/azext_aks_preview/custom.py

@@ -1708,8 +1708,10 @@ def aks_upgrade(cmd,
             upgrade_all = True
         else:
             msg = (
-                "Since control-plane-only argument is specified, this will upgrade only the control plane to "
-                f"{instance.kubernetes_version}. Node pool will not change. Continue?"
+                "Since --control-plane-only parameter is specified, this will upgrade only the kubernetes version of the control plane to  "
+                f"{instance.kubernetes_version}. Kubernetes versions of the node pools will remain unchanged, "
+                "but node image version may be upgraded if there has been cluster config change that requires VM reimage. "
+                "Continue?"
             )
             if not yes and not prompt_y_n(msg, default="n"):
                 return None

src/aks-preview/setup.py

@@ -9,7 +9,7 @@
 
 from setuptools import find_packages, setup
 
-VERSION = "19.0.0b16"
+VERSION = "19.0.0b17"
 
 CLASSIFIERS = [
     "Development Status :: 4 - Beta",