AKS support node image upgrade feature (#1750)

src/aks-preview/HISTORY.md

@@ -2,6 +2,10 @@
 
 Release History
 ===============
+0.4.47
++++++
+* Add "--node-image-only" for "az aks nodepool upgrade" and "az aks upgrade"".
+
 0.4.46
 +++++
 * Fix issues for az aks kollect on private clusters

src/aks-preview/azext_aks_preview/_help.py

@@ -290,6 +290,9 @@
         - name: --control-plane-only
           type: bool
           short-summary: Upgrade the cluster control plane only. If not specified, control plane AND all node pools will be upgraded.
+        - name: --node-image-only
+          type: bool
+          short-summary: Only upgrade node image for agent pools.
 """
 
 helps['aks update'] = """
@@ -535,6 +538,9 @@
         - name: --kubernetes-version -k
           type: string
           short-summary: Version of Kubernetes to upgrade the node pool to, such as "1.11.12".
+        - name: --node-image-only
+          type: bool
+          short-summary: Only upgrade agent pool's node image.
 """
 
 helps['aks nodepool update'] = """

src/aks-preview/azext_aks_preview/custom.py

@@ -71,6 +71,7 @@
 from ._client_factory import get_resource_by_name
 from ._client_factory import cf_container_registry_service
 from ._client_factory import cf_storage
+from ._client_factory import cf_agent_pools
 
 
 from ._helpers import (_populate_api_server_access_profile, _set_vm_set_type,
@@ -1534,12 +1535,34 @@ def aks_upgrade(cmd,    # pylint: disable=unused-argument
                 client,
                 resource_group_name,
                 name,
-                kubernetes_version,
+                kubernetes_version='',
                 control_plane_only=False,
                 no_wait=False,
+                node_image_only=False,
                 **kwargs):  # pylint: disable=unused-argument
+    from knack.prompting import prompt_y_n
     instance = client.get(resource_group_name, name)
 
+    if kubernetes_version != '' and node_image_only:
+        raise CLIError('Conflicting flags. Upgrading the Kubernetes version will also upgrade node image version. If you only want to upgrade the node version please use the "--node-image-only" option only.')
+
+    vmas_cluster = False
+    for agent_profile in instance.agent_pool_profiles:
+        if agent_profile.type.lower() == "availabilityset":
+            vmas_cluster = True
+            break
+
+    if node_image_only:
+        msg = "This node image upgrade operation will run across every node pool in the cluster and might take a while, do you wish to continue?"
+        if not prompt_y_n(msg, default="n"):
+            return None
+        agent_pool_client = cf_agent_pools(cmd.cli_ctx)
+        for agent_pool_profile in instance.agent_pool_profiles:
+            if vmas_cluster:
+                raise CLIError('This cluster is not using VirtualMachineScaleSets. Node image upgrade only operation can only be applied on VirtualMachineScaleSets cluster.')
+            _upgrade_single_agent_pool_node_image(agent_pool_client, resource_group_name, name, agent_pool_profile, no_wait)
+        return None
+
     if instance.kubernetes_version == kubernetes_version:
         if instance.provisioning_state == "Succeeded":
             logger.warning("The cluster is already on version %s and is not in a failed state. No operations "
@@ -1549,17 +1572,9 @@ def aks_upgrade(cmd,    # pylint: disable=unused-argument
             logger.warning("Cluster currently in failed state. Proceeding with upgrade to existing version %s to "
                            "attempt resolution of failed cluster state.", instance.kubernetes_version)
 
-    from knack.prompting import prompt_y_n
-
     upgrade_all = False
     instance.kubernetes_version = kubernetes_version
 
-    vmas_cluster = False
-    for agent_profile in instance.agent_pool_profiles:
-        if agent_profile.type.lower() == "availabilityset":
-            vmas_cluster = True
-            break
-
     # for legacy clusters, we always upgrade node pools with CCP.
     if instance.max_agent_pools < 8 or vmas_cluster:
         if control_plane_only:
@@ -1592,6 +1607,12 @@ def aks_upgrade(cmd,    # pylint: disable=unused-argument
     return sdk_no_wait(no_wait, client.create_or_update, resource_group_name, name, instance)
 
 
+def _upgrade_single_agent_pool_node_image(client, resource_group_name, cluster_name, agent_pool_profile, no_wait):
+    instance = client.get(resource_group_name, cluster_name, agent_pool_profile.name)
+    instance.node_image_version = 'latest'
+    return sdk_no_wait(no_wait, client.create_or_update, resource_group_name, cluster_name, agent_pool_profile.name, instance)
+
+
 def _handle_addons_args(cmd, addons_str, subscription_id, resource_group_name, addon_profiles=None,
                         workspace_resource_id=None, appgw_name=None, appgw_subnet_prefix=None, appgw_id=None, appgw_subnet_id=None, appgw_shared=False, appgw_watch_namespace=None):
     if not addon_profiles:
@@ -2142,11 +2163,23 @@ def aks_agentpool_upgrade(cmd,  # pylint: disable=unused-argument
                           client,
                           resource_group_name,
                           cluster_name,
-                          kubernetes_version,
                           nodepool_name,
-                          no_wait=False):
+                          kubernetes_version='',
+                          no_wait=False,
+                          node_image_only=False):
+
+    from knack.prompting import prompt_y_n
     instance = client.get(resource_group_name, cluster_name, nodepool_name)
+    if kubernetes_version != '' and node_image_only:
+        raise CLIError('Conflicting flags. Upgrading the Kubernetes version will also upgrade node image version. If you only want to upgrade the node version please use the "--node-image-only" option only.')
+
     instance.orchestrator_version = kubernetes_version
+    if node_image_only:
+        msg = "This node image upgrade operation will run across every node in this node pool and might take a while, " \
+              "do you wish to continue? "
+        if not prompt_y_n(msg, default="n"):
+            return None
+        instance.node_image_version = 'latest'
 
     return sdk_no_wait(no_wait, client.create_or_update, resource_group_name, cluster_name, nodepool_name, instance)
 

src/aks-preview/setup.py

@@ -8,7 +8,7 @@
 from codecs import open as open1
 from setuptools import setup, find_packages
 
-VERSION = "0.4.45"
+VERSION = "0.4.47"
 CLASSIFIERS = [
     'Development Status :: 4 - Beta',
     'Intended Audience :: Developers',