[AKS] az aks update: Support VMAS to VMS agent pool migration in AKS commands (#31831)

Author: reneeli123

src/azure-cli/azure/cli/command_modules/acs/_help.py

@@ -1057,6 +1057,9 @@
   - name: --disable-static-egress-gateway
     type: bool
     short-summary: Disable Static Egress Gateway addon to the cluster.
+  - name: --migrate-vmas-to-vms
+    type: bool
+    short-summary: Migrate cluster with VMAS node pool to VMS node pool.
 examples:
   - name: Reconcile the cluster back to its current state.
     text: az aks update -g MyResourceGroup -n MyManagedCluster

src/azure-cli/azure/cli/command_modules/acs/_params.py

@@ -649,6 +649,8 @@ def load_arguments(self, _):
         c.argument('nodepool_labels', nargs='*', validator=validate_nodepool_labels,
                    help='space-separated labels: key[=value] [key[=value] ...]. See https://aka.ms/node-labels for syntax of labels.')
         c.argument('nodepool_taints', validator=validate_nodepool_taints)
+        c.argument('migrate_vmas_to_vms', action='store_true')
+
         # azure monitor profile
         c.argument('enable_azure_monitor_metrics', action='store_true')
         c.argument('azure_monitor_workspace_resource_id', validator=validate_azuremonitorworkspaceresourceid)

src/azure-cli/azure/cli/command_modules/acs/custom.py

@@ -814,6 +814,7 @@ def aks_update(
     max_count=None,
     nodepool_labels=None,
     nodepool_taints=None,
+    migrate_vmas_to_vms=False,
     # azure monitor profile
     enable_azure_monitor_metrics=False,
     azure_monitor_workspace_resource_id=None,

src/azure-cli/azure/cli/command_modules/acs/managed_cluster_decorator.py

@@ -42,6 +42,8 @@
     CONST_DNS_ZONE_CONTRIBUTOR_ROLE,
     CONST_ARTIFACT_SOURCE_CACHE,
     CONST_NONE_UPGRADE_CHANNEL,
+    CONST_AVAILABILITY_SET,
+    CONST_VIRTUAL_MACHINES,
 )
 from azure.cli.command_modules.acs._helpers import (
     check_is_managed_aad_cluster,
@@ -2250,7 +2252,7 @@ def _get_outbound_type(
                     "for more details."
                 )
             if isBasicSKULb:
-                if outbound_type is not None:
+                if not read_from_mc and outbound_type is not None:  # outbound type was default to loadbalancer for BLB creation
                     raise InvalidArgumentValueError(
                         "{outbound_type} doesn't support basic load balancer sku".format(outbound_type=outbound_type)
                     )
@@ -5500,6 +5502,12 @@ def get_disable_static_egress_gateway(self) -> bool:
         # because it's already checked in get_enable_static_egress_gateway
         return self.raw_param.get("disable_static_egress_gateway")
 
+    def get_migrate_vmas_to_vms(self) -> bool:
+        """Obtain the value of migrate_vmas_to_vms.
+        :return: bool
+        """
+        return self.raw_param.get("migrate_vmas_to_vms")
+
 
 class AKSManagedClusterCreateDecorator(BaseAKSManagedClusterDecorator):
     def __init__(
@@ -8781,6 +8789,34 @@ def update_static_egress_gateway(self, mc: ManagedCluster) -> ManagedCluster:
             mc.network_profile.static_egress_gateway_profile.enabled = False
         return mc
 
+    def update_vmas_to_vms(self, mc: ManagedCluster) -> ManagedCluster:
+        """Update the agent pool profile type from VMAS to VMS and LB sku to standard
+        :return: the ManagedCluster object
+        """
+        self._ensure_mc(mc)
+
+        if self.context.get_migrate_vmas_to_vms():
+            msg = (
+                "\nWARNING: This operation will be disruptive to your workload while underway. "
+                "Do you wish to continue?"
+            )
+            if not self.context.get_yes() and not prompt_y_n(msg, default="n"):
+                raise DecoratorEarlyExitException()
+            # Ensure we have valid vmas AP
+            if len(mc.agent_pool_profiles) == 1 and mc.agent_pool_profiles[0].type == CONST_AVAILABILITY_SET:
+                mc.agent_pool_profiles[0].type = CONST_VIRTUAL_MACHINES
+            else:
+                raise ArgumentUsageError('This is not a valid VMAS cluster with {} agent pool profiles and {} agent pool type, we cannot proceed with the migration.'.format(len(mc.agent_pool_profiles), mc.agent_pool_profiles[0].type))
+
+            if mc.network_profile.load_balancer_sku == CONST_LOAD_BALANCER_SKU_BASIC:
+                mc.network_profile.load_balancer_sku = CONST_LOAD_BALANCER_SKU_STANDARD
+
+            # Set agent pool profile count and vm_size to None
+            mc.agent_pool_profiles[0].count = None
+            mc.agent_pool_profiles[0].vm_size = None
+
+        return mc
+
     def update_mc_profile_default(self) -> ManagedCluster:
         """The overall controller used to update the default ManagedCluster profile.
 
@@ -8868,6 +8904,8 @@ def update_mc_profile_default(self) -> ManagedCluster:
         mc = self.update_static_egress_gateway(mc)
         # update kubernetes version and orchestrator version
         mc = self.update_kubernetes_version_and_orchestrator_version(mc)
+        # update VMAS to VMS
+        mc = self.update_vmas_to_vms(mc)
         return mc
 
     def update_kubernetes_version_and_orchestrator_version(self, mc: ManagedCluster) -> ManagedCluster: