fix(acns): npe issue for acns transit encryption flag

Signed-off-by: Quang Nguyen <nguyenquang@microsoft.com>

Author: nddq

src/aks-preview/HISTORY.rst

@@ -14,6 +14,10 @@ Pending
 * Add `--node-provisioning-default-pools` to the `az aks update` command.
 * Add `--node-provisioning-default-pools` to the `az aks create` command.
 
+18.0.0b14
++++++++
+* Fixed NPE issue for `--acns-transit-encryption-type`.
+
 18.0.0b13
 +++++++
 * Add option `--enable-http-proxy` to `az aks update`.

src/aks-preview/azext_aks_preview/managed_cluster_decorator.py

@@ -3027,13 +3027,10 @@ def set_up_network_profile(self, mc: ManagedCluster) -> ManagedCluster:
                     acns.security.advanced_network_policies = acns_advanced_networkpolicies
             if acns_transit_encryption_type is not None:
                 if acns.security is None:
-                    acns.security = self.models.AdvancedNetworkingSecurity(
-                        transit_encryption=self.models.AdvancedNetworkingSecurityTransitEncryption(
-                            type=acns_transit_encryption_type
-                        )
-                    )
-                else:
-                    acns.security.transit_encryption.type = acns_transit_encryption_type
+                    acns.security = self.models.AdvancedNetworkingSecurity()
+                if acns.security.transit_encryption is None:
+                    acns.security.transit_encryption = self.models.AdvancedNetworkingSecurityTransitEncryption()
+                acns.security.transit_encryption.type = acns_transit_encryption_type
             network_profile.advanced_networking = acns
         return mc
 
@@ -4142,13 +4139,10 @@ def update_acns_in_network_profile(self, mc: ManagedCluster) -> ManagedCluster:
                     acns.security.advanced_network_policies = acns_advanced_networkpolicies
             if acns_transit_encryption_type is not None:
                 if acns.security is None:
-                    acns.security = self.models.AdvancedNetworkingSecurity(
-                        transit_encryption=self.models.AdvancedNetworkingSecurityTransitEncryption(
-                            type=acns_transit_encryption_type
-                        )
-                    )
-                else:
-                    acns.security.transit_encryption.type = acns_transit_encryption_type
+                    acns.security = self.models.AdvancedNetworkingSecurity()
+                if acns.security.transit_encryption is None:
+                    acns.security.transit_encryption = self.models.AdvancedNetworkingSecurityTransitEncryption()
+                acns.security.transit_encryption.type = acns_transit_encryption_type
             mc.network_profile.advanced_networking = acns
         return mc