diff --git a/src/aks-preview/HISTORY.rst b/src/aks-preview/HISTORY.rst
index a221dccbf92..00ad96dd87f 100644
--- a/src/aks-preview/HISTORY.rst
+++ b/src/aks-preview/HISTORY.rst
@@ -11,6 +11,12 @@ To release a new version, please select a new version number (usually plus 1 to
 
 Pending
 +++++++
+
+17.0.0b1
++++++++
+* [BREAKING CHANGE]: `az aks create`: Change default value of option `--node-vm-size` to ""
+* [BREAKING CHANGE]: `az aks nodepool add`: Change default value of option `--node-vm-size` to ""
+
 16.0.0b1
 +++++++
 * [BREAKING CHANGE] Remove flux extension from the list of supported core extensions
diff --git a/src/aks-preview/azext_aks_preview/_consts.py b/src/aks-preview/azext_aks_preview/_consts.py
index 53283598270..f0bee2788b7 100644
--- a/src/aks-preview/azext_aks_preview/_consts.py
+++ b/src/aks-preview/azext_aks_preview/_consts.py
@@ -43,8 +43,8 @@
 CONST_VIRTUAL_MACHINES = "VirtualMachines"
 
 # vm size
-CONST_DEFAULT_NODE_VM_SIZE = "Standard_DS2_v2"
-CONST_DEFAULT_WINDOWS_NODE_VM_SIZE = "Standard_D2s_v3"
+CONST_DEFAULT_NODE_VM_SIZE = ""
+CONST_DEFAULT_WINDOWS_NODE_VM_SIZE = ""
 
 # workload runtime
 CONST_WORKLOAD_RUNTIME_OCI_CONTAINER = "OCIContainer"
diff --git a/src/aks-preview/azext_aks_preview/_help.py b/src/aks-preview/azext_aks_preview/_help.py
index be24e489923..c63e17995a6 100644
--- a/src/aks-preview/azext_aks_preview/_help.py
+++ b/src/aks-preview/azext_aks_preview/_help.py
@@ -40,7 +40,7 @@
                          `--service-principal` is specified.
         - name: --node-vm-size -s
           type: string
-          short-summary: Size of Virtual Machines to create as Kubernetes nodes.
+          short-summary: Size of Virtual Machines to create as Kubernetes nodes. If the user does not specify one, server will select a default VM size for her/him.
         - name: --dns-name-prefix -p
           type: string
           short-summary: Prefix for hostnames that are created. If not specified, generate a hostname using the
@@ -1698,7 +1698,7 @@
     parameters:
         - name: --node-vm-size -s
           type: string
-          short-summary: Size of Virtual Machines to create as Kubernetes nodes.
+          short-summary: Size of Virtual Machines to create as Kubernetes nodes. If the user does not specify one, server will select a default VM size for her/him.
         - name: --node-count -c
           type: int
           short-summary: Number of nodes in the Kubernetes agent pool. After creating a cluster, you can change the
diff --git a/src/aks-preview/azext_aks_preview/tests/latest/test_agentpool_decorator.py b/src/aks-preview/azext_aks_preview/tests/latest/test_agentpool_decorator.py
index 42b8ba3ad65..0567d87ddd7 100644
--- a/src/aks-preview/azext_aks_preview/tests/latest/test_agentpool_decorator.py
+++ b/src/aks-preview/azext_aks_preview/tests/latest/test_agentpool_decorator.py
@@ -42,6 +42,7 @@
     InvalidArgumentValueError,
     MutuallyExclusiveArgumentError,
 )
+from deepdiff import DeepDiff
 
 
 class AKSPreviewAgentPoolContextCommonTestCase(unittest.TestCase):
@@ -815,7 +816,7 @@ def common_get_vm_sizes(self):
         )
         agentpool_2 = self.create_initialized_agentpool_instance(os_type="linux")
         ctx_2.attach_agentpool(agentpool_2)
-        self.assertEqual(ctx_2.get_vm_sizes(), [CONST_DEFAULT_NODE_VM_SIZE])
+        self.assertEqual(ctx_2.get_vm_sizes(), [CONST_DEFAULT_NODE_VM_SIZE], DeepDiff(ctx_2.get_vm_sizes(), [CONST_DEFAULT_NODE_VM_SIZE]))
 
         # custom
         ctx_3 = AKSPreviewAgentPoolContext(
diff --git a/src/aks-preview/azext_aks_preview/tests/latest/test_aks_commands.py b/src/aks-preview/azext_aks_preview/tests/latest/test_aks_commands.py
index eccb42b903d..9d4474b02bf 100644
--- a/src/aks-preview/azext_aks_preview/tests/latest/test_aks_commands.py
+++ b/src/aks-preview/azext_aks_preview/tests/latest/test_aks_commands.py
@@ -8023,7 +8023,6 @@ def test_aks_nodepool_update_taints_msi(
                 self.check("resourceGroup", "{resource_group}"),
                 self.check("agentPoolProfiles[0].count", 1),
                 self.check("agentPoolProfiles[0].osType", "Linux"),
-                self.check("agentPoolProfiles[0].vmSize", "Standard_DS2_v2"),
                 self.check("agentPoolProfiles[0].mode", "System"),
                 self.check("dnsPrefix", "{dns_name_prefix}"),
                 self.exists("kubernetesVersion"),
@@ -8132,7 +8131,6 @@ def test_aks_nodepool_update_label_msi(
                 self.check("resourceGroup", "{resource_group}"),
                 self.check("agentPoolProfiles[0].count", 1),
                 self.check("agentPoolProfiles[0].osType", "Linux"),
-                self.check("agentPoolProfiles[0].vmSize", "Standard_DS2_v2"),
                 self.check("agentPoolProfiles[0].mode", "System"),
                 self.check("dnsPrefix", "{dns_name_prefix}"),
                 self.exists("kubernetesVersion"),
diff --git a/src/aks-preview/setup.py b/src/aks-preview/setup.py
index e29e79a08ee..aac89ad5596 100644
--- a/src/aks-preview/setup.py
+++ b/src/aks-preview/setup.py
@@ -9,7 +9,7 @@
 
 from setuptools import setup, find_packages
 
-VERSION = "16.0.0b1"
+VERSION = "17.0.0b1"
 
 CLASSIFIERS = [
     "Development Status :: 4 - Beta",