diff --git a/providers/openstack/scs2/cluster-class/templates/cluster-class.yaml b/providers/openstack/scs2/cluster-class/templates/cluster-class.yaml
index 34f30d6f..d7fbd338 100644
--- a/providers/openstack/scs2/cluster-class/templates/cluster-class.yaml
+++ b/providers/openstack/scs2/cluster-class/templates/cluster-class.yaml
@@ -117,7 +117,7 @@ spec:
         openAPIV3Schema:
           type: string
           default: "SCS-2V-4"
-          example: "SCS-2V-4"
+          example: "SCS-2V-4-20s"
           description: |-
             OpenStack instance flavor for control plane nodes.
             (Default: SCS-2V-4, replace by SCS-2V-4-20s or specify a controlPlaneRootDisk.)
@@ -126,13 +126,13 @@ spec:
       schema:
         openAPIV3Schema:
           type: integer
-          minimum: 1
+          minimum: 0
           example: 25
           default: 50
           description: |-
             Root disk size in GiB for control-plane nodes.
             OpenStack volume will be created and used instead of an ephemeral disk defined in flavor.
-            Should only be used for the diskless flavors.
+            Should only be used for the diskless flavors (>= 20), otherwise set to 0.
     - name: controlPlaneServerGroupID
       required: false
       schema:
@@ -173,13 +173,13 @@ spec:
       schema:
         openAPIV3Schema:
           type: integer
-          minimum: 1
+          minimum: 0
           example: 25
           default: 50
           description: |-
             Root disk size in GiB for worker nodes.
             OpenStack volume will be created and used instead of an ephemeral disk defined in flavor.
-            Should be used for the diskless flavors.
+            Should be used for the diskless flavors (>= 20), otherwise set to 0.
     - name: workerServerGroupID
       required: false
       schema:
diff --git a/providers/openstack/scs2/csctl.yaml b/providers/openstack/scs2/csctl.yaml
index d6f827bd..e81facfe 100644
--- a/providers/openstack/scs2/csctl.yaml
+++ b/providers/openstack/scs2/csctl.yaml
@@ -1,7 +1,7 @@
 apiVersion: csctl.clusterstack.x-k8s.io/v1alpha1
 config:
   clusterStackName: scs2
-  kubernetesVersion: v1.33.4
+  kubernetesVersion: v1.33.5
   provider:
     apiVersion: openstack.csctl.clusterstack.x-k8s.io/v1alpha1
     type: openstack
diff --git a/providers/openstack/scs2/versions.yaml b/providers/openstack/scs2/versions.yaml
index f21958d4..3e1e0dad 100644
--- a/providers/openstack/scs2/versions.yaml
+++ b/providers/openstack/scs2/versions.yaml
@@ -4,6 +4,6 @@
 - kubernetes: 1.32.8
   cinder_csi: 2.32.2
   occm: 2.32.0
-- kubernetes: 1.33.4
+- kubernetes: 1.33.5
   cinder_csi: 2.33.1
   occm: 2.33.1