fix: skip runtimeClassName injection when gpuPodRuntimeClassName is e… (#1131)

Signed-off-by: Yuan Chen <yuanchen97@gmail.com>
Co-authored-by: Yuan Chen <yuanchen97@gmail.com>

Author: enoodle

CHANGELOG.md

@@ -4,11 +4,12 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
-## [Unreleased]
+## [v0.9.13] - 2026-03-04
 
 ### Fixed
 - Fixed a bug where queue status did not reflect its podgroups resources correctly [#1049](https://github.com/NVIDIA/KAI-Scheduler/pull/1049)
 - Fixed plugin server (snapshot and job-order endpoints) listening on all interfaces by binding to localhost only.
+- Fixed admission webhook to skip runtimeClassName injection when gpuPodRuntimeClassName is empty [#1035](https://github.com/NVIDIA/KAI-Scheduler/pull/1035)
 
 ## [v0.9.12] - 2026-01-21
 

pkg/admission/webhook/v1alpha2/runtimeenforcement/runtime_enforcement.go

@@ -30,6 +30,11 @@ func (p *RuntimeEnforcement) Validate(pod *v1.Pod) error {
 }
 
 func (p *RuntimeEnforcement) Mutate(pod *v1.Pod) error {
+	// Skip runtimeClassName injection entirely when configured with empty string
+	if p.gpuPodRuntimeClassName == "" {
+		return nil
+	}
+
 	// in order to no collide with custom reservation pods runtimeClass
 	if resourcereservation.IsGPUReservationPod(pod) {
 		return nil

pkg/admission/webhook/v1alpha2/runtimeenforcement/runtime_enforcement_test.go

@@ -81,6 +81,33 @@ func TestMutate(t *testing.T) {
 			},
 			expectedError: nil,
 		},
+		{
+			name:                   "empty gpuPodRuntimeClassName skips runtimeClass injection",
+			gpuPodRuntimeClassName: "",
+			incomingPod: &v1.Pod{
+				Spec: v1.PodSpec{
+					Containers: []v1.Container{
+						{
+							Resources: v1.ResourceRequirements{
+								Limits: v1.ResourceList{constants.GpuResource: resource.MustParse("1")},
+							},
+						},
+					},
+				},
+			},
+			expectedOutboundPod: &v1.Pod{
+				Spec: v1.PodSpec{
+					Containers: []v1.Container{
+						{
+							Resources: v1.ResourceRequirements{
+								Limits: v1.ResourceList{constants.GpuResource: resource.MustParse("1")},
+							},
+						},
+					},
+				},
+			},
+			expectedError: nil,
+		},
 		{
 			name:                   "pod with GPU request and runtimeClassName set",
 			gpuPodRuntimeClassName: constants.DefaultRuntimeClassName,