From 2d8939c4aef8f060d413bb27272ba38cd7171fbe Mon Sep 17 00:00:00 2001
From: Sotiris Salloumis <sotiris.salloumis@est.tech>
Date: Tue, 22 Oct 2024 19:25:39 +0200
Subject: [PATCH] Gate: disallow in-place resize for guaranteed pods on nodes
 with a static topology policy

New gate "InPlacePodVerticalScalingExclusiveCPUs" is off by default,
but can be enabled to unblock development of Static CPU management alongside
InPlacePodVerticalScaling.
---
 pkg/features/kube_features.go                     |  8 ++++++++
 pkg/features/versioned_kube_features.go           |  4 ++++
 pkg/kubelet/kubelet.go                            | 15 +++++++++++++++
 .../test_data/versioned_feature_list.yaml         |  6 ++++++
 4 files changed, 33 insertions(+)

diff --git a/pkg/features/kube_features.go b/pkg/features/kube_features.go
index 4fbfdee171c..d95fa0b6e6f 100644
--- a/pkg/features/kube_features.go
+++ b/pkg/features/kube_features.go
@@ -270,6 +270,14 @@ const (
 	// InPlacePodVerticalScaling also be enabled.
 	InPlacePodVerticalScalingAllocatedStatus featuregate.Feature = "InPlacePodVerticalScalingAllocatedStatus"
 
+	// owner: @tallclair @esotsal
+	// alpha: v1.32
+	//
+	// Allow resource resize for containers in Guaranteed pods with integer CPU requests ( default false ).
+	// Applies only in nodes with InPlacePodVerticalScaling and CPU Manager features enabled, and
+	// CPU Manager Static Policy option set.
+	InPlacePodVerticalScalingExclusiveCPUs featuregate.Feature = "InPlacePodVerticalScalingExclusiveCPUs"
+
 	// owner: @trierra
 	//
 	// Disables the Portworx in-tree driver.
diff --git a/pkg/features/versioned_kube_features.go b/pkg/features/versioned_kube_features.go
index 2211528cac0..ffebcbe75c8 100644
--- a/pkg/features/versioned_kube_features.go
+++ b/pkg/features/versioned_kube_features.go
@@ -397,6 +397,10 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 		{Version: version.MustParse("1.32"), Default: false, PreRelease: featuregate.Alpha},
 	},
 
+	InPlacePodVerticalScalingExclusiveCPUs: {
+		{Version: version.MustParse("1.32"), Default: false, PreRelease: featuregate.Alpha},
+	},
+
 	InTreePluginPortworxUnregister: {
 		{Version: version.MustParse("1.23"), Default: false, PreRelease: featuregate.Alpha},
 	},
diff --git a/pkg/kubelet/kubelet.go b/pkg/kubelet/kubelet.go
index 94f2a9ded95..d4416fce401 100644
--- a/pkg/kubelet/kubelet.go
+++ b/pkg/kubelet/kubelet.go
@@ -2838,6 +2838,21 @@ func isPodResizeInProgress(pod *v1.Pod, podStatus *kubecontainer.PodStatus) bool
 // pod should hold the desired (pre-allocated) spec.
 // Returns true if the resize can proceed.
 func (kl *Kubelet) canResizePod(pod *v1.Pod) (bool, v1.PodResizeStatus) {
+	if v1qos.GetPodQOS(pod) == v1.PodQOSGuaranteed && !utilfeature.DefaultFeatureGate.Enabled(features.InPlacePodVerticalScalingExclusiveCPUs) {
+		if utilfeature.DefaultFeatureGate.Enabled(features.CPUManager) {
+			if kl.containerManager.GetNodeConfig().CPUManagerPolicy == "static" {
+				klog.V(3).InfoS("Resize is infeasible for Guaranteed Pods alongside CPU Manager static policy")
+				return false, v1.PodResizeStatusInfeasible
+			}
+		}
+		if utilfeature.DefaultFeatureGate.Enabled(features.MemoryManager) {
+			if kl.containerManager.GetNodeConfig().ExperimentalMemoryManagerPolicy == "static" {
+				klog.V(3).InfoS("Resize is infeasible for Guaranteed Pods alongside Memory Manager static policy")
+				return false, v1.PodResizeStatusInfeasible
+			}
+		}
+	}
+
 	node, err := kl.getNodeAnyWay()
 	if err != nil {
 		klog.ErrorS(err, "getNodeAnyway function failed")
diff --git a/test/featuregates_linter/test_data/versioned_feature_list.yaml b/test/featuregates_linter/test_data/versioned_feature_list.yaml
index f640e4b2280..6451f5e259c 100644
--- a/test/featuregates_linter/test_data/versioned_feature_list.yaml
+++ b/test/featuregates_linter/test_data/versioned_feature_list.yaml
@@ -522,6 +522,12 @@
     lockToDefault: false
     preRelease: Alpha
     version: "1.32"
+- name: InPlacePodVerticalScalingExclusiveCPUs
+  versionedSpecs:
+  - default: false
+    lockToDefault: false
+    preRelease: Alpha
+    version: "1.32"
 - name: InTreePluginPortworxUnregister
   versionedSpecs:
   - default: false