integ/kubernetes/kubernetes-1.24.4/debian/deb_folder/patches/kubelet-cpumanager-infra-pods-use-system-reserved-CP.patch

From 70399c6eebe5216332e77b0f56ace7028168c726 Mon Sep 17 00:00:00 2001
From: Gleb Aronsky <gleb.aronsky@windriver.com>
Date: Mon, 21 Mar 2022 17:25:07 -0300
Subject: [PATCH] kubelet cpumanager infra pods use system reserved CPUs

This assigns system infrastructure pods to the "reserved" cpuset
to isolate them from the shared pool of CPUs.

Infrastructure pods include any pods that belong to the kube-system,
armada, cert-manager, vault, platform-deployment-manager, portieris,
notification, flux-helm or metrics-server namespaces.

The implementation is a bit simplistic, it is assumed that the
"reserved" cpuset is large enough to handle all infrastructure pods
CPU allocations.

This also prevents infrastucture pods from using Guaranteed resources.

Co-authored-by: Jim Gauld <james.gauld@windriver.com>
Signed-off-by: Gleb Aronsky <gleb.aronsky@windriver.com>
Signed-off-by: Thiago Miranda <ThiagoOliveira.Miranda@windriver.com>
Signed-off-by: Kaustubh Dhokte <kaustubh.dhokte@windriver.com>
---
 pkg/kubelet/cm/cpumanager/policy_static.go    | 47 +++++++++++++++++--
 .../cm/cpumanager/policy_static_test.go       | 19 +++++++-
 2 files changed, 61 insertions(+), 5 deletions(-)

diff --git a/pkg/kubelet/cm/cpumanager/policy_static.go b/pkg/kubelet/cm/cpumanager/policy_static.go
index 09e0fc0ea0e..a3c93a896df 100644
--- a/pkg/kubelet/cm/cpumanager/policy_static.go
+++ b/pkg/kubelet/cm/cpumanager/policy_static.go
@@ -53,6 +53,11 @@ func (e SMTAlignmentError) Type() string {
 	return ErrorSMTAlignment
 }
 
+// Define namespaces used by platform infrastructure pods
+var infraNamespaces = [...]string{
+	"kube-system", "armada", "cert-manager", "platform-deployment-manager", "portieris", "vault", "notification", "flux-helm", "metrics-server",
+}
+
 // staticPolicy is a CPU manager policy that does not change CPU
 // assignments for exclusively pinned guaranteed containers after the main
 // container process starts.
@@ -121,10 +126,11 @@ func NewStaticPolicy(topology *topology.CPUTopology, numReservedCPUs int, reserv
 	klog.InfoS("Static policy created with configuration", "options", opts)
 
 	policy := &staticPolicy{
-		topology:    topology,
-		affinity:    affinity,
-		cpusToReuse: make(map[string]cpuset.CPUSet),
-		options:     opts,
+		topology:        topology,
+		affinity:        affinity,
+		excludeReserved: excludeReserved,
+		cpusToReuse:     make(map[string]cpuset.CPUSet),
+		options:         opts,
 	}
 
 	allCPUs := topology.CPUDetails.CPUs()
@@ -263,6 +269,25 @@ func (p *staticPolicy) updateCPUsToReuse(pod *v1.Pod, container *v1.Container, c
 }
 
 func (p *staticPolicy) Allocate(s state.State, pod *v1.Pod, container *v1.Container) error {
+	// Process infra pods before guaranteed pods
+	if isKubeInfra(pod) {
+		// Container belongs in reserved pool.
+		// We don't want to fall through to the p.guaranteedCPUs() clause below so return either nil or error.
+		if _, ok := s.GetCPUSet(string(pod.UID), container.Name); ok {
+			klog.Infof("[cpumanager] static policy: reserved container already present in state, skipping (namespace: %s, pod UID: %s, pod: %s, container: %s)", pod.Namespace, string(pod.UID), pod.Name, container.Name)
+			return nil
+		}
+
+		cpuset := p.reserved
+		if cpuset.IsEmpty() {
+			// If this happens then someone messed up.
+			return fmt.Errorf("[cpumanager] static policy: reserved container unable to allocate cpus (namespace: %s, pod UID: %s, pod: %s, container: %s); cpuset=%v, reserved:%v", pod.Namespace, string(pod.UID), pod.Name, container.Name, cpuset, p.reserved)
+		}
+		s.SetCPUSet(string(pod.UID), container.Name, cpuset)
+		klog.Infof("[cpumanager] static policy: reserved: AddContainer (namespace: %s, pod UID: %s, pod: %s, container: %s); cpuset=%v", pod.Namespace, string(pod.UID), pod.Name, container.Name, cpuset)
+		return nil
+	}
+
 	if numCPUs := p.guaranteedCPUs(pod, container); numCPUs != 0 {
 		klog.InfoS("Static policy: Allocate", "pod", klog.KObj(pod), "containerName", container.Name)
 		// container belongs in an exclusively allocated pool
@@ -382,6 +407,10 @@ func (p *staticPolicy) guaranteedCPUs(pod *v1.Pod, container *v1.Container) int
 	if cpuQuantity.Value()*1000 != cpuQuantity.MilliValue() {
 		return 0
 	}
+	// Infrastructure pods use reserved CPUs even if they're in the Guaranteed QoS class
+	if isKubeInfra(pod) {
+		return 0
+	}
 	// Safe downcast to do for all systems with < 2.1 billion CPUs.
 	// Per the language spec, `int` is guaranteed to be at least 32 bits wide.
 	// https://golang.org/ref/spec#Numeric_types
@@ -595,3 +624,13 @@ func (p *staticPolicy) generateCPUTopologyHints(availableCPUs cpuset.CPUSet, reu
 
 	return hints
 }
+
+// check if a given pod is in a platform infrastructure namespace
+func isKubeInfra(pod *v1.Pod) bool {
+	for _, namespace := range infraNamespaces {
+		if namespace == pod.Namespace {
+			return true
+		}
+	}
+	return false
+}
diff --git a/pkg/kubelet/cm/cpumanager/policy_static_test.go b/pkg/kubelet/cm/cpumanager/policy_static_test.go
index 81251e576fd..d4b4b790210 100644
--- a/pkg/kubelet/cm/cpumanager/policy_static_test.go
+++ b/pkg/kubelet/cm/cpumanager/policy_static_test.go
@@ -886,7 +886,8 @@ func TestStaticPolicyStartWithResvList(t *testing.T) {
 }
 
 func TestStaticPolicyAddWithResvList(t *testing.T) {
-
+	infraPod := makePod("fakePod", "fakeContainer2", "200m", "200m")
+	infraPod.Namespace = "kube-system"
 	testCases := []staticPolicyTestWithResvList{
 		{
 			description:     "GuPodSingleCore, SingleSocketHT, ExpectError",
@@ -928,6 +929,22 @@ func TestStaticPolicyAddWithResvList(t *testing.T) {
 			expCPUAlloc:     true,
 			expCSet:         cpuset.NewCPUSet(4, 5),
 		},
+		{
+			description:     "InfraPod, SingleSocketHT, ExpectAllocReserved",
+			topo:            topoSingleSocketHT,
+			numReservedCPUs: 2,
+			reserved:        cpuset.NewCPUSet(0, 1),
+			stAssignments: state.ContainerCPUAssignments{
+				"fakePod": map[string]cpuset.CPUSet{
+					"fakeContainer100": cpuset.NewCPUSet(2, 3, 6, 7),
+				},
+			},
+			stDefaultCPUSet: cpuset.NewCPUSet(4, 5),
+			pod:             infraPod,
+			expErr:          nil,
+			expCPUAlloc:     true,
+			expCSet:         cpuset.NewCPUSet(0, 1),
+		},
 	}
 
 	testExcl := true
-- 
2.25.1