8000 [PodLevelResources] Update Downward API defaulting for resource limits by toVersus · Pull Request #132605 · kubernetes/kubernetes · GitHub
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[PodLevelResources] Update Downward API defaulting for resource limits #132605

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[PodLevelResources] Update Downward API defaulting for resource limits #132605

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33 changes: 26 additions & 7 deletions pkg/kubelet/kubelet_resources.go
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Original file line number Diff line number Diff line change
Expand Up @@ -21,18 +21,21 @@ import (

"k8s.io/klog/v2"

"k8s.io/api/core/v1"
corev1 "k8s.io/api/core/v1"
utilfeature "k8s.io/apiserver/pkg/util/feature"
resourcehelper "k8s.io/component-helpers/resource"
"k8s.io/kubernetes/pkg/api/v1/resource"
kubefeatures "k8s.io/kubernetes/pkg/features"
)

// defaultPodLimitsForDownwardAPI copies the input pod, and optional container,
// and applies default resource limits. it returns a copy of the input pod,
// and a copy of the input container (if specified) with default limits
// applied. if a container has no limit specified, it will default the limit to
// the node allocatable.
// TODO: if/when we have pod level resources, we need to update this function
// to use those limits instead of node allocatable.
func (kl *Kubelet) defaultPodLimitsForDownwardAPI(pod *v1.Pod, container *v1.Container) (*v1.Pod, *v1.Container, error) {
// applied.
// If a container has no limits specified, it defaults to the pod-level resources.
// If neither container-level nor pod-level resources are specified, it defaults
// to the node's allocatable resources.
func (kl *Kubelet) defaultPodLimitsForDownwardAPI(pod *corev1.Pod, container *corev1.Container) (*corev1.Pod, *corev1.Container, error) {
if pod == nil {
return nil, nil, fmt.Errorf("invalid input, pod cannot be nil")
}
Expand All @@ -42,13 +45,29 @@ func (kl *Kubelet) defaultPodLimitsForDownwardAPI(pod *v1.Pod, container *v1.Con
return nil, nil, fmt.Errorf("failed to find node object, expected a node")
}
allocatable := node.Status.Allocatable
if utilfeature.DefaultFeatureGate.Enabled(kubefeatures.PodLevelResources) && resourcehelper.IsPodLevelLimitsSet(pod) {
allocatable = allocatable.DeepCopy()
// Resources supported by the Downward API
for _, resource := range []corev1.ResourceName{corev1.ResourceCPU, corev1.ResourceMemory, corev1.ResourceEphemeralStorage} {
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nit - only cpu, memory and huge pages are supported at pod-level.

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Thanks! This slice contains resources supported by the Downward API, so I added a check to verify whether each resource is also supported by Pod Level Resources.

// Skip resources not supported by Pod Level Resources
if !resourcehelper.IsSupportedPodLevelResource(resource) {
continue
}
if val, exists := pod.Spec.Resources.Limits[resource]; exists && !val.IsZero() {
if _, exists := allocatable[resource]; exists {
allocatable[resource] = val.DeepCopy()
}
}
}
}

klog.InfoS("Allocatable", "allocatable", allocatable)
outputPod := pod.DeepCopy()
for idx := range outputPod.Spec.Containers {
resource.MergeContainerResourceLimits(&outputPod.Spec.Containers[idx], allocatable)
}

var outputContainer *v1.Container
var outputContainer *corev1.Container
if container != nil {
outputContainer = container.DeepCopy()
resource.MergeContainerResourceLimits(outputContainer, allocatable)
Expand Down
50 changes: 48 additions & 2 deletions
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Expand Up @@ -25,6 +25,9 @@ import (
apiequality "k8s.io/apimachinery/pkg/api/equality"
"k8s.io/apimachinery/pkg/api/resource"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
utilfeature "k8s.io/apiserver/pkg/util/feature"
featuregatetesting "k8s.io/component-base/featuregate/testing"
kubefeatures "k8s.io/kubernetes/pkg/features"
)

func TestPodResourceLimitsDefaulting(t *testing.T) {
Expand All @@ -46,8 +49,9 @@ func TestPodResourceLimitsDefaulting(t *testing.T) {
},
}
cases := []struct {
pod *v1.Pod
expected *v1.Pod
pod *v1.Pod
expected *v1.Pod
podLevelResourcesEnabled bool
}{
{
pod: getPod("0", "0"),
Expand All @@ -65,9 +69,35 @@ func TestPodResourceLimitsDefaulting(t *testing.T) {
pod: getPod("0", "1Mi"),
expected: getPod("6", "1Mi"),
},
{
pod: getPodWithPodLevelResources("0", "1Mi", "0", "0"),
expected: getPodWithPodLevelResources("0", "1Mi", "6", "1Mi"),
podLevelResourcesEnabled: true,
},
{
pod: getPodWithPodLevelResources("1", "0", "0", "0"),
expected: getPodWithPodLevelResources("1", "0", "1", "4Gi"),
podLevelResourcesEnabled: true,
},
{
pod: getPodWithPodLevelResources("1", "1Mi", "", ""),
expected: getPodWithPodLevelResources("1", "1Mi", "1", "1Mi"),
podLevelResourcesEnabled: true,
},
{
pod: getPodWithPodLevelResources("1", "5Mi", "0", "1Mi"),
expected: getPodWithPodLevelResources("1", "5Mi", "1", "1Mi"),
podLevelResourcesEnabled: true,
},
{
pod: getPodWithPodLevelResources("1", "5Mi", "1", "1Mi"),
expected: getPodWithPodLevelResources("1", "5Mi", "1", "1Mi"),
podLevelResourcesEnabled: true,
},
}
as := assert.New(t)
for idx, tc := range cases {
featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, kubefeatures.PodLevelResources, tc.podLevelResourcesEnabled)
actual, _, err := tk.kubelet.defaultPodLimitsForDownwardAPI(tc.pod, nil)
as.NoError(err, "failed to default pod limits: %v", err)
if !apiequality.Semantic.DeepEqual(tc.expected, actual) {
Expand Down Expand Up @@ -98,3 +128,19 @@ func getPod(cpuLimit, memoryLimit string) *v1.Pod {
},
}
}

func getPodWithPodLevelResources(plCPULimit, plMemoryLimit, clCPULimit, clMemoryLimit string) *v1.Pod {
pod := getPod(clCPULimit, clMemoryLimit)
resources := v1.ResourceRequirements{}
if plCPULimit != "" || plMemoryLimit != "" {
resources.Limits = make(v1.ResourceList)
}
if plCPULimit != "" {
resources.Limits[v1.ResourceCPU] = resource.MustParse(plCPULimit)
}
if plMemoryLimit != "" {
resources.Limits[v1.ResourceMemory] = resource.MustParse(plMemoryLimit)
}
pod.Spec.Resources = &resources
return pod
}
20 changes: 20 additions & 0 deletions staging/src/k8s.io/component-helpers/resource/helpers.go
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Expand Up @@ -114,6 +114,26 @@ func IsPodLevelRequestsSet(pod *v1.Pod) bool {
return false
}

// IsPodLevelLimitsSet checks if pod-level limits are set. It returns true if
// Limits map is non-empty and contains at least one supported pod-level resource.
func IsPodLevelLimitsSet(pod *v1.Pod) bool {
if pod.Spec.Resources == nil {
return false
}

if len(pod.Spec.Resources.Limits) == 0 {
return false
}

for resourceName := range pod.Spec.Resources.Limits {
if IsSupportedPodLevelResource(resourceName) {
return true
}
}

return false
}

// PodRequests computes the total pod requests per the PodResourcesOptions supplied.
// If PodResourcesOptions is nil, then the requests are returned including pod overhead.
// If the PodLevelResources feature is enabled AND the pod-level resources are set,
Expand Down
52 changes: 52 additions & 0 deletions staging/src/k8s.io/component-helpers/resource/helpers_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1554,6 +1554,58 @@ func TestIsPodLevelResourcesSet(t *testing.T) {

}

func TestIsPodLevelLimitsSet(t *testing.T) {
testCases := []struct {
name string
podResources *v1.ResourceRequirements
expected bool
}{
{
name: "nil resources struct",
expected: false,
},
{
name: "empty resources struct",
podResources: &v1.ResourceRequirements{},
expected: false,
},
{
name: "only resource requests set",
podResources: &v1.ResourceRequirements{
Requests: v1.ResourceList{v1.ResourceMemory: resource.MustParse("100Mi")},
},
expected: false,
},
{
name: "only unsupported resource limits set",
podResources: &v1.ResourceRequirements{
Limits: v1.ResourceList{v1.ResourceEphemeralStorage: resource.MustParse("1Mi")},
},
expected: false,
},
{
name: "unsupported and suported resources limits set",
podResources: &v1.ResourceRequirements{
Limits: v1.ResourceList{
v1.ResourceEphemeralStorage: resource.MustParse("1Mi"),
v1.ResourceCPU: resource.MustParse("1m"),
},
},
expected: true,
},
}

for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
testPod := &v1.Pod{Spec: v1.PodSpec{Resources: tc.podResources}}
if got := IsPodLevelLimitsSet(testPod); got != tc.expected {
t.Errorf("got=%t, want=%t", got, tc.expected)
}
})
}

}

func TestPodLevelResourceRequests(t *testing.T) {
restartAlways := v1.ContainerRestartPolicyAlways
testCases := []struct {
Expand Down
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