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fix: use only evictionHard for allocatable capacity calculation #8565

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Merged
jigisha620 merged 4 commits into from
Jan 13, 2026
Merged

fix: use only evictionHard for allocatable capacity calculation #8565

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ed3329c
fix: use only evictionHard for allocatable capacity calculation
moko-poi Oct 5, 2025
e07f400
style: remove redundant comment in evictionThreshold function
moko-poi Oct 5, 2025
538ac5f
fix: remove unused parameters from evictionThreshold function
moko-poi Oct 11, 2025
07e8b64
test: update eviction threshold tests to reflect evictionSoft being i…
moko-poi Nov 4, 2025
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31 changes: 16 additions & 15 deletions pkg/providers/instancetype/suite_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1322,11 +1322,11 @@ var _ = Describe("InstanceTypeProvider", func() {
nodeClass.AMIFamily(),
nil,
)
Expect(it.Overhead.EvictionThreshold.Memory().String()).To(Equal("50Mi"))
Expect(it.Overhead.EvictionThreshold.Memory().String()).To(Equal("100Mi"))
})
})
Context("Eviction Soft", func() {
It("should override eviction threshold when specified as a quantity", func() {
It("should use default threshold when only evictionSoft is specified", func() {
nodeClass.Spec.Kubelet = &v1.KubeletConfiguration{
SystemReserved: map[string]string{
string(corev1.ResourceMemory): "20Gi",
Expand Down Expand Up @@ -1354,9 +1354,9 @@ var _ = Describe("InstanceTypeProvider", func() {
nodeClass.AMIFamily(),
nil,
)
Expect(it.Overhead.EvictionThreshold.Memory().String()).To(Equal("500Mi"))
Expect(it.Overhead.EvictionThreshold.Memory().String()).To(Equal("100Mi"))
})
It("should override eviction threshold when specified as a percentage value", func() {
It("should use evictionHard percentage and ignore evictionSoft percentage", func() {
nodeClass.Spec.Kubelet = &v1.KubeletConfiguration{
SystemReserved: map[string]string{
string(corev1.ResourceMemory): "20Gi",
Expand Down Expand Up @@ -1387,9 +1387,9 @@ var _ = Describe("InstanceTypeProvider", func() {
nodeClass.AMIFamily(),
nil,
)
Expect(it.Overhead.EvictionThreshold.Memory().Value()).To(BeNumerically("~", float64(it.Capacity.Memory().Value())*0.1, 10))
Expect(it.Overhead.EvictionThreshold.Memory().Value()).To(BeNumerically("~", float64(it.Capacity.Memory().Value())*0.05, 10))
})
It("should consider the eviction threshold disabled when specified as 100%", func() {
It("should use default threshold when evictionSoft is 100% (ignored)", func() {
nodeClass.Spec.Kubelet = &v1.KubeletConfiguration{
SystemReserved: map[string]string{
string(corev1.ResourceMemory): "20Gi",
Expand Down Expand Up @@ -1417,7 +1417,7 @@ var _ = Describe("InstanceTypeProvider", func() {
nodeClass.AMIFamily(),
nil,
)
Expect(it.Overhead.EvictionThreshold.Memory().String()).To(Equal("0"))
Expect(it.Overhead.EvictionThreshold.Memory().String()).To(Equal("100Mi"))
})
It("should ignore eviction threshold when using Bottlerocket AMI", func() {
nodeClass.Spec.AMISelectorTerms = []v1.AMISelectorTerm{{Alias: "bottlerocket@latest"}}
Expand Down Expand Up @@ -1476,7 +1476,7 @@ var _ = Describe("InstanceTypeProvider", func() {
Expect(it.Overhead.EvictionThreshold.Memory().String()).To(Equal("100Mi"))
Expect(it.Overhead.EvictionThreshold.StorageEphemeral().AsApproximateFloat64()).To(BeNumerically("~", resources.Quantity("2Gi").AsApproximateFloat64()))
})
It("should take the greater of evictionHard and evictionSoft for overhead as a value", func() {
It("should use only evictionHard for overhead, ignoring evictionSoft", func() {
nodeClass.Spec.Kubelet = &v1.KubeletConfiguration{
SystemReserved: map[string]string{
string(corev1.ResourceMemory): "20Gi",
Expand Down Expand Up @@ -1507,9 +1507,10 @@ var _ = Describe("InstanceTypeProvider", func() {
nodeClass.AMIFamily(),
nil,
)
Expect(it.Overhead.EvictionThreshold.Memory().String()).To(Equal("3Gi"))
// Should use evictionHard (1Gi), not evictionSoft (3Gi)
Expect(it.Overhead.EvictionThreshold.Memory().String()).To(Equal("1Gi"))
})
It("should take the greater of evictionHard and evictionSoft for overhead as a value", func() {
It("should use only evictionHard percentage for overhead, ignoring evictionSoft", func() {
nodeClass.Spec.Kubelet = &v1.KubeletConfiguration{
SystemReserved: map[string]string{
string(corev1.ResourceMemory): "20Gi",
Expand Down Expand Up @@ -1540,9 +1541,10 @@ var _ = Describe("InstanceTypeProvider", func() {
nodeClass.AMIFamily(),
nil,
)
// Should use evictionHard (5%), not evictionSoft (2%)
Expect(it.Overhead.EvictionThreshold.Memory().Value()).To(BeNumerically("~", float64(it.Capacity.Memory().Value())*0.05, 10))
})
It("should take the greater of evictionHard and evictionSoft for overhead with mixed percentage/value", func() {
It("should use only evictionHard value with mixed percentage/value types", func() {
nodeClass.Spec.Kubelet = &v1.KubeletConfiguration{
SystemReserved: map[string]string{
string(corev1.ResourceMemory): "20Gi",
Expand Down Expand Up @@ -1573,7 +1575,8 @@ var _ = Describe("InstanceTypeProvider", func() {
nodeClass.AMIFamily(),
nil,
)
Expect(it.Overhead.EvictionThreshold.Memory().Value()).To(BeNumerically("~", float64(it.Capacity.Memory().Value())*0.1, 10))
// Should use evictionHard (1Gi), not evictionSoft (10%)
Expect(it.Overhead.EvictionThreshold.Memory().String()).To(Equal("1Gi"))
})
})
It("should default max pods based off of network interfaces", func() {
Expand Down Expand Up @@ -2596,7 +2599,6 @@ var _ = Describe("InstanceTypeProvider", func() {
// kubelet.kubeReserved
// kubelet.systemReserved
// kubelet.evictionHard
// kubelet.evictionSoft
// kubelet.maxPods
nodeClass.Spec.Kubelet = &v1.KubeletConfiguration{
KubeReserved: map[string]string{string(corev1.ResourceCPU): "1"},
Expand All @@ -2612,7 +2614,6 @@ var _ = Describe("InstanceTypeProvider", func() {
{KubeReserved: map[string]string{string(corev1.ResourceCPU): "20"}},
{SystemReserved: map[string]string{string(corev1.ResourceMemory): "10Gi"}},
{EvictionHard: map[string]string{"memory.available": "52%"}},
{EvictionSoft: map[string]string{"nodefs.available": "132%"}},
{MaxPods: aws.Int32(20)},
}
ExpectApplied(ctx, env.Client, nodeClass)
Expand All @@ -2634,7 +2635,7 @@ var _ = Describe("InstanceTypeProvider", func() {
instanceTypeResults = append(instanceTypeResults, instancetypes)
}

// Based on the nodeclass configuration, we expect to have 5 unique set of instance types
// Based on the nodeclass configuration, we expect to have 4 unique set of instance types
ExpectUniqueInstanceTypeLists(instanceTypeResults...)
})
It("changes to nodeclass fields should result in a different set of instances types", func() {
Expand Down
25 changes: 9 additions & 16 deletions pkg/providers/instancetype/types.go
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Original file line number Diff line number Diff line change
Expand Up @@ -145,7 +145,7 @@ func NewInstanceType(
Overhead: &cloudprovider.InstanceTypeOverhead{
KubeReserved: kubeReservedResources(cpu(info), lo.Ternary(amiFamily.FeatureFlags().UsesENILimitedMemoryOverhead, ENILimitedPods(ctx, info, 0), pods(ctx, info, amiFamily, maxPods, podsPerCore)), kubeReserved),
SystemReserved: systemReservedResources(systemReserved),
EvictionThreshold: evictionThreshold(memory(ctx, info), ephemeralStorage(info, amiFamily, blockDeviceMappings, instanceStorePolicy), amiFamily, evictionHard, evictionSoft),
EvictionThreshold: evictionThreshold(memory(ctx, info), ephemeralStorage(info, amiFamily, blockDeviceMappings, instanceStorePolicy), evictionHard),
},
}
if it.Requirements.Compatible(scheduling.NewRequirements(scheduling.NewRequirement(corev1.LabelOSStable, corev1.NodeSelectorOpIn, string(corev1.Windows)))) == nil {
Expand Down Expand Up @@ -529,30 +529,23 @@ func kubeReservedResources(cpus, pods *resource.Quantity, kubeReserved map[strin
}))
}

func evictionThreshold(memory *resource.Quantity, storage *resource.Quantity, amiFamily amifamily.AMIFamily, evictionHard map[string]string, evictionSoft map[string]string) corev1.ResourceList {
func evictionThreshold(memory *resource.Quantity, storage *resource.Quantity, evictionHard map[string]string) corev1.ResourceList {
overhead := corev1.ResourceList{
corev1.ResourceMemory: resource.MustParse("100Mi"),
corev1.ResourceEphemeralStorage: resource.MustParse(fmt.Sprint(math.Ceil(float64(storage.Value()) / 100 * 10))),
}

override := corev1.ResourceList{}
var evictionSignals []map[string]string
// Only use evictionHard for allocatable memory calculation
// evictionSoft should not impact allocatable capacity as it's only a warning threshold
// See: https://kubernetes.io/docs/tasks/administer-cluster/reserve-compute-resources/#eviction-thresholds
if evictionHard != nil {
evictionSignals = append(evictionSignals, evictionHard)
}
if evictionSoft != nil && amiFamily.FeatureFlags().EvictionSoftEnabled {
evictionSignals = append(evictionSignals, evictionSoft)
}

for _, m := range evictionSignals {
temp := corev1.ResourceList{}
if v, ok := m[MemoryAvailable]; ok {
temp[corev1.ResourceMemory] = computeEvictionSignal(*memory, v)
if v, ok := evictionHard[MemoryAvailable]; ok {
override[corev1.ResourceMemory] = computeEvictionSignal(*memory, v)
}
if v, ok := m[NodeFSAvailable]; ok {
temp[corev1.ResourceEphemeralStorage] = computeEvictionSignal(*storage, v)
if v, ok := evictionHard[NodeFSAvailable]; ok {
override[corev1.ResourceEphemeralStorage] = computeEvictionSignal(*storage, v)
}
override = resources.MaxResources(override, temp)
}
// Assign merges maps from left to right so overrides will always be taken last
return lo.Assign(overhead, override)
Expand Down
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