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Merge pull request #104030 from chendave/refactoring_new

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Refactor defaultpreemption for out-of-tree plugins
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Kubernetes Prow Robot 2021-08-11 18:38:00 -07:00 committed by GitHub
commit 27b02a3e37
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5 changed files with 1083 additions and 793 deletions
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45
pkg/scheduler/framework/plugins/defaultpreemption/candidate.go
View File

@ -1,45 +0,0 @@
/*
Copyright 2020 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package defaultpreemption
import (
extenderv1 "k8s.io/kube-scheduler/extender/v1"
)
// Candidate represents a nominated node on which the preemptor can be scheduled,
// along with the list of victims that should be evicted for the preemptor to fit the node.
type Candidate interface {
// Victims wraps a list of to-be-preempted Pods and the number of PDB violation.
Victims() *extenderv1.Victims
// Name returns the target node name where the preemptor gets nominated to run.
Name() string
}
type candidate struct {
victims *extenderv1.Victims
name string
}
// Victims returns s.victims.
func (s *candidate) Victims() *extenderv1.Victims {
return s.victims
}
// Name returns s.name.
func (s *candidate) Name() string {
return s.name
}

607
pkg/scheduler/framework/plugins/defaultpreemption/default_preemption.go
View File

@ -18,15 +18,9 @@ package defaultpreemption
import (
"context"
"errors"
"fmt"
"math"
"math/rand"
"sort"
"sync"
"sync/atomic"
"k8s.io/klog/v2"
v1 "k8s.io/api/core/v1"
policy "k8s.io/api/policy/v1"
@ -34,16 +28,17 @@ import (
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/client-go/informers"
"k8s.io/client-go/kubernetes"
corelisters "k8s.io/client-go/listers/core/v1"
policylisters "k8s.io/client-go/listers/policy/v1"
corev1helpers "k8s.io/component-helpers/scheduling/corev1"
"k8s.io/klog/v2"
extenderv1 "k8s.io/kube-scheduler/extender/v1"
"k8s.io/kubernetes/pkg/scheduler/apis/config"
"k8s.io/kubernetes/pkg/scheduler/apis/config/validation"
"k8s.io/kubernetes/pkg/scheduler/framework"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/feature"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/names"
"k8s.io/kubernetes/pkg/scheduler/framework/preemption"
"k8s.io/kubernetes/pkg/scheduler/metrics"
"k8s.io/kubernetes/pkg/scheduler/util"
)
@ -92,85 +87,15 @@ func (pl *DefaultPreemption) PostFilter(ctx context.Context, state *framework.Cy
metrics.PreemptionAttempts.Inc()
}()
nnn, status := pl.preempt(ctx, state, pod, m)
if !status.IsSuccess() {
return nil, status
pe := preemption.Evaluator{
PluginName: names.DefaultPreemption,
Handler: pl.fh,
PodLister: pl.podLister,
PdbLister: pl.pdbLister,
State: state,
Interface: pl,
}
// This happens when the pod is not eligible for preemption or extenders filtered all candidates.
if nnn == "" {
return nil, framework.NewStatus(framework.Unschedulable)
}
return &framework.PostFilterResult{NominatedNodeName: nnn}, framework.NewStatus(framework.Success)
}
// preempt finds nodes with pods that can be preempted to make room for "pod" to
// schedule. It chooses one of the nodes and preempts the pods on the node and
// returns 1) the node name which is picked up for preemption, 2) any possible error.
// preempt does not update its snapshot. It uses the same snapshot used in the
// scheduling cycle. This is to avoid a scenario where preempt finds feasible
// nodes without preempting any pod. When there are many pending pods in the
// scheduling queue a nominated pod will go back to the queue and behind
// other pods with the same priority. The nominated pod prevents other pods from
// using the nominated resources and the nominated pod could take a long time
// before it is retried after many other pending pods.
func (pl *DefaultPreemption) preempt(ctx context.Context, state *framework.CycleState, pod *v1.Pod, m framework.NodeToStatusMap) (string, *framework.Status) {
cs := pl.fh.ClientSet()
nodeLister := pl.fh.SnapshotSharedLister().NodeInfos()
// 0) Fetch the latest version of <pod>.
// It's safe to directly fetch pod here. Because the informer cache has already been
// initialized when creating the Scheduler obj, i.e., factory.go#MakeDefaultErrorFunc().
// However, tests may need to manually initialize the shared pod informer.
podNamespace, podName := pod.Namespace, pod.Name
pod, err := pl.podLister.Pods(pod.Namespace).Get(pod.Name)
if err != nil {
klog.ErrorS(err, "getting the updated preemptor pod object", "pod", klog.KRef(podNamespace, podName))
return "", framework.AsStatus(err)
}
// 1) Ensure the preemptor is eligible to preempt other pods.
if !PodEligibleToPreemptOthers(pod, nodeLister, m[pod.Status.NominatedNodeName]) {
klog.V(5).InfoS("Pod is not eligible for more preemption", "pod", klog.KObj(pod))
return "", nil
}
// 2) Find all preemption candidates.
candidates, nodeToStatusMap, status := pl.FindCandidates(ctx, state, pod, m)
if !status.IsSuccess() {
return "", status
}
// Return a FitError only when there are no candidates that fit the pod.
if len(candidates) == 0 {
fitError := &framework.FitError{
Pod: pod,
NumAllNodes: len(nodeToStatusMap),
Diagnosis: framework.Diagnosis{
NodeToStatusMap: nodeToStatusMap,
// Leave FailedPlugins as nil as it won't be used on moving Pods.
},
}
return "", framework.NewStatus(framework.Unschedulable, fitError.Error())
}
// 3) Interact with registered Extenders to filter out some candidates if needed.
candidates, status = CallExtenders(pl.fh.Extenders(), pod, nodeLister, candidates)
if !status.IsSuccess() {
return "", status
}
// 4) Find the best candidate.
bestCandidate := SelectCandidate(candidates)
if bestCandidate == nil || len(bestCandidate.Name()) == 0 {
return "", nil
}
// 5) Perform preparation work before nominating the selected candidate.
if status := PrepareCandidate(bestCandidate, pl.fh, cs, pod, pl.Name()); !status.IsSuccess() {
return "", status
}
return bestCandidate.Name(), nil
return pe.Preempt(ctx, pod, m)
}
// calculateNumCandidates returns the number of candidates the FindCandidates
@ -188,248 +113,15 @@ func (pl *DefaultPreemption) calculateNumCandidates(numNodes int32) int32 {
return n
}
// getOffsetAndNumCandidates chooses a random offset and calculates the number
// GetOffsetAndNumCandidates chooses a random offset and calculates the number
// of candidates that should be shortlisted for dry running preemption.
func (pl *DefaultPreemption) getOffsetAndNumCandidates(numNodes int32) (int32, int32) {
func (pl *DefaultPreemption) GetOffsetAndNumCandidates(numNodes int32) (int32, int32) {
return rand.Int31n(numNodes), pl.calculateNumCandidates(numNodes)
}
// FindCandidates calculates a slice of preemption candidates.
// Each candidate is executable to make the given <pod> schedulable.
func (pl *DefaultPreemption) FindCandidates(ctx context.Context, state *framework.CycleState, pod *v1.Pod, m framework.NodeToStatusMap) ([]Candidate, framework.NodeToStatusMap, *framework.Status) {
allNodes, err := pl.fh.SnapshotSharedLister().NodeInfos().List()
if err != nil {
return nil, nil, framework.AsStatus(err)
}
if len(allNodes) == 0 {
return nil, nil, framework.NewStatus(framework.Error, "no nodes available")
}
potentialNodes, unschedulableNodeStatus := nodesWherePreemptionMightHelp(allNodes, m)
if len(potentialNodes) == 0 {
klog.V(3).InfoS("Preemption will not help schedule pod on any node", "pod", klog.KObj(pod))
// In this case, we should clean-up any existing nominated node name of the pod.
if err := util.ClearNominatedNodeName(pl.fh.ClientSet(), pod); err != nil {
klog.ErrorS(err, "cannot clear 'NominatedNodeName' field of pod", "pod", klog.KObj(pod))
// We do not return as this error is not critical.
}
return nil, unschedulableNodeStatus, nil
}
pdbs, err := getPodDisruptionBudgets(pl.pdbLister)
if err != nil {
return nil, nil, framework.AsStatus(err)
}
offset, numCandidates := pl.getOffsetAndNumCandidates(int32(len(potentialNodes)))
if klog.V(5).Enabled() {
var sample []string
for i := offset; i < offset+10 && i < int32(len(potentialNodes)); i++ {
sample = append(sample, potentialNodes[i].Node().Name)
}
klog.Infof("from a pool of %d nodes (offset: %d, sample %d nodes: %v), ~%d candidates will be chosen", len(potentialNodes), offset, len(sample), sample, numCandidates)
}
candidates, nodeStatuses := dryRunPreemption(ctx, pl.fh, state, pod, potentialNodes, pdbs, offset, numCandidates)
for node, status := range unschedulableNodeStatus {
nodeStatuses[node] = status
}
return candidates, nodeStatuses, nil
}
// PodEligibleToPreemptOthers determines whether this pod should be considered
// for preempting other pods or not. If this pod has already preempted other
// pods and those are in their graceful termination period, it shouldn't be
// considered for preemption.
// We look at the node that is nominated for this pod and as long as there are
// terminating pods on the node, we don't consider this for preempting more pods.
func PodEligibleToPreemptOthers(pod *v1.Pod, nodeInfos framework.NodeInfoLister, nominatedNodeStatus *framework.Status) bool {
if pod.Spec.PreemptionPolicy != nil && *pod.Spec.PreemptionPolicy == v1.PreemptNever {
klog.V(5).InfoS("Pod is not eligible for preemption because it has a preemptionPolicy of Never", "pod", klog.KObj(pod))
return false
}
nomNodeName := pod.Status.NominatedNodeName
if len(nomNodeName) > 0 {
// If the pod's nominated node is considered as UnschedulableAndUnresolvable by the filters,
// then the pod should be considered for preempting again.
if nominatedNodeStatus.Code() == framework.UnschedulableAndUnresolvable {
return true
}
if nodeInfo, _ := nodeInfos.Get(nomNodeName); nodeInfo != nil {
podPriority := corev1helpers.PodPriority(pod)
for _, p := range nodeInfo.Pods {
if p.Pod.DeletionTimestamp != nil && corev1helpers.PodPriority(p.Pod) < podPriority {
// There is a terminating pod on the nominated node.
return false
}
}
}
}
return true
}
// nodesWherePreemptionMightHelp returns a list of nodes with failed predicates
// that may be satisfied by removing pods from the node.
func nodesWherePreemptionMightHelp(nodes []*framework.NodeInfo, m framework.NodeToStatusMap) ([]*framework.NodeInfo, framework.NodeToStatusMap) {
var potentialNodes []*framework.NodeInfo
nodeStatuses := make(framework.NodeToStatusMap)
for _, node := range nodes {
name := node.Node().Name
// We rely on the status by each plugin - 'Unschedulable' or 'UnschedulableAndUnresolvable'
// to determine whether preemption may help or not on the node.
if m[name].Code() == framework.UnschedulableAndUnresolvable {
nodeStatuses[node.Node().Name] = framework.NewStatus(framework.UnschedulableAndUnresolvable, "Preemption is not helpful for scheduling")
continue
}
potentialNodes = append(potentialNodes, node)
}
return potentialNodes, nodeStatuses
}
type candidateList struct {
idx int32
items []Candidate
}
func newCandidateList(size int32) *candidateList {
return &candidateList{idx: -1, items: make([]Candidate, size)}
}
// add adds a new candidate to the internal array atomically.
func (cl *candidateList) add(c *candidate) {
if idx := atomic.AddInt32(&cl.idx, 1); idx < int32(len(cl.items)) {
cl.items[idx] = c
}
}
// size returns the number of candidate stored. Note that some add() operations
// might still be executing when this is called, so care must be taken to
// ensure that all add() operations complete before accessing the elements of
// the list.
func (cl *candidateList) size() int32 {
n := atomic.LoadInt32(&cl.idx) + 1
if n >= int32(len(cl.items)) {
n = int32(len(cl.items))
}
return n
}
// get returns the internal candidate array. This function is NOT atomic and
// assumes that all add() operations have been completed.
func (cl *candidateList) get() []Candidate {
return cl.items[:cl.size()]
}
// dryRunPreemption simulates Preemption logic on <potentialNodes> in parallel,
// returns preemption candidates and a map indicating filtered nodes statuses.
// The number of candidates depends on the constraints defined in the plugin's args. In the returned list of
// candidates, ones that do not violate PDB are preferred over ones that do.
func dryRunPreemption(ctx context.Context, fh framework.Handle,
state *framework.CycleState, pod *v1.Pod, potentialNodes []*framework.NodeInfo,
pdbs []*policy.PodDisruptionBudget, offset int32, numCandidates int32) ([]Candidate, framework.NodeToStatusMap) {
nonViolatingCandidates := newCandidateList(numCandidates)
violatingCandidates := newCandidateList(numCandidates)
parallelCtx, cancel := context.WithCancel(ctx)
nodeStatuses := make(framework.NodeToStatusMap)
var statusesLock sync.Mutex
checkNode := func(i int) {
nodeInfoCopy := potentialNodes[(int(offset)+i)%len(potentialNodes)].Clone()
stateCopy := state.Clone()
pods, numPDBViolations, status := selectVictimsOnNode(ctx, fh, stateCopy, pod, nodeInfoCopy, pdbs)
if status.IsSuccess() && len(pods) != 0 {
victims := extenderv1.Victims{
Pods: pods,
NumPDBViolations: int64(numPDBViolations),
}
c := &candidate{
victims: &victims,
name: nodeInfoCopy.Node().Name,
}
if numPDBViolations == 0 {
nonViolatingCandidates.add(c)
} else {
violatingCandidates.add(c)
}
nvcSize, vcSize := nonViolatingCandidates.size(), violatingCandidates.size()
if nvcSize > 0 && nvcSize+vcSize >= numCandidates {
cancel()
}
return
}
if status.IsSuccess() && len(pods) == 0 {
status = framework.AsStatus(fmt.Errorf("expected at least one victim pod on node %q", nodeInfoCopy.Node().Name))
}
statusesLock.Lock()
nodeStatuses[nodeInfoCopy.Node().Name] = status
statusesLock.Unlock()
}
fh.Parallelizer().Until(parallelCtx, len(potentialNodes), checkNode)
return append(nonViolatingCandidates.get(), violatingCandidates.get()...), nodeStatuses
}
// CallExtenders calls given <extenders> to select the list of feasible candidates.
// We will only check <candidates> with extenders that support preemption.
// Extenders which do not support preemption may later prevent preemptor from being scheduled on the nominated
// node. In that case, scheduler will find a different host for the preemptor in subsequent scheduling cycles.
func CallExtenders(extenders []framework.Extender, pod *v1.Pod, nodeLister framework.NodeInfoLister,
candidates []Candidate) ([]Candidate, *framework.Status) {
if len(extenders) == 0 {
return candidates, nil
}
// Migrate candidate slice to victimsMap to adapt to the Extender interface.
// It's only applicable for candidate slice that have unique nominated node name.
victimsMap := candidatesToVictimsMap(candidates)
if len(victimsMap) == 0 {
return candidates, nil
}
for _, extender := range extenders {
if !extender.SupportsPreemption() || !extender.IsInterested(pod) {
continue
}
nodeNameToVictims, err := extender.ProcessPreemption(pod, victimsMap, nodeLister)
if err != nil {
if extender.IsIgnorable() {
klog.InfoS("Skipping extender as it returned error and has ignorable flag set",
"extender", extender, "err", err)
continue
}
return nil, framework.AsStatus(err)
}
// Check if the returned victims are valid.
for nodeName, victims := range nodeNameToVictims {
if victims == nil || len(victims.Pods) == 0 {
if extender.IsIgnorable() {
delete(nodeNameToVictims, nodeName)
klog.InfoS("Ignoring node without victims", "node", nodeName)
continue
}
return nil, framework.AsStatus(fmt.Errorf("expected at least one victim pod on node %q", nodeName))
}
}
// Replace victimsMap with new result after preemption. So the
// rest of extenders can continue use it as parameter.
victimsMap = nodeNameToVictims
// If node list becomes empty, no preemption can happen regardless of other extenders.
if len(victimsMap) == 0 {
break
}
}
var newCandidates []Candidate
for nodeName := range victimsMap {
newCandidates = append(newCandidates, &candidate{
victims: victimsMap[nodeName],
name: nodeName,
})
}
return newCandidates, nil
}
// This function is not applicable for out-of-tree preemption plugins that exercise
// different preemption candidates on the same nominated node.
func candidatesToVictimsMap(candidates []Candidate) map[string]*extenderv1.Victims {
func (pl *DefaultPreemption) CandidatesToVictimsMap(candidates []preemption.Candidate) map[string]*extenderv1.Victims {
m := make(map[string]*extenderv1.Victims)
for _, c := range candidates {
m[c.Name()] = c.Victims()
@ -437,193 +129,20 @@ func candidatesToVictimsMap(candidates []Candidate) map[string]*extenderv1.Victi
return m
}
// SelectCandidate chooses the best-fit candidate from given <candidates> and return it.
func SelectCandidate(candidates []Candidate) Candidate {
if len(candidates) == 0 {
return nil
}
if len(candidates) == 1 {
return candidates[0]
}
victimsMap := candidatesToVictimsMap(candidates)
candidateNode := pickOneNodeForPreemption(victimsMap)
// Same as candidatesToVictimsMap, this logic is not applicable for out-of-tree
// preemption plugins that exercise different candidates on the same nominated node.
if victims := victimsMap[candidateNode]; victims != nil {
return &candidate{
victims: victims,
name: candidateNode,
}
}
// We shouldn't reach here.
klog.ErrorS(errors.New("no candidate selected"), "should not reach here", "candidates", candidates)
// To not break the whole flow, return the first candidate.
return candidates[0]
}
// pickOneNodeForPreemption chooses one node among the given nodes. It assumes
// pods in each map entry are ordered by decreasing priority.
// It picks a node based on the following criteria:
// 1. A node with minimum number of PDB violations.
// 2. A node with minimum highest priority victim is picked.
// 3. Ties are broken by sum of priorities of all victims.
// 4. If there are still ties, node with the minimum number of victims is picked.
// 5. If there are still ties, node with the latest start time of all highest priority victims is picked.
// 6. If there are still ties, the first such node is picked (sort of randomly).
// The 'minNodes1' and 'minNodes2' are being reused here to save the memory
// allocation and garbage collection time.
func pickOneNodeForPreemption(nodesToVictims map[string]*extenderv1.Victims) string {
if len(nodesToVictims) == 0 {
return ""
}
minNumPDBViolatingPods := int64(math.MaxInt32)
var minNodes1 []string
lenNodes1 := 0
for node, victims := range nodesToVictims {
numPDBViolatingPods := victims.NumPDBViolations
if numPDBViolatingPods < minNumPDBViolatingPods {
minNumPDBViolatingPods = numPDBViolatingPods
minNodes1 = nil
lenNodes1 = 0
}
if numPDBViolatingPods == minNumPDBViolatingPods {
minNodes1 = append(minNodes1, node)
lenNodes1++
}
}
if lenNodes1 == 1 {
return minNodes1[0]
}
// There are more than one node with minimum number PDB violating pods. Find
// the one with minimum highest priority victim.
minHighestPriority := int32(math.MaxInt32)
var minNodes2 = make([]string, lenNodes1)
lenNodes2 := 0
for i := 0; i < lenNodes1; i++ {
node := minNodes1[i]
victims := nodesToVictims[node]
// highestPodPriority is the highest priority among the victims on this node.
highestPodPriority := corev1helpers.PodPriority(victims.Pods[0])
if highestPodPriority < minHighestPriority {
minHighestPriority = highestPodPriority
lenNodes2 = 0
}
if highestPodPriority == minHighestPriority {
minNodes2[lenNodes2] = node
lenNodes2++
}
}
if lenNodes2 == 1 {
return minNodes2[0]
}
// There are a few nodes with minimum highest priority victim. Find the
// smallest sum of priorities.
minSumPriorities := int64(math.MaxInt64)
lenNodes1 = 0
for i := 0; i < lenNodes2; i++ {
var sumPriorities int64
node := minNodes2[i]
for _, pod := range nodesToVictims[node].Pods {
// We add MaxInt32+1 to all priorities to make all of them >= 0. This is
// needed so that a node with a few pods with negative priority is not
// picked over a node with a smaller number of pods with the same negative
// priority (and similar scenarios).
sumPriorities += int64(corev1helpers.PodPriority(pod)) + int64(math.MaxInt32+1)
}
if sumPriorities < minSumPriorities {
minSumPriorities = sumPriorities
lenNodes1 = 0
}
if sumPriorities == minSumPriorities {
minNodes1[lenNodes1] = node
lenNodes1++
}
}
if lenNodes1 == 1 {
return minNodes1[0]
}
// There are a few nodes with minimum highest priority victim and sum of priorities.
// Find one with the minimum number of pods.
minNumPods := math.MaxInt32
lenNodes2 = 0
for i := 0; i < lenNodes1; i++ {
node := minNodes1[i]
numPods := len(nodesToVictims[node].Pods)
if numPods < minNumPods {
minNumPods = numPods
lenNodes2 = 0
}
if numPods == minNumPods {
minNodes2[lenNodes2] = node
lenNodes2++
}
}
if lenNodes2 == 1 {
return minNodes2[0]
}
// There are a few nodes with same number of pods.
// Find the node that satisfies latest(earliestStartTime(all highest-priority pods on node))
latestStartTime := util.GetEarliestPodStartTime(nodesToVictims[minNodes2[0]])
if latestStartTime == nil {
// If the earliest start time of all pods on the 1st node is nil, just return it,
// which is not expected to happen.
klog.ErrorS(errors.New("earliestStartTime is nil for node"), "should not reach here", "node", minNodes2[0])
return minNodes2[0]
}
nodeToReturn := minNodes2[0]
for i := 1; i < lenNodes2; i++ {
node := minNodes2[i]
// Get earliest start time of all pods on the current node.
earliestStartTimeOnNode := util.GetEarliestPodStartTime(nodesToVictims[node])
if earliestStartTimeOnNode == nil {
klog.ErrorS(errors.New("earliestStartTime is nil for node"), "should not reach here", "node", node)
continue
}
if earliestStartTimeOnNode.After(latestStartTime.Time) {
latestStartTime = earliestStartTimeOnNode
nodeToReturn = node
}
}
return nodeToReturn
}
// selectVictimsOnNode finds minimum set of pods on the given node that should
// be preempted in order to make enough room for "pod" to be scheduled. The
// minimum set selected is subject to the constraint that a higher-priority pod
// is never preempted when a lower-priority pod could be (higher/lower relative
// to one another, not relative to the preemptor "pod").
// The algorithm first checks if the pod can be scheduled on the node when all the
// lower priority pods are gone. If so, it sorts all the lower priority pods by
// their priority and then puts them into two groups of those whose PodDisruptionBudget
// will be violated if preempted and other non-violating pods. Both groups are
// sorted by priority. It first tries to reprieve as many PDB violating pods as
// possible and then does them same for non-PDB-violating pods while checking
// that the "pod" can still fit on the node.
// NOTE: This function assumes that it is never called if "pod" cannot be scheduled
// due to pod affinity, node affinity, or node anti-affinity reasons. None of
// these predicates can be satisfied by removing more pods from the node.
func selectVictimsOnNode(
// SelectVictimsOnNode finds minimum set of pods on the given node that should be preempted in order to make enough room
// for "pod" to be scheduled.
func (pl *DefaultPreemption) SelectVictimsOnNode(
ctx context.Context,
fh framework.Handle,
state *framework.CycleState,
pod *v1.Pod,
nodeInfo *framework.NodeInfo,
pdbs []*policy.PodDisruptionBudget,
) ([]*v1.Pod, int, *framework.Status) {
pdbs []*policy.PodDisruptionBudget) ([]*v1.Pod, int, *framework.Status) {
var potentialVictims []*framework.PodInfo
removePod := func(rpi *framework.PodInfo) error {
if err := nodeInfo.RemovePod(rpi.Pod); err != nil {
return err
}
status := fh.RunPreFilterExtensionRemovePod(ctx, state, pod, rpi, nodeInfo)
status := pl.fh.RunPreFilterExtensionRemovePod(ctx, state, pod, rpi, nodeInfo)
if !status.IsSuccess() {
return status.AsError()
}
@ -631,7 +150,7 @@ func selectVictimsOnNode(
}
addPod := func(api *framework.PodInfo) error {
nodeInfo.AddPodInfo(api)
status := fh.RunPreFilterExtensionAddPod(ctx, state, pod, api, nodeInfo)
status := pl.fh.RunPreFilterExtensionAddPod(ctx, state, pod, api, nodeInfo)
if !status.IsSuccess() {
return status.AsError()
}
@ -661,7 +180,7 @@ func selectVictimsOnNode(
// inter-pod affinity to one or more victims, but we have decided not to
// support this case for performance reasons. Having affinity to lower
// priority pods is not a recommended configuration anyway.
if status := fh.RunFilterPluginsWithNominatedPods(ctx, state, pod, nodeInfo); !status.IsSuccess() {
if status := pl.fh.RunFilterPluginsWithNominatedPods(ctx, state, pod, nodeInfo); !status.IsSuccess() {
return nil, 0, status
}
var victims []*v1.Pod
@ -675,7 +194,7 @@ func selectVictimsOnNode(
if err := addPod(pi); err != nil {
return false, err
}
status := fh.RunFilterPluginsWithNominatedPods(ctx, state, pod, nodeInfo)
status := pl.fh.RunFilterPluginsWithNominatedPods(ctx, state, pod, nodeInfo)
fits := status.IsSuccess()
if !fits {
if err := removePod(pi); err != nil {
@ -703,60 +222,37 @@ func selectVictimsOnNode(
return victims, numViolatingVictim, framework.NewStatus(framework.Success)
}
// PrepareCandidate does some preparation work before nominating the selected candidate:
// - Evict the victim pods
// - Reject the victim pods if they are in waitingPod map
// - Clear the low-priority pods' nominatedNodeName status if needed
func PrepareCandidate(c Candidate, fh framework.Handle, cs kubernetes.Interface, pod *v1.Pod, pluginName string) *framework.Status {
for _, victim := range c.Victims().Pods {
// If the victim is a WaitingPod, send a reject message to the PermitPlugin.
// Otherwise we should delete the victim.
if waitingPod := fh.GetWaitingPod(victim.UID); waitingPod != nil {
waitingPod.Reject(pluginName, "preempted")
} else if err := util.DeletePod(cs, victim); err != nil {
klog.ErrorS(err, "Preempting pod", "pod", klog.KObj(victim), "preemptor", klog.KObj(pod))
return framework.AsStatus(err)
// PodEligibleToPreemptOthers determines whether this pod should be considered
// for preempting other pods or not. If this pod has already preempted other
// pods and those are in their graceful termination period, it shouldn't be
// considered for preemption.
// We look at the node that is nominated for this pod and as long as there are
// terminating pods on the node, we don't consider this for preempting more pods.
func (pl *DefaultPreemption) PodEligibleToPreemptOthers(pod *v1.Pod, nominatedNodeStatus *framework.Status) bool {
if pod.Spec.PreemptionPolicy != nil && *pod.Spec.PreemptionPolicy == v1.PreemptNever {
klog.V(5).InfoS("Pod is not eligible for preemption because it has a preemptionPolicy of Never", "pod", klog.KObj(pod))
return false
}
nodeInfos := pl.fh.SnapshotSharedLister().NodeInfos()
nomNodeName := pod.Status.NominatedNodeName
if len(nomNodeName) > 0 {
// If the pod's nominated node is considered as UnschedulableAndUnresolvable by the filters,
// then the pod should be considered for preempting again.
if nominatedNodeStatus.Code() == framework.UnschedulableAndUnresolvable {
return true
}
fh.EventRecorder().Eventf(victim, pod, v1.EventTypeNormal, "Preempted", "Preempting", "Preempted by %v/%v on node %v",
pod.Namespace, pod.Name, c.Name())
}
metrics.PreemptionVictims.Observe(float64(len(c.Victims().Pods)))
// Lower priority pods nominated to run on this node, may no longer fit on
// this node. So, we should remove their nomination. Removing their
// nomination updates these pods and moves them to the active queue. It
// lets scheduler find another place for them.
nominatedPods := getLowerPriorityNominatedPods(fh, pod, c.Name())
if err := util.ClearNominatedNodeName(cs, nominatedPods...); err != nil {
klog.ErrorS(err, "cannot clear 'NominatedNodeName' field")
// We do not return as this error is not critical.
}
return nil
}
// getLowerPriorityNominatedPods returns pods whose priority is smaller than the
// priority of the given "pod" and are nominated to run on the given node.
// Note: We could possibly check if the nominated lower priority pods still fit
// and return those that no longer fit, but that would require lots of
// manipulation of NodeInfo and PreFilter state per nominated pod. It may not be
// worth the complexity, especially because we generally expect to have a very
// small number of nominated pods per node.
func getLowerPriorityNominatedPods(pn framework.PodNominator, pod *v1.Pod, nodeName string) []*v1.Pod {
podInfos := pn.NominatedPodsForNode(nodeName)
if len(podInfos) == 0 {
return nil
}
var lowerPriorityPods []*v1.Pod
podPriority := corev1helpers.PodPriority(pod)
for _, pi := range podInfos {
if corev1helpers.PodPriority(pi.Pod) < podPriority {
lowerPriorityPods = append(lowerPriorityPods, pi.Pod)
if nodeInfo, _ := nodeInfos.Get(nomNodeName); nodeInfo != nil {
podPriority := corev1helpers.PodPriority(pod)
for _, p := range nodeInfo.Pods {
if p.Pod.DeletionTimestamp != nil && corev1helpers.PodPriority(p.Pod) < podPriority {
// There is a terminating pod on the nominated node.
return false
}
}
}
}
return lowerPriorityPods
return true
}
// filterPodsWithPDBViolation groups the given "pods" into two groups of "violatingPods"
@ -817,10 +313,3 @@ func getPDBLister(informerFactory informers.SharedInformerFactory, enablePodDisr
}
return nil
}
func getPodDisruptionBudgets(pdbLister policylisters.PodDisruptionBudgetLister) ([]*policy.PodDisruptionBudget, error) {
if pdbLister != nil {
return pdbLister.List(labels.Everything())
}
return nil, nil
}

316
pkg/scheduler/framework/plugins/defaultpreemption/default_preemption_test.go
View File

@ -18,7 +18,6 @@ package defaultpreemption
import (
"context"
"fmt"
"math/rand"
"sort"
"strings"
@ -29,8 +28,8 @@ import (
v1 "k8s.io/api/core/v1"
policy "k8s.io/api/policy/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
apiruntime "k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/util/sets"
"k8s.io/client-go/informers"
clientsetfake "k8s.io/client-go/kubernetes/fake"
@ -38,23 +37,18 @@ import (
"k8s.io/client-go/tools/events"
kubeschedulerconfigv1beta1 "k8s.io/kube-scheduler/config/v1beta1"
extenderv1 "k8s.io/kube-scheduler/extender/v1"
volumescheduling "k8s.io/kubernetes/pkg/controller/volume/scheduling"
"k8s.io/kubernetes/pkg/scheduler/apis/config"
configv1beta1 "k8s.io/kubernetes/pkg/scheduler/apis/config/v1beta1"
"k8s.io/kubernetes/pkg/scheduler/framework"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/defaultbinder"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/feature"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/interpodaffinity"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/nodeaffinity"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/nodelabel"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/nodename"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/names"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/noderesources"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/nodeunschedulable"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/podtopologyspread"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/queuesort"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/tainttoleration"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/volumerestrictions"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/volumezone"
"k8s.io/kubernetes/pkg/scheduler/framework/preemption"
frameworkruntime "k8s.io/kubernetes/pkg/scheduler/framework/runtime"
internalcache "k8s.io/kubernetes/pkg/scheduler/internal/cache"
"k8s.io/kubernetes/pkg/scheduler/internal/parallelize"
@ -99,7 +93,7 @@ func getDefaultDefaultPreemptionArgs() *config.DefaultPreemptionArgs {
return dpa
}
var nodeResourcesFitFunc = func(plArgs apiruntime.Object, fh framework.Handle) (framework.Plugin, error) {
var nodeResourcesFitFunc = func(plArgs runtime.Object, fh framework.Handle) (framework.Plugin, error) {
return noderesources.NewFit(plArgs, fh, feature.Features{})
}
@ -317,8 +311,11 @@ func TestPostFilter(t *testing.T) {
}
}
// TestSelectNodesForPreemption tests dryRunPreemption. This test assumes
// that podsFitsOnNode works correctly and is tested separately.
type candidate struct {
victims *extenderv1.Victims
name string
}
func TestDryRunPreemption(t *testing.T) {
tests := []struct {
name string
@ -330,7 +327,7 @@ func TestDryRunPreemption(t *testing.T) {
pdbs []*policy.PodDisruptionBudget
fakeFilterRC framework.Code // return code for fake filter plugin
disableParallelism bool
expected [][]Candidate
expected [][]candidate
expectedNumFilterCalled []int32
}{
{
@ -346,7 +343,7 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Obj(),
},
expected: [][]Candidate{{}},
expected: [][]candidate{{}},
expectedNumFilterCalled: []int32{2},
},
{
@ -362,7 +359,7 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Obj(),
},
expected: [][]Candidate{{}},
expected: [][]candidate{{}},
fakeFilterRC: framework.Unschedulable,
expectedNumFilterCalled: []int32{2},
},
@ -380,7 +377,7 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Obj(),
},
expected: [][]Candidate{{}},
expected: [][]candidate{{}},
fakeFilterRC: framework.Unschedulable,
expectedNumFilterCalled: []int32{2},
},
@ -397,15 +394,15 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Req(largeRes).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Req(largeRes).Obj(),
},
expected: [][]Candidate{
expected: [][]candidate{
{
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Req(largeRes).Obj()},
},
name: "node1",
},
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Req(largeRes).Obj()},
},
@ -428,7 +425,7 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Req(largeRes).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Req(largeRes).Obj(),
},
expected: [][]Candidate{{}},
expected: [][]candidate{{}},
expectedNumFilterCalled: []int32{0},
},
{
@ -445,15 +442,15 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p1.2").UID("p1.2").Node("node1").Priority(midPriority).Req(largeRes).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Req(largeRes).Obj(),
},
expected: [][]Candidate{
expected: [][]candidate{
{
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p1.2").UID("p1.2").Node("node1").Priority(midPriority).Req(largeRes).Obj()},
},
name: "node1",
},
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Req(largeRes).Obj()},
},
@ -479,9 +476,9 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p1.4").UID("p1.4").Node("node1").Priority(highPriority).Req(smallRes).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(highPriority).Req(largeRes).Obj(),
},
expected: [][]Candidate{
expected: [][]candidate{
{
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{
st.MakePod().Name("p1.2").UID("p1.2").Node("node1").Priority(lowPriority).Req(smallRes).Obj(),
@ -510,9 +507,9 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p1.4").UID("p1.4").Node("node1").Priority(highPriority).Req(smallRes).StartTime(epochTime2).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(highPriority).Req(largeRes).StartTime(epochTime1).Obj(),
},
expected: [][]Candidate{
expected: [][]candidate{
{
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{
st.MakePod().Name("p1.1").UID("p1.1").Node("node1").Priority(lowPriority).Req(smallRes).StartTime(epochTime5).Obj(),
@ -544,9 +541,9 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p1.3").UID("p1.3").Node("node1").Priority(highPriority).Req(smallRes).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(highPriority).Req(smallRes).Obj(),
},
expected: [][]Candidate{
expected: [][]candidate{
{
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{
st.MakePod().Name("p1.1").UID("p1.1").Node("node1").Label("foo", "").Priority(lowPriority).Req(smallRes).
@ -578,15 +575,15 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("pod-x1").UID("pod-x1").Node("node-x").Label("foo", "").Priority(highPriority).Obj(),
st.MakePod().Name("pod-x2").UID("pod-x2").Node("node-x").Label("foo", "").Priority(highPriority).Obj(),
},
expected: [][]Candidate{
expected: [][]candidate{
{
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("pod-a2").UID("pod-a2").Node("node-a").Label("foo", "").Priority(lowPriority).Obj()},
},
name: "node-a",
},
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("pod-b1").UID("pod-b1").Node("node-b").Label("foo", "").Priority(lowPriority).Obj()},
},
@ -596,6 +593,7 @@ func TestDryRunPreemption(t *testing.T) {
},
expectedNumFilterCalled: []int32{5}, // node-a (3), node-b (2), node-x (0)
},
{
name: "get Unschedulable in the preemption phase when the filter plugins filtering the nodes",
registerPlugins: []st.RegisterPluginFunc{
@ -610,7 +608,7 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Req(largeRes).Obj(),
},
fakeFilterRC: framework.Unschedulable,
expected: [][]Candidate{{}},
expected: [][]candidate{{}},
expectedNumFilterCalled: []int32{2},
},
{
@ -632,9 +630,9 @@ func TestDryRunPreemption(t *testing.T) {
Status: policy.PodDisruptionBudgetStatus{DisruptionsAllowed: 1},
},
},
expected: [][]Candidate{
expected: [][]candidate{
{
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{
st.MakePod().Name("p1.1").UID("p1.1").Node("node1").Label("app", "foo").Priority(midPriority).Req(mediumRes).Obj(),
@ -667,9 +665,9 @@ func TestDryRunPreemption(t *testing.T) {
Status: policy.PodDisruptionBudgetStatus{DisruptionsAllowed: 1, DisruptedPods: map[string]metav1.Time{"p2": {Time: time.Now()}}},
},
},
expected: [][]Candidate{
expected: [][]candidate{
{
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{
st.MakePod().Name("p1.1").UID("p1.1").Node("node1").Label("app", "foo").Priority(midPriority).Req(mediumRes).Obj(),
@ -702,9 +700,9 @@ func TestDryRunPreemption(t *testing.T) {
Status: policy.PodDisruptionBudgetStatus{DisruptionsAllowed: 1, DisruptedPods: map[string]metav1.Time{"p1.2": {Time: time.Now()}}},
},
},
expected: [][]Candidate{
expected: [][]candidate{
{
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{
st.MakePod().Name("p1.1").UID("p1.1").Node("node1").Label("app", "foo").Priority(midPriority).Req(mediumRes).Obj(),
@ -738,9 +736,9 @@ func TestDryRunPreemption(t *testing.T) {
Status: policy.PodDisruptionBudgetStatus{DisruptionsAllowed: 1, DisruptedPods: map[string]metav1.Time{"p1.3": {Time: time.Now()}}},
},
},
expected: [][]Candidate{
expected: [][]candidate{
{
&candidate{
candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{
st.MakePod().Name("p1.1").UID("p1.1").Node("node1").Label("app", "foo").Priority(midPriority).Req(mediumRes).Obj(),
@ -773,16 +771,16 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p5").UID("p5").Node("node5").Priority(midPriority).Req(largeRes).Obj(),
},
disableParallelism: true,
expected: [][]Candidate{
expected: [][]candidate{
{
// cycle=0 => offset=4 => node5 (yes), node1 (yes)
&candidate{
candidate{
name: "node1",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Req(largeRes).Obj()},
},
},
&candidate{
candidate{
name: "node5",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p5").UID("p5").Node("node5").Priority(midPriority).Req(largeRes).Obj()},
@ -810,16 +808,16 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p5").UID("p5").Node("node5").Priority(veryHighPriority).Req(largeRes).Obj(),
},
disableParallelism: true,
expected: [][]Candidate{
expected: [][]candidate{
{
// cycle=0 => offset=4 => node5 (no), node1 (yes), node2 (no), node3 (yes)
&candidate{
candidate{
name: "node1",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Req(largeRes).Obj()},
},
},
&candidate{
candidate{
name: "node3",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p3").UID("p3").Node("node3").Priority(midPriority).Req(largeRes).Obj()},
@ -849,16 +847,16 @@ func TestDryRunPreemption(t *testing.T) {
st.MakePod().Name("p5").UID("p5").Node("node5").Priority(midPriority).Req(largeRes).Obj(),
},
disableParallelism: true,
expected: [][]Candidate{
expected: [][]candidate{
{
// cycle=0 => offset=4 => node5 (yes), node1 (yes)
&candidate{
candidate{
name: "node1",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Req(largeRes).Obj()},
},
},
&candidate{
candidate{
name: "node5",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p5").UID("p5").Node("node5").Priority(midPriority).Req(largeRes).Obj()},
@ -867,13 +865,13 @@ func TestDryRunPreemption(t *testing.T) {
},
{
// cycle=1 => offset=1 => node2 (yes), node3 (yes)
&candidate{
candidate{
name: "node2",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Req(largeRes).Obj()},
},
},
&candidate{
candidate{
name: "node3",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p3").UID("p3").Node("node3").Priority(midPriority).Req(largeRes).Obj()},
@ -882,13 +880,13 @@ func TestDryRunPreemption(t *testing.T) {
},
{
// cycle=2 => offset=3 => node4 (yes), node5 (yes)
&candidate{
candidate{
name: "node4",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p4").UID("p4").Node("node4").Priority(midPriority).Req(largeRes).Obj()},
},
},
&candidate{
candidate{
name: "node5",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p5").UID("p5").Node("node5").Priority(midPriority).Req(largeRes).Obj()},
@ -922,7 +920,7 @@ func TestDryRunPreemption(t *testing.T) {
},
},
disableParallelism: true,
expected: [][]Candidate{
expected: [][]candidate{
{
// Even though the DefaultPreemptionArgs constraints suggest that the
// minimum number of candidates is 2, we get three candidates here
@ -931,20 +929,20 @@ func TestDryRunPreemption(t *testing.T) {
// number of additional candidates returned will be at most
// approximately equal to the parallelism in dryRunPreemption).
// cycle=0 => offset=4 => node5 (yes, pdb), node1 (yes, pdb), node2 (no, pdb), node3 (yes)
&candidate{
candidate{
name: "node1",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p1").UID("p1").Node("node1").Label("app", "foo").Priority(midPriority).Req(largeRes).Obj()},
NumPDBViolations: 1,
},
},
&candidate{
candidate{
name: "node3",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p3").UID("p3").Node("node3").Priority(midPriority).Req(largeRes).Obj()},
},
},
&candidate{
candidate{
name: "node5",
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p5").UID("p5").Node("node5").Label("app", "foo").Priority(midPriority).Req(largeRes).Obj()},
@ -1033,7 +1031,12 @@ func TestDryRunPreemption(t *testing.T) {
if tt.args == nil {
tt.args = getDefaultDefaultPreemptionArgs()
}
pl := &DefaultPreemption{args: *tt.args}
pl := &DefaultPreemption{
fh: fwk,
podLister: informerFactory.Core().V1().Pods().Lister(),
pdbLister: getPDBLister(informerFactory, true),
args: *tt.args,
}
// Using 4 as a seed source to test getOffsetAndNumCandidates() deterministically.
// However, we need to do it after informerFactory.WaitforCacheSync() which might
@ -1046,8 +1049,16 @@ func TestDryRunPreemption(t *testing.T) {
if status := fwk.RunPreFilterPlugins(context.Background(), state, pod); !status.IsSuccess() {
t.Errorf("cycle %d: Unexpected PreFilter Status: %v", cycle, status)
}
offset, numCandidates := pl.getOffsetAndNumCandidates(int32(len(nodeInfos)))
got, _ := dryRunPreemption(context.Background(), fwk, state, pod, nodeInfos, tt.pdbs, offset, numCandidates)
pe := preemption.Evaluator{
PluginName: names.DefaultPreemption,
Handler: pl.fh,
PodLister: pl.podLister,
PdbLister: pl.pdbLister,
State: state,
Interface: pl,
}
offset, numCandidates := pl.GetOffsetAndNumCandidates(int32(len(nodeInfos)))
got, _ := pe.DryRunPreemption(context.Background(), pod, nodeInfos, tt.pdbs, offset, numCandidates)
// Sort the values (inner victims) and the candidate itself (by its NominatedNodeName).
for i := range got {
victims := got[i].Victims().Pods
@ -1058,11 +1069,15 @@ func TestDryRunPreemption(t *testing.T) {
sort.Slice(got, func(i, j int) bool {
return got[i].Name() < got[j].Name()
})
candidates := []candidate{}
for i := range got {
candidates = append(candidates, candidate{victims: got[i].Victims(), name: got[i].Name()})
}
if fakePlugin.NumFilterCalled-prevNumFilterCalled != tt.expectedNumFilterCalled[cycle] {
t.Errorf("cycle %d: got NumFilterCalled=%d, want %d", cycle, fakePlugin.NumFilterCalled-prevNumFilterCalled, tt.expectedNumFilterCalled[cycle])
}
prevNumFilterCalled = fakePlugin.NumFilterCalled
if diff := cmp.Diff(tt.expected[cycle], got, cmp.AllowUnexported(candidate{})); diff != "" {
if diff := cmp.Diff(tt.expected[cycle], candidates, cmp.AllowUnexported(candidate{})); diff != "" {
t.Errorf("cycle %d: unexpected candidates (-want, +got): %s", cycle, diff)
}
}
@ -1264,10 +1279,23 @@ func TestSelectBestCandidate(t *testing.T) {
t.Fatal(err)
}
pl := &DefaultPreemption{args: *getDefaultDefaultPreemptionArgs()}
offset, numCandidates := pl.getOffsetAndNumCandidates(int32(len(nodeInfos)))
candidates, _ := dryRunPreemption(context.Background(), fwk, state, tt.pod, nodeInfos, nil, offset, numCandidates)
s := SelectCandidate(candidates)
pl := &DefaultPreemption{
fh: fwk,
podLister: informerFactory.Core().V1().Pods().Lister(),
pdbLister: getPDBLister(informerFactory, true),
args: *getDefaultDefaultPreemptionArgs(),
}
pe := preemption.Evaluator{
PluginName: names.DefaultPreemption,
Handler: pl.fh,
PodLister: pl.podLister,
PdbLister: pl.pdbLister,
State: state,
Interface: pl,
}
offset, numCandidates := pl.GetOffsetAndNumCandidates(int32(len(nodeInfos)))
candidates, _ := pe.DryRunPreemption(context.Background(), tt.pod, nodeInfos, nil, offset, numCandidates)
s := pe.SelectCandidate(candidates)
if s == nil || len(s.Name()) == 0 {
return
}
@ -1334,124 +1362,23 @@ func TestPodEligibleToPreemptOthers(t *testing.T) {
for _, n := range test.nodes {
nodes = append(nodes, st.MakeNode().Name(n).Obj())
}
snapshot := internalcache.NewSnapshot(test.pods, nodes)
if got := PodEligibleToPreemptOthers(test.pod, snapshot.NodeInfos(), test.nominatedNodeStatus); got != test.expected {
registeredPlugins := []st.RegisterPluginFunc{
st.RegisterQueueSortPlugin(queuesort.Name, queuesort.New),
st.RegisterBindPlugin(defaultbinder.Name, defaultbinder.New),
}
f, err := st.NewFramework(registeredPlugins, "",
frameworkruntime.WithSnapshotSharedLister(internalcache.NewSnapshot(test.pods, nodes)),
)
if err != nil {
t.Fatal(err)
}
pl := DefaultPreemption{fh: f}
if got := pl.PodEligibleToPreemptOthers(test.pod, test.nominatedNodeStatus); got != test.expected {
t.Errorf("expected %t, got %t for pod: %s", test.expected, got, test.pod.Name)
}
})
}
}
func TestNodesWherePreemptionMightHelp(t *testing.T) {
// Prepare 4 nodes names.
nodeNames := []string{"node1", "node2", "node3", "node4"}
tests := []struct {
name string
nodesStatuses framework.NodeToStatusMap
expected sets.String // set of expected node names.
}{
{
name: "No node should be attempted",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodeaffinity.ErrReasonPod),
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodename.ErrReason),
"node3": framework.NewStatus(framework.UnschedulableAndUnresolvable, tainttoleration.ErrReasonNotMatch),
"node4": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodelabel.ErrReasonPresenceViolated),
},
expected: sets.NewString(),
},
{
name: "ErrReasonAntiAffinityRulesNotMatch should be tried as it indicates that the pod is unschedulable due to inter-pod anti-affinity",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.Unschedulable, interpodaffinity.ErrReasonAntiAffinityRulesNotMatch),
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodename.ErrReason),
"node3": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodeunschedulable.ErrReasonUnschedulable),
},
expected: sets.NewString("node1", "node4"),
},
{
name: "ErrReasonAffinityRulesNotMatch should not be tried as it indicates that the pod is unschedulable due to inter-pod affinity, but ErrReasonAntiAffinityRulesNotMatch should be tried as it indicates that the pod is unschedulable due to inter-pod anti-affinity",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.UnschedulableAndUnresolvable, interpodaffinity.ErrReasonAffinityRulesNotMatch),
"node2": framework.NewStatus(framework.Unschedulable, interpodaffinity.ErrReasonAntiAffinityRulesNotMatch),
},
expected: sets.NewString("node2", "node3", "node4"),
},
{
name: "Mix of failed predicates works fine",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.UnschedulableAndUnresolvable, volumerestrictions.ErrReasonDiskConflict),
"node2": framework.NewStatus(framework.Unschedulable, fmt.Sprintf("Insufficient %v", v1.ResourceMemory)),
},
expected: sets.NewString("node2", "node3", "node4"),
},
{
name: "Node condition errors should be considered unresolvable",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodeunschedulable.ErrReasonUnknownCondition),
},
expected: sets.NewString("node2", "node3", "node4"),
},
{
name: "ErrVolume... errors should not be tried as it indicates that the pod is unschedulable due to no matching volumes for pod on node",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.UnschedulableAndUnresolvable, volumezone.ErrReasonConflict),
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, string(volumescheduling.ErrReasonNodeConflict)),
"node3": framework.NewStatus(framework.UnschedulableAndUnresolvable, string(volumescheduling.ErrReasonBindConflict)),
},
expected: sets.NewString("node4"),
},
{
name: "ErrReasonConstraintsNotMatch should be tried as it indicates that the pod is unschedulable due to topology spread constraints",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.Unschedulable, podtopologyspread.ErrReasonConstraintsNotMatch),
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodename.ErrReason),
"node3": framework.NewStatus(framework.Unschedulable, podtopologyspread.ErrReasonConstraintsNotMatch),
},
expected: sets.NewString("node1", "node3", "node4"),
},
{
name: "UnschedulableAndUnresolvable status should be skipped but Unschedulable should be tried",
nodesStatuses: framework.NodeToStatusMap{
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, ""),
"node3": framework.NewStatus(framework.Unschedulable, ""),
"node4": framework.NewStatus(framework.UnschedulableAndUnresolvable, ""),
},
expected: sets.NewString("node1", "node3"),
},
{
name: "ErrReasonNodeLabelNotMatch should not be tried as it indicates that the pod is unschedulable due to node doesn't have the required label",
nodesStatuses: framework.NodeToStatusMap{
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, podtopologyspread.ErrReasonNodeLabelNotMatch),
"node3": framework.NewStatus(framework.Unschedulable, ""),
"node4": framework.NewStatus(framework.UnschedulableAndUnresolvable, ""),
},
expected: sets.NewString("node1", "node3"),
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
var nodeInfos []*framework.NodeInfo
for _, name := range nodeNames {
ni := framework.NewNodeInfo()
ni.SetNode(st.MakeNode().Name(name).Obj())
nodeInfos = append(nodeInfos, ni)
}
nodes, _ := nodesWherePreemptionMightHelp(nodeInfos, tt.nodesStatuses)
if len(tt.expected) != len(nodes) {
t.Errorf("number of nodes is not the same as expected. exptectd: %d, got: %d. Nodes: %v", len(tt.expected), len(nodes), nodes)
}
for _, node := range nodes {
name := node.Node().Name
if _, found := tt.expected[name]; !found {
t.Errorf("node %v is not expected.", name)
}
}
})
}
}
func TestPreempt(t *testing.T) {
tests := []struct {
name string
@ -1673,14 +1600,23 @@ func TestPreempt(t *testing.T) {
pdbLister: getPDBLister(informerFactory, true),
args: *getDefaultDefaultPreemptionArgs(),
}
node, status := pl.preempt(context.Background(), state, test.pod, make(framework.NodeToStatusMap))
if !status.IsSuccess() {
pe := preemption.Evaluator{
PluginName: names.DefaultPreemption,
Handler: pl.fh,
PodLister: pl.podLister,
PdbLister: pl.pdbLister,
State: state,
Interface: &pl,
}
res, status := pe.Preempt(context.Background(), test.pod, make(framework.NodeToStatusMap))
if !status.IsSuccess() && !status.IsUnschedulable() {
t.Errorf("unexpected error in preemption: %v", status.AsError())
}
if len(node) != 0 && node != test.expectedNode {
t.Errorf("expected node: %v, got: %v", test.expectedNode, node)
if res != nil && len(res.NominatedNodeName) != 0 && res.NominatedNodeName != test.expectedNode {
t.Errorf("expected node: %v, got: %v", test.expectedNode, res.NominatedNodeName)
}
if len(node) == 0 && len(test.expectedNode) != 0 {
if res != nil && len(res.NominatedNodeName) == 0 && len(test.expectedNode) != 0 {
t.Errorf("expected node: %v, got: nothing", test.expectedNode)
}
if len(deletedPodNames) != len(test.expectedPods) {
@ -1698,7 +1634,9 @@ func TestPreempt(t *testing.T) {
t.Errorf("pod %v is not expected to be a victim.", victimName)
}
}
test.pod.Status.NominatedNodeName = node
if res != nil {
test.pod.Status.NominatedNodeName = res.NominatedNodeName
}
// Manually set the deleted Pods' deletionTimestamp to non-nil.
for _, pod := range test.pods {
@ -1710,12 +1648,12 @@ func TestPreempt(t *testing.T) {
}
// Call preempt again and make sure it doesn't preempt any more pods.
node, status = pl.preempt(context.Background(), state, test.pod, make(framework.NodeToStatusMap))
if !status.IsSuccess() {
res, status = pe.Preempt(context.Background(), test.pod, make(framework.NodeToStatusMap))
if !status.IsSuccess() && !status.IsUnschedulable() {
t.Errorf("unexpected error in preemption: %v", status.AsError())
}
if len(node) != 0 && len(deletedPodNames) > 0 {
t.Errorf("didn't expect any more preemption. Node %v is selected for preemption.", node)
if res != nil && len(deletedPodNames) > 0 {
t.Errorf("didn't expect any more preemption. Node %v is selected for preemption.", res.NominatedNodeName)
}
})
}

574
pkg/scheduler/framework/preemption/preemption.go Normal file
View File

@ -0,0 +1,574 @@
/*
Copyright 2021 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package preemption
import (
"context"
"errors"
"fmt"
"math"
"sync"
"sync/atomic"
v1 "k8s.io/api/core/v1"
policy "k8s.io/api/policy/v1"
"k8s.io/apimachinery/pkg/labels"
corelisters "k8s.io/client-go/listers/core/v1"
policylisters "k8s.io/client-go/listers/policy/v1"
corev1helpers "k8s.io/component-helpers/scheduling/corev1"
"k8s.io/klog/v2"
extenderv1 "k8s.io/kube-scheduler/extender/v1"
"k8s.io/kubernetes/pkg/scheduler/framework"
"k8s.io/kubernetes/pkg/scheduler/metrics"
"k8s.io/kubernetes/pkg/scheduler/util"
)
// Candidate represents a nominated node on which the preemptor can be scheduled,
// along with the list of victims that should be evicted for the preemptor to fit the node.
type Candidate interface {
// Victims wraps a list of to-be-preempted Pods and the number of PDB violation.
Victims() *extenderv1.Victims
// Name returns the target node name where the preemptor gets nominated to run.
Name() string
}
type candidate struct {
victims *extenderv1.Victims
name string
}
// Victims returns s.victims.
func (s *candidate) Victims() *extenderv1.Victims {
return s.victims
}
// Name returns s.name.
func (s *candidate) Name() string {
return s.name
}
type candidateList struct {
idx int32
items []Candidate
}
func newCandidateList(size int32) *candidateList {
return &candidateList{idx: -1, items: make([]Candidate, size)}
}
// add adds a new candidate to the internal array atomically.
func (cl *candidateList) add(c *candidate) {
if idx := atomic.AddInt32(&cl.idx, 1); idx < int32(len(cl.items)) {
cl.items[idx] = c
}
}
// size returns the number of candidate stored. Note that some add() operations
// might still be executing when this is called, so care must be taken to
// ensure that all add() operations complete before accessing the elements of
// the list.
func (cl *candidateList) size() int32 {
n := atomic.LoadInt32(&cl.idx) + 1
if n >= int32(len(cl.items)) {
n = int32(len(cl.items))
}
return n
}
// get returns the internal candidate array. This function is NOT atomic and
// assumes that all add() operations have been completed.
func (cl *candidateList) get() []Candidate {
return cl.items[:cl.size()]
}
// Interface is expected to be implemented by different preemption plugins as all those member
// methods might have different behavior compared with the default preemption.
type Interface interface {
// GetOffsetAndNumCandidates chooses a random offset and calculates the number of candidates that should be
// shortlisted for dry running preemption.
GetOffsetAndNumCandidates(nodes int32) (int32, int32)
// CandidatesToVictimsMap builds a map from the target node to a list of to-be-preempted Pods and the number of PDB violation.
CandidatesToVictimsMap(candidates []Candidate) map[string]*extenderv1.Victims
// PodEligibleToPreemptOthers determines whether this pod should be considered
// for preempting other pods or not.
PodEligibleToPreemptOthers(pod *v1.Pod, nominatedNodeStatus *framework.Status) bool
// SelectVictimsOnNode finds minimum set of pods on the given node that should be preempted in order to make enough room
// for "pod" to be scheduled.
// Note that both `state` and `nodeInfo` are deep copied.
SelectVictimsOnNode(ctx context.Context, state *framework.CycleState,
pod *v1.Pod, nodeInfo *framework.NodeInfo, pdbs []*policy.PodDisruptionBudget) ([]*v1.Pod, int, *framework.Status)
}
type Evaluator struct {
PluginName string
Handler framework.Handle
PodLister corelisters.PodLister
PdbLister policylisters.PodDisruptionBudgetLister
State *framework.CycleState
Interface
}
func (ev *Evaluator) Preempt(ctx context.Context, pod *v1.Pod, m framework.NodeToStatusMap) (*framework.PostFilterResult, *framework.Status) {
// 0) Fetch the latest version of <pod>.
// It's safe to directly fetch pod here. Because the informer cache has already been
// initialized when creating the Scheduler obj, i.e., factory.go#MakeDefaultErrorFunc().
// However, tests may need to manually initialize the shared pod informer.
podNamespace, podName := pod.Namespace, pod.Name
pod, err := ev.PodLister.Pods(pod.Namespace).Get(pod.Name)
if err != nil {
klog.ErrorS(err, "getting the updated preemptor pod object", "pod", klog.KRef(podNamespace, podName))
return nil, framework.AsStatus(err)
}
// 1) Ensure the preemptor is eligible to preempt other pods.
if !ev.PodEligibleToPreemptOthers(pod, m[pod.Status.NominatedNodeName]) {
klog.V(5).InfoS("Pod is not eligible for more preemption", "pod", klog.KObj(pod))
return nil, framework.NewStatus(framework.Unschedulable)
}
// 2) Find all preemption candidates.
candidates, nodeToStatusMap, status := ev.findCandidates(ctx, pod, m)
if !status.IsSuccess() {
return nil, status
}
// Return a FitError only when there are no candidates that fit the pod.
if len(candidates) == 0 {
fitError := &framework.FitError{
Pod: pod,
NumAllNodes: len(nodeToStatusMap),
Diagnosis: framework.Diagnosis{
NodeToStatusMap: nodeToStatusMap,
// Leave FailedPlugins as nil as it won't be used on moving Pods.
},
}
return nil, framework.NewStatus(framework.Unschedulable, fitError.Error())
}
// 3) Interact with registered Extenders to filter out some candidates if needed.
candidates, status = ev.callExtenders(pod, candidates)
if !status.IsSuccess() {
return nil, status
}
// 4) Find the best candidate.
bestCandidate := ev.SelectCandidate(candidates)
if bestCandidate == nil || len(bestCandidate.Name()) == 0 {
return nil, framework.NewStatus(framework.Unschedulable)
}
// 5) Perform preparation work before nominating the selected candidate.
if status := ev.prepareCandidate(bestCandidate, pod, ev.PluginName); !status.IsSuccess() {
return nil, status
}
return &framework.PostFilterResult{NominatedNodeName: bestCandidate.Name()}, framework.NewStatus(framework.Success)
}
// FindCandidates calculates a slice of preemption candidates.
// Each candidate is executable to make the given <pod> schedulable.
func (ev *Evaluator) findCandidates(ctx context.Context, pod *v1.Pod, m framework.NodeToStatusMap) ([]Candidate, framework.NodeToStatusMap, *framework.Status) {
allNodes, err := ev.Handler.SnapshotSharedLister().NodeInfos().List()
if err != nil {
return nil, nil, framework.AsStatus(err)
}
if len(allNodes) == 0 {
return nil, nil, framework.NewStatus(framework.Error, "no nodes available")
}
potentialNodes, unschedulableNodeStatus := nodesWherePreemptionMightHelp(allNodes, m)
if len(potentialNodes) == 0 {
klog.V(3).InfoS("Preemption will not help schedule pod on any node", "pod", klog.KObj(pod))
// In this case, we should clean-up any existing nominated node name of the pod.
if err := util.ClearNominatedNodeName(ev.Handler.ClientSet(), pod); err != nil {
klog.ErrorS(err, "cannot clear 'NominatedNodeName' field of pod", "pod", klog.KObj(pod))
// We do not return as this error is not critical.
}
return nil, unschedulableNodeStatus, nil
}
pdbs, err := getPodDisruptionBudgets(ev.PdbLister)
if err != nil {
return nil, nil, framework.AsStatus(err)
}
offset, numCandidates := ev.GetOffsetAndNumCandidates(int32(len(potentialNodes)))
if klog.V(5).Enabled() {
var sample []string
for i := offset; i < offset+10 && i < int32(len(potentialNodes)); i++ {
sample = append(sample, potentialNodes[i].Node().Name)
}
klog.Infof("from a pool of %d nodes (offset: %d, sample %d nodes: %v), ~%d candidates will be chosen", len(potentialNodes), offset, len(sample), sample, numCandidates)
}
candidates, nodeStatuses := ev.DryRunPreemption(ctx, pod, potentialNodes, pdbs, offset, numCandidates)
for node, status := range unschedulableNodeStatus {
nodeStatuses[node] = status
}
return candidates, nodeStatuses, nil
}
// callExtenders calls given <extenders> to select the list of feasible candidates.
// We will only check <candidates> with extenders that support preemption.
// Extenders which do not support preemption may later prevent preemptor from being scheduled on the nominated
// node. In that case, scheduler will find a different host for the preemptor in subsequent scheduling cycles.
func (ev *Evaluator) callExtenders(pod *v1.Pod, candidates []Candidate) ([]Candidate, *framework.Status) {
extenders := ev.Handler.Extenders()
nodeLister := ev.Handler.SnapshotSharedLister().NodeInfos()
if len(extenders) == 0 {
return candidates, nil
}
// Migrate candidate slice to victimsMap to adapt to the Extender interface.
// It's only applicable for candidate slice that have unique nominated node name.
victimsMap := ev.CandidatesToVictimsMap(candidates)
if len(victimsMap) == 0 {
return candidates, nil
}
for _, extender := range extenders {
if !extender.SupportsPreemption() || !extender.IsInterested(pod) {
continue
}
nodeNameToVictims, err := extender.ProcessPreemption(pod, victimsMap, nodeLister)
if err != nil {
if extender.IsIgnorable() {
klog.InfoS("Skipping extender as it returned error and has ignorable flag set",
"extender", extender, "err", err)
continue
}
return nil, framework.AsStatus(err)
}
// Check if the returned victims are valid.
for nodeName, victims := range nodeNameToVictims {
if victims == nil || len(victims.Pods) == 0 {
if extender.IsIgnorable() {
delete(nodeNameToVictims, nodeName)
klog.InfoS("Ignoring node without victims", "node", nodeName)
continue
}
return nil, framework.AsStatus(fmt.Errorf("expected at least one victim pod on node %q", nodeName))
}
}
// Replace victimsMap with new result after preemption. So the
// rest of extenders can continue use it as parameter.
victimsMap = nodeNameToVictims
// If node list becomes empty, no preemption can happen regardless of other extenders.
if len(victimsMap) == 0 {
break
}
}
var newCandidates []Candidate
for nodeName := range victimsMap {
newCandidates = append(newCandidates, &candidate{
victims: victimsMap[nodeName],
name: nodeName,
})
}
return newCandidates, nil
}
// SelectCandidate chooses the best-fit candidate from given <candidates> and return it.
// NOTE: This method is exported for easier testing in default preemption.
func (ev *Evaluator) SelectCandidate(candidates []Candidate) Candidate {
if len(candidates) == 0 {
return nil
}
if len(candidates) == 1 {
return candidates[0]
}
victimsMap := ev.CandidatesToVictimsMap(candidates)
candidateNode := pickOneNodeForPreemption(victimsMap)
// Same as candidatesToVictimsMap, this logic is not applicable for out-of-tree
// preemption plugins that exercise different candidates on the same nominated node.
if victims := victimsMap[candidateNode]; victims != nil {
return &candidate{
victims: victims,
name: candidateNode,
}
}
// We shouldn't reach here.
klog.ErrorS(errors.New("no candidate selected"), "should not reach here", "candidates", candidates)
// To not break the whole flow, return the first candidate.
return candidates[0]
}
// prepareCandidate does some preparation work before nominating the selected candidate:
// - Evict the victim pods
// - Reject the victim pods if they are in waitingPod map
// - Clear the low-priority pods' nominatedNodeName status if needed
func (ev *Evaluator) prepareCandidate(c Candidate, pod *v1.Pod, pluginName string) *framework.Status {
fh := ev.Handler
cs := ev.Handler.ClientSet()
for _, victim := range c.Victims().Pods {
// If the victim is a WaitingPod, send a reject message to the PermitPlugin.
// Otherwise we should delete the victim.
if waitingPod := fh.GetWaitingPod(victim.UID); waitingPod != nil {
waitingPod.Reject(pluginName, "preempted")
} else if err := util.DeletePod(cs, victim); err != nil {
klog.ErrorS(err, "Preempting pod", "pod", klog.KObj(victim), "preemptor", klog.KObj(pod))
return framework.AsStatus(err)
}
fh.EventRecorder().Eventf(victim, pod, v1.EventTypeNormal, "Preempted", "Preempting", "Preempted by %v/%v on node %v",
pod.Namespace, pod.Name, c.Name())
}
metrics.PreemptionVictims.Observe(float64(len(c.Victims().Pods)))
// Lower priority pods nominated to run on this node, may no longer fit on
// this node. So, we should remove their nomination. Removing their
// nomination updates these pods and moves them to the active queue. It
// lets scheduler find another place for them.
nominatedPods := getLowerPriorityNominatedPods(fh, pod, c.Name())
if err := util.ClearNominatedNodeName(cs, nominatedPods...); err != nil {
klog.ErrorS(err, "cannot clear 'NominatedNodeName' field")
// We do not return as this error is not critical.
}
return nil
}
// nodesWherePreemptionMightHelp returns a list of nodes with failed predicates
// that may be satisfied by removing pods from the node.
func nodesWherePreemptionMightHelp(nodes []*framework.NodeInfo, m framework.NodeToStatusMap) ([]*framework.NodeInfo, framework.NodeToStatusMap) {
var potentialNodes []*framework.NodeInfo
nodeStatuses := make(framework.NodeToStatusMap)
for _, node := range nodes {
name := node.Node().Name
// We rely on the status by each plugin - 'Unschedulable' or 'UnschedulableAndUnresolvable'
// to determine whether preemption may help or not on the node.
if m[name].Code() == framework.UnschedulableAndUnresolvable {
nodeStatuses[node.Node().Name] = framework.NewStatus(framework.UnschedulableAndUnresolvable, "Preemption is not helpful for scheduling")
continue
}
potentialNodes = append(potentialNodes, node)
}
return potentialNodes, nodeStatuses
}
func getPodDisruptionBudgets(pdbLister policylisters.PodDisruptionBudgetLister) ([]*policy.PodDisruptionBudget, error) {
if pdbLister != nil {
return pdbLister.List(labels.Everything())
}
return nil, nil
}
// pickOneNodeForPreemption chooses one node among the given nodes. It assumes
// pods in each map entry are ordered by decreasing priority.
// It picks a node based on the following criteria:
// 1. A node with minimum number of PDB violations.
// 2. A node with minimum highest priority victim is picked.
// 3. Ties are broken by sum of priorities of all victims.
// 4. If there are still ties, node with the minimum number of victims is picked.
// 5. If there are still ties, node with the latest start time of all highest priority victims is picked.
// 6. If there are still ties, the first such node is picked (sort of randomly).
// The 'minNodes1' and 'minNodes2' are being reused here to save the memory
// allocation and garbage collection time.
func pickOneNodeForPreemption(nodesToVictims map[string]*extenderv1.Victims) string {
if len(nodesToVictims) == 0 {
return ""
}
minNumPDBViolatingPods := int64(math.MaxInt32)
var minNodes1 []string
lenNodes1 := 0
for node, victims := range nodesToVictims {
numPDBViolatingPods := victims.NumPDBViolations
if numPDBViolatingPods < minNumPDBViolatingPods {
minNumPDBViolatingPods = numPDBViolatingPods
minNodes1 = nil
lenNodes1 = 0
}
if numPDBViolatingPods == minNumPDBViolatingPods {
minNodes1 = append(minNodes1, node)
lenNodes1++
}
}
if lenNodes1 == 1 {
return minNodes1[0]
}
// There are more than one node with minimum number PDB violating pods. Find
// the one with minimum highest priority victim.
minHighestPriority := int32(math.MaxInt32)
var minNodes2 = make([]string, lenNodes1)
lenNodes2 := 0
for i := 0; i < lenNodes1; i++ {
node := minNodes1[i]
victims := nodesToVictims[node]
// highestPodPriority is the highest priority among the victims on this node.
highestPodPriority := corev1helpers.PodPriority(victims.Pods[0])
if highestPodPriority < minHighestPriority {
minHighestPriority = highestPodPriority
lenNodes2 = 0
}
if highestPodPriority == minHighestPriority {
minNodes2[lenNodes2] = node
lenNodes2++
}
}
if lenNodes2 == 1 {
return minNodes2[0]
}
// There are a few nodes with minimum highest priority victim. Find the
// smallest sum of priorities.
minSumPriorities := int64(math.MaxInt64)
lenNodes1 = 0
for i := 0; i < lenNodes2; i++ {
var sumPriorities int64
node := minNodes2[i]
for _, pod := range nodesToVictims[node].Pods {
// We add MaxInt32+1 to all priorities to make all of them >= 0. This is
// needed so that a node with a few pods with negative priority is not
// picked over a node with a smaller number of pods with the same negative
// priority (and similar scenarios).
sumPriorities += int64(corev1helpers.PodPriority(pod)) + int64(math.MaxInt32+1)
}
if sumPriorities < minSumPriorities {
minSumPriorities = sumPriorities
lenNodes1 = 0
}
if sumPriorities == minSumPriorities {
minNodes1[lenNodes1] = node
lenNodes1++
}
}
if lenNodes1 == 1 {
return minNodes1[0]
}
// There are a few nodes with minimum highest priority victim and sum of priorities.
// Find one with the minimum number of pods.
minNumPods := math.MaxInt32
lenNodes2 = 0
for i := 0; i < lenNodes1; i++ {
node := minNodes1[i]
numPods := len(nodesToVictims[node].Pods)
if numPods < minNumPods {
minNumPods = numPods
lenNodes2 = 0
}
if numPods == minNumPods {
minNodes2[lenNodes2] = node
lenNodes2++
}
}
if lenNodes2 == 1 {
return minNodes2[0]
}
// There are a few nodes with same number of pods.
// Find the node that satisfies latest(earliestStartTime(all highest-priority pods on node))
latestStartTime := util.GetEarliestPodStartTime(nodesToVictims[minNodes2[0]])
if latestStartTime == nil {
// If the earliest start time of all pods on the 1st node is nil, just return it,
// which is not expected to happen.
klog.ErrorS(errors.New("earliestStartTime is nil for node"), "should not reach here", "node", minNodes2[0])
return minNodes2[0]
}
nodeToReturn := minNodes2[0]
for i := 1; i < lenNodes2; i++ {
node := minNodes2[i]
// Get earliest start time of all pods on the current node.
earliestStartTimeOnNode := util.GetEarliestPodStartTime(nodesToVictims[node])
if earliestStartTimeOnNode == nil {
klog.ErrorS(errors.New("earliestStartTime is nil for node"), "should not reach here", "node", node)
continue
}
if earliestStartTimeOnNode.After(latestStartTime.Time) {
latestStartTime = earliestStartTimeOnNode
nodeToReturn = node
}
}
return nodeToReturn
}
// getLowerPriorityNominatedPods returns pods whose priority is smaller than the
// priority of the given "pod" and are nominated to run on the given node.
// Note: We could possibly check if the nominated lower priority pods still fit
// and return those that no longer fit, but that would require lots of
// manipulation of NodeInfo and PreFilter state per nominated pod. It may not be
// worth the complexity, especially because we generally expect to have a very
// small number of nominated pods per node.
func getLowerPriorityNominatedPods(pn framework.PodNominator, pod *v1.Pod, nodeName string) []*v1.Pod {
podInfos := pn.NominatedPodsForNode(nodeName)
if len(podInfos) == 0 {
return nil
}
var lowerPriorityPods []*v1.Pod
podPriority := corev1helpers.PodPriority(pod)
for _, pi := range podInfos {
if corev1helpers.PodPriority(pi.Pod) < podPriority {
lowerPriorityPods = append(lowerPriorityPods, pi.Pod)
}
}
return lowerPriorityPods
}
// DryRunPreemption simulates Preemption logic on <potentialNodes> in parallel,
// returns preemption candidates and a map indicating filtered nodes statuses.
// The number of candidates depends on the constraints defined in the plugin's args. In the returned list of
// candidates, ones that do not violate PDB are preferred over ones that do.
// NOTE: This method is exported for easier testing in default preemption.
func (ev *Evaluator) DryRunPreemption(ctx context.Context, pod *v1.Pod, potentialNodes []*framework.NodeInfo,
pdbs []*policy.PodDisruptionBudget, offset int32, numCandidates int32) ([]Candidate, framework.NodeToStatusMap) {
fh := ev.Handler
nonViolatingCandidates := newCandidateList(numCandidates)
violatingCandidates := newCandidateList(numCandidates)
parallelCtx, cancel := context.WithCancel(ctx)
nodeStatuses := make(framework.NodeToStatusMap)
var statusesLock sync.Mutex
checkNode := func(i int) {
nodeInfoCopy := potentialNodes[(int(offset)+i)%len(potentialNodes)].Clone()
stateCopy := ev.State.Clone()
pods, numPDBViolations, status := ev.SelectVictimsOnNode(ctx, stateCopy, pod, nodeInfoCopy, pdbs)
if status.IsSuccess() && len(pods) != 0 {
victims := extenderv1.Victims{
Pods: pods,
NumPDBViolations: int64(numPDBViolations),
}
c := &candidate{
victims: &victims,
name: nodeInfoCopy.Node().Name,
}
if numPDBViolations == 0 {
nonViolatingCandidates.add(c)
} else {
violatingCandidates.add(c)
}
nvcSize, vcSize := nonViolatingCandidates.size(), violatingCandidates.size()
if nvcSize > 0 && nvcSize+vcSize >= numCandidates {
cancel()
}
return
}
if status.IsSuccess() && len(pods) == 0 {
status = framework.AsStatus(fmt.Errorf("expected at least one victim pod on node %q", nodeInfoCopy.Node().Name))
}
statusesLock.Lock()
nodeStatuses[nodeInfoCopy.Node().Name] = status
statusesLock.Unlock()
}
fh.Parallelizer().Until(parallelCtx, len(potentialNodes), checkNode)
return append(nonViolatingCandidates.get(), violatingCandidates.get()...), nodeStatuses
}

334
pkg/scheduler/framework/preemption/preemption_test.go Normal file
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@ -0,0 +1,334 @@
/*
Copyright 2021 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package preemption
import (
"context"
"fmt"
"sort"
"testing"
"github.com/google/go-cmp/cmp"
v1 "k8s.io/api/core/v1"
policy "k8s.io/api/policy/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/util/sets"
"k8s.io/client-go/informers"
clientsetfake "k8s.io/client-go/kubernetes/fake"
extenderv1 "k8s.io/kube-scheduler/extender/v1"
volumescheduling "k8s.io/kubernetes/pkg/controller/volume/scheduling"
"k8s.io/kubernetes/pkg/scheduler/framework"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/defaultbinder"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/interpodaffinity"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/nodeaffinity"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/nodelabel"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/nodename"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/nodeunschedulable"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/podtopologyspread"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/queuesort"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/tainttoleration"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/volumerestrictions"
"k8s.io/kubernetes/pkg/scheduler/framework/plugins/volumezone"
frameworkruntime "k8s.io/kubernetes/pkg/scheduler/framework/runtime"
internalcache "k8s.io/kubernetes/pkg/scheduler/internal/cache"
"k8s.io/kubernetes/pkg/scheduler/internal/parallelize"
internalqueue "k8s.io/kubernetes/pkg/scheduler/internal/queue"
st "k8s.io/kubernetes/pkg/scheduler/testing"
)
var (
midPriority, highPriority = int32(100), int32(1000)
veryLargeRes = map[v1.ResourceName]string{
v1.ResourceCPU: "500m",
v1.ResourceMemory: "500",
}
)
type FakePostFilterPlugin struct {
numViolatingVictim int
}
func (pl *FakePostFilterPlugin) SelectVictimsOnNode(
ctx context.Context, state *framework.CycleState, pod *v1.Pod,
nodeInfo *framework.NodeInfo, pdbs []*policy.PodDisruptionBudget) (victims []*v1.Pod, numViolatingVictim int, staus *framework.Status) {
return append(victims, nodeInfo.Pods[0].Pod), pl.numViolatingVictim, nil
}
func (pl *FakePostFilterPlugin) GetOffsetAndNumCandidates(nodes int32) (int32, int32) {
return 0, nodes
}
func (pl *FakePostFilterPlugin) CandidatesToVictimsMap(candidates []Candidate) map[string]*extenderv1.Victims {
return nil
}
func (pl *FakePostFilterPlugin) PodEligibleToPreemptOthers(pod *v1.Pod, nominatedNodeStatus *framework.Status) bool {
return true
}
func TestNodesWherePreemptionMightHelp(t *testing.T) {
// Prepare 4 nodes names.
nodeNames := []string{"node1", "node2", "node3", "node4"}
tests := []struct {
name string
nodesStatuses framework.NodeToStatusMap
expected sets.String // set of expected node names.
}{
{
name: "No node should be attempted",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodeaffinity.ErrReasonPod),
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodename.ErrReason),
"node3": framework.NewStatus(framework.UnschedulableAndUnresolvable, tainttoleration.ErrReasonNotMatch),
"node4": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodelabel.ErrReasonPresenceViolated),
},
expected: sets.NewString(),
},
{
name: "ErrReasonAntiAffinityRulesNotMatch should be tried as it indicates that the pod is unschedulable due to inter-pod anti-affinity",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.Unschedulable, interpodaffinity.ErrReasonAntiAffinityRulesNotMatch),
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodename.ErrReason),
"node3": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodeunschedulable.ErrReasonUnschedulable),
},
expected: sets.NewString("node1", "node4"),
},
{
name: "ErrReasonAffinityRulesNotMatch should not be tried as it indicates that the pod is unschedulable due to inter-pod affinity, but ErrReasonAntiAffinityRulesNotMatch should be tried as it indicates that the pod is unschedulable due to inter-pod anti-affinity",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.UnschedulableAndUnresolvable, interpodaffinity.ErrReasonAffinityRulesNotMatch),
"node2": framework.NewStatus(framework.Unschedulable, interpodaffinity.ErrReasonAntiAffinityRulesNotMatch),
},
expected: sets.NewString("node2", "node3", "node4"),
},
{
name: "Mix of failed predicates works fine",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.UnschedulableAndUnresolvable, volumerestrictions.ErrReasonDiskConflict),
"node2": framework.NewStatus(framework.Unschedulable, fmt.Sprintf("Insufficient %v", v1.ResourceMemory)),
},
expected: sets.NewString("node2", "node3", "node4"),
},
{
name: "Node condition errors should be considered unresolvable",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodeunschedulable.ErrReasonUnknownCondition),
},
expected: sets.NewString("node2", "node3", "node4"),
},
{
name: "ErrVolume... errors should not be tried as it indicates that the pod is unschedulable due to no matching volumes for pod on node",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.UnschedulableAndUnresolvable, volumezone.ErrReasonConflict),
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, string(volumescheduling.ErrReasonNodeConflict)),
"node3": framework.NewStatus(framework.UnschedulableAndUnresolvable, string(volumescheduling.ErrReasonBindConflict)),
},
expected: sets.NewString("node4"),
},
{
name: "ErrReasonConstraintsNotMatch should be tried as it indicates that the pod is unschedulable due to topology spread constraints",
nodesStatuses: framework.NodeToStatusMap{
"node1": framework.NewStatus(framework.Unschedulable, podtopologyspread.ErrReasonConstraintsNotMatch),
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, nodename.ErrReason),
"node3": framework.NewStatus(framework.Unschedulable, podtopologyspread.ErrReasonConstraintsNotMatch),
},
expected: sets.NewString("node1", "node3", "node4"),
},
{
name: "UnschedulableAndUnresolvable status should be skipped but Unschedulable should be tried",
nodesStatuses: framework.NodeToStatusMap{
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, ""),
"node3": framework.NewStatus(framework.Unschedulable, ""),
"node4": framework.NewStatus(framework.UnschedulableAndUnresolvable, ""),
},
expected: sets.NewString("node1", "node3"),
},
{
name: "ErrReasonNodeLabelNotMatch should not be tried as it indicates that the pod is unschedulable due to node doesn't have the required label",
nodesStatuses: framework.NodeToStatusMap{
"node2": framework.NewStatus(framework.UnschedulableAndUnresolvable, podtopologyspread.ErrReasonNodeLabelNotMatch),
"node3": framework.NewStatus(framework.Unschedulable, ""),
"node4": framework.NewStatus(framework.UnschedulableAndUnresolvable, ""),
},
expected: sets.NewString("node1", "node3"),
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
var nodeInfos []*framework.NodeInfo
for _, name := range nodeNames {
ni := framework.NewNodeInfo()
ni.SetNode(st.MakeNode().Name(name).Obj())
nodeInfos = append(nodeInfos, ni)
}
nodes, _ := nodesWherePreemptionMightHelp(nodeInfos, tt.nodesStatuses)
if len(tt.expected) != len(nodes) {
t.Errorf("number of nodes is not the same as expected. exptectd: %d, got: %d. Nodes: %v", len(tt.expected), len(nodes), nodes)
}
for _, node := range nodes {
name := node.Node().Name
if _, found := tt.expected[name]; !found {
t.Errorf("node %v is not expected.", name)
}
}
})
}
}
func TestDryRunPreemption(t *testing.T) {
tests := []struct {
name string
nodes []*v1.Node
testPods []*v1.Pod
initPods []*v1.Pod
numViolatingVictim int
expected [][]Candidate
}{
{
name: "no pdb violation",
nodes: []*v1.Node{
st.MakeNode().Name("node1").Capacity(veryLargeRes).Obj(),
st.MakeNode().Name("node2").Capacity(veryLargeRes).Obj(),
},
testPods: []*v1.Pod{
st.MakePod().Name("p").UID("p").Priority(highPriority).Obj(),
},
initPods: []*v1.Pod{
st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Obj(),
},
expected: [][]Candidate{
{
&candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Obj()},
},
name: "node1",
},
&candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Obj()},
},
name: "node2",
},
},
},
},
{
name: "pdb violation on each node",
nodes: []*v1.Node{
st.MakeNode().Name("node1").Capacity(veryLargeRes).Obj(),
st.MakeNode().Name("node2").Capacity(veryLargeRes).Obj(),
},
testPods: []*v1.Pod{
st.MakePod().Name("p").UID("p").Priority(highPriority).Obj(),
},
initPods: []*v1.Pod{
st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Obj(),
st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Obj(),
},
numViolatingVictim: 1,
expected: [][]Candidate{
{
&candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p1").UID("p1").Node("node1").Priority(midPriority).Obj()},
NumPDBViolations: 1,
},
name: "node1",
},
&candidate{
victims: &extenderv1.Victims{
Pods: []*v1.Pod{st.MakePod().Name("p2").UID("p2").Node("node2").Priority(midPriority).Obj()},
NumPDBViolations: 1,
},
name: "node2",
},
},
},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
registeredPlugins := append([]st.RegisterPluginFunc{
st.RegisterQueueSortPlugin(queuesort.Name, queuesort.New)},
st.RegisterBindPlugin(defaultbinder.Name, defaultbinder.New),
)
var objs []runtime.Object
for _, p := range append(tt.testPods, tt.initPods...) {
objs = append(objs, p)
}
for _, n := range tt.nodes {
objs = append(objs, n)
}
informerFactory := informers.NewSharedInformerFactory(clientsetfake.NewSimpleClientset(objs...), 0)
parallelism := parallelize.DefaultParallelism
fwk, err := st.NewFramework(
registeredPlugins, "",
frameworkruntime.WithPodNominator(internalqueue.NewPodNominator(informerFactory.Core().V1().Pods().Lister())),
frameworkruntime.WithInformerFactory(informerFactory),
frameworkruntime.WithParallelism(parallelism),
frameworkruntime.WithSnapshotSharedLister(internalcache.NewSnapshot(tt.testPods, tt.nodes)),
)
if err != nil {
t.Fatal(err)
}
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
informerFactory.Start(ctx.Done())
informerFactory.WaitForCacheSync(ctx.Done())
snapshot := internalcache.NewSnapshot(tt.initPods, tt.nodes)
nodeInfos, err := snapshot.NodeInfos().List()
if err != nil {
t.Fatal(err)
}
sort.Slice(nodeInfos, func(i, j int) bool {
return nodeInfos[i].Node().Name < nodeInfos[j].Node().Name
})
fakePostPlugin := &FakePostFilterPlugin{numViolatingVictim: tt.numViolatingVictim}
for cycle, pod := range tt.testPods {
state := framework.NewCycleState()
pe := Evaluator{
PluginName: "FakePostFilter",
Handler: fwk,
Interface: fakePostPlugin,
State: state,
}
got, _ := pe.DryRunPreemption(context.Background(), pod, nodeInfos, nil, 0, int32(len(nodeInfos)))
// Sort the values (inner victims) and the candidate itself (by its NominatedNodeName).
for i := range got {
victims := got[i].Victims().Pods
sort.Slice(victims, func(i, j int) bool {
return victims[i].Name < victims[j].Name
})
}
sort.Slice(got, func(i, j int) bool {
return got[i].Name() < got[j].Name()
})
if diff := cmp.Diff(tt.expected[cycle], got, cmp.AllowUnexported(candidate{})); diff != "" {
t.Errorf("cycle %d: unexpected candidates (-want, +got): %s", cycle, diff)
}
}
})
}
}