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fix: topologyspreadconstraint to prefer evictable before sorting domains

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Sort pods that are above ideal avg based on the criteria that they fit on other nodes that are below avg

Signed-off-by: Amir Alavi <amiralavi7@gmail.com>
This commit is contained in:
Amir Alavi
2025-07-10 17:26:19 -04:00
parent e5ab156a99
commit fbf11df729
2 changed files with 86 additions and 27 deletions
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9
pkg/framework/plugins/removepodsviolatingtopologyspreadconstraint/topologyspreadconstraint.go
View File

@@ -356,9 +356,17 @@ func (d *RemovePodsViolatingTopologySpreadConstraint) balanceDomains(
continue
}
// prefer pods above the ideal average to be those that fit on nodes that are below ideal avg (need more pods)
sort.SliceStable(sortedDomains[j].pods, func(a, b int) bool {
canEvictA := node.PodFitsAnyOtherNode(getPodsAssignedToNode, sortedDomains[j].pods[a], nodesBelowIdealAvg)
canEvictB := node.PodFitsAnyOtherNode(getPodsAssignedToNode, sortedDomains[j].pods[b], nodesBelowIdealAvg)
return !canEvictA && canEvictB
})
// remove pods from the higher topology and add them to the list of pods to be evicted
// also (just for tracking), add them to the list of pods in the lower topology
aboveToEvict := sortedDomains[j].pods[len(sortedDomains[j].pods)-movePods:]
for k := range aboveToEvict {
// PodFitsAnyOtherNode excludes the current node because, for the sake of domain balancing only, we care about if there is any other
// place it could theoretically fit.
@@ -429,6 +437,7 @@ func sortDomains(constraintTopologyPairs map[topologyPair][]*v1.Pod, isEvictable
// if true and both and non-evictable, order doesn't matter
return !(evictableI && !evictableJ)
}
hasSelectorOrAffinityI := hasSelectorOrAffinity(*list[i])
hasSelectorOrAffinityJ := hasSelectorOrAffinity(*list[j])
// if both pods have selectors/affinity, compare them by their priority

104
pkg/framework/plugins/removepodsviolatingtopologyspreadconstraint/topologyspreadconstraint_test.go
View File

@@ -1399,6 +1399,63 @@ func TestTopologySpreadConstraint(t *testing.T) {
args: RemovePodsViolatingTopologySpreadConstraintArgs{},
nodeFit: true,
},
{
name: "3 domains, sizes [2, 1, 0] with selectors, maxSkew=1, nodeTaintsPolicy=Ignore, should move 1 for [1, 1, 1]",
nodes: []*v1.Node{
test.BuildTestNode("A1", 1000, 2000, 9, func(n *v1.Node) {
n.Labels["zone"] = "zoneA"
n.Labels[v1.LabelArchStable] = "arm64"
}),
test.BuildTestNode("B1", 1000, 2000, 9, func(n *v1.Node) {
n.Labels["zone"] = "zoneB"
n.Labels[v1.LabelArchStable] = "arm64"
}),
test.BuildTestNode("C1", 1000, 2000, 9, func(n *v1.Node) {
n.Labels["zone"] = "zoneC"
n.Labels[v1.LabelArchStable] = "arm64"
}),
},
pods: createTestPods([]testPodList{
{
count: 1,
node: "A1",
labels: map[string]string{"foo": "bar"},
constraints: getDefaultTopologyConstraints(1, func(constraint *v1.TopologySpreadConstraint) {
constraint.NodeAffinityPolicy = utilptr.To(v1.NodeInclusionPolicyIgnore)
}),
nodeSelector: map[string]string{
v1.LabelArchStable: "arm64",
},
},
{
count: 1,
node: "A1",
labels: map[string]string{"foo": "bar"},
constraints: getDefaultTopologyConstraints(1, func(constraint *v1.TopologySpreadConstraint) {
constraint.NodeAffinityPolicy = utilptr.To(v1.NodeInclusionPolicyIgnore)
}),
nodeSelector: map[string]string{
"zone": "zoneA",
v1.LabelArchStable: "arm64",
},
},
{
count: 1,
node: "B1",
labels: map[string]string{"foo": "bar"},
constraints: getDefaultTopologyConstraints(1, func(constraint *v1.TopologySpreadConstraint) {
constraint.NodeAffinityPolicy = utilptr.To(v1.NodeInclusionPolicyIgnore)
}),
nodeSelector: map[string]string{
v1.LabelArchStable: "arm64",
},
},
}),
expectedEvictedCount: 1,
expectedEvictedPods: []string{"pod-0"},
namespaces: []string{"ns1"},
args: RemovePodsViolatingTopologySpreadConstraintArgs{},
},
}
for _, tc := range testCases {
@@ -1747,38 +1804,31 @@ func getLabelSelector(key string, values []string, operator metav1.LabelSelector
}
}
func getDefaultTopologyConstraints(maxSkew int32) []v1.TopologySpreadConstraint {
return []v1.TopologySpreadConstraint{
{
MaxSkew: maxSkew,
TopologyKey: "zone",
WhenUnsatisfiable: v1.DoNotSchedule,
LabelSelector: &metav1.LabelSelector{MatchLabels: map[string]string{"foo": "bar"}},
},
}
}
func getDefaultNodeTopologyConstraints(maxSkew int32) []v1.TopologySpreadConstraint {
return []v1.TopologySpreadConstraint{
{
MaxSkew: maxSkew,
TopologyKey: "node",
WhenUnsatisfiable: v1.DoNotSchedule,
LabelSelector: &metav1.LabelSelector{MatchLabels: map[string]string{"foo": "bar"}},
},
}
return getDefaultTopologyConstraints(maxSkew, func(constraint *v1.TopologySpreadConstraint) {
constraint.TopologyKey = "node"
})
}
func getDefaultTopologyConstraintsWithPodTemplateHashMatch(maxSkew int32) []v1.TopologySpreadConstraint {
return []v1.TopologySpreadConstraint{
{
MaxSkew: maxSkew,
TopologyKey: "zone",
WhenUnsatisfiable: v1.DoNotSchedule,
LabelSelector: &metav1.LabelSelector{MatchLabels: map[string]string{"foo": "bar"}},
MatchLabelKeys: []string{appsv1.DefaultDeploymentUniqueLabelKey},
},
return getDefaultTopologyConstraints(maxSkew, func(constraint *v1.TopologySpreadConstraint) {
constraint.MatchLabelKeys = []string{appsv1.DefaultDeploymentUniqueLabelKey}
})
}
func getDefaultTopologyConstraints(maxSkew int32, edits ...func(*v1.TopologySpreadConstraint)) []v1.TopologySpreadConstraint {
constraint := v1.TopologySpreadConstraint{
MaxSkew: maxSkew,
TopologyKey: "zone",
WhenUnsatisfiable: v1.DoNotSchedule,
LabelSelector: &metav1.LabelSelector{MatchLabels: map[string]string{"foo": "bar"}},
}
for _, edit := range edits {
edit(&constraint)
}
return []v1.TopologySpreadConstraint{constraint}
}
func TestCheckIdenticalConstraints(t *testing.T) {