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chore: Use self-affinity to ensure all pods schedule #1938

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Jan 28, 2025
Merged

chore: Use self-affinity to ensure all pods schedule #1938

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47 changes: 39 additions & 8 deletions pkg/controllers/provisioning/scheduling/scheduling_benchmark_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -90,6 +90,12 @@ func BenchmarkScheduling2000(b *testing.B) {
func BenchmarkScheduling5000(b *testing.B) {
benchmarkScheduler(b, 400, 5000)
}
func BenchmarkScheduling10000(b *testing.B) {
benchmarkScheduler(b, 400, 10000)
}
func BenchmarkScheduling20000(b *testing.B) {
benchmarkScheduler(b, 400, 20000)
}
Comment on lines +93 to +98
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Nice!


// TestSchedulingProfile is used to gather profiling metrics, benchmarking is primarily done with standard
// Go benchmark functions
Expand All @@ -114,7 +120,7 @@ func TestSchedulingProfile(t *testing.T) {
totalNodes := 0
var totalTime time.Duration
for _, instanceCount := range []int{400} {
for _, podCount := range []int{10, 100, 500, 1000, 1500, 2000, 5000} {
for _, podCount := range []int{1, 50, 100, 500, 1000, 1500, 2000, 5000, 10000, 20000} {
start := time.Now()
res := testing.Benchmark(func(b *testing.B) { benchmarkScheduler(b, instanceCount, podCount) })
totalTime += time.Since(start) / time.Duration(res.N)
Expand All @@ -128,6 +134,7 @@ func TestSchedulingProfile(t *testing.T) {
tw.Flush()
}

// nolint:gocyclo
func benchmarkScheduler(b *testing.B, instanceCount, podCount int) {
// disable logging
ctx = ctrl.IntoContext(context.Background(), operatorlogging.NopLogger)
Expand All @@ -149,8 +156,8 @@ func benchmarkScheduler(b *testing.B, instanceCount, podCount int) {
pods := makeDiversePods(podCount)
clock := &clock.RealClock{}
cluster = state.NewCluster(clock, client, cloudProvider)
domains := map[string]sets.Set[string]{}
topology, err := scheduling.NewTopology(ctx, client, cluster, domains, pods)

topology, err := scheduling.NewTopology(ctx, client, cluster, getDomains(instanceTypes), pods)
if err != nil {
b.Fatalf("creating topology, %s", err)
}
Expand All @@ -167,8 +174,10 @@ func benchmarkScheduler(b *testing.B, instanceCount, podCount int) {
nodesInRound1 := 0
for i := 0; i < b.N; i++ {
results := scheduler.Solve(ctx, pods)
if len(results.PodErrors) > 0 {
b.Fatalf("expected all pods to schedule, got %d pods that didn't", len(results.PodErrors))
}
if i == 0 {

minPods := math.MaxInt64
maxPods := 0
var podCounts []int
Expand Down Expand Up @@ -212,13 +221,30 @@ func benchmarkScheduler(b *testing.B, instanceCount, podCount int) {
}
}

func getDomains(instanceTypes []*cloudprovider.InstanceType) map[string]sets.Set[string] {
domains := map[string]sets.Set[string]{}
for _, it := range instanceTypes {
for key, requirement := range it.Requirements {
// This code used to execute a Union between domains[key] and requirement.Values().
// The downside of this is that Union is immutable and takes a copy of the set it is executed upon.
// This resulted in a lot of memory pressure on the heap and poor performance
// https://github.com/aws/karpenter/issues/3565
if domains[key] == nil {
domains[key] = sets.New(requirement.Values()...)
} else {
domains[key].Insert(requirement.Values()...)
}
}
}
return domains
}

func makeDiversePods(count int) []*corev1.Pod {
var pods []*corev1.Pod
numTypes := 6
numTypes := 5
pods = append(pods, makeGenericPods(count/numTypes)...)
pods = append(pods, makeTopologySpreadPods(count/numTypes, corev1.LabelTopologyZone)...)
pods = append(pods, makeTopologySpreadPods(count/numTypes, corev1.LabelHostname)...)
pods = append(pods, makePodAffinityPods(count/numTypes, corev1.LabelHostname)...)
pods = append(pods, makePodAffinityPods(count/numTypes, corev1.LabelTopologyZone)...)
pods = append(pods, makePodAntiAffinityPods(count/numTypes, corev1.LabelHostname)...)

Expand Down Expand Up @@ -259,15 +285,20 @@ func makePodAntiAffinityPods(count int, key string) []*corev1.Pod {
func makePodAffinityPods(count int, key string) []*corev1.Pod {
var pods []*corev1.Pod
for i := 0; i < count; i++ {
// We use self-affinity here because using affinity that relies on other pod
// domains doens't guarantee that all pods can schedule. In the case where you are not
// using self-affinity and the domain doesn't exist, scheduling will fail for all pods with
// affinities against this domain
labels := randomAffinityLabels()
pods = append(pods, test.Pod(
test.PodOptions{
ObjectMeta: metav1.ObjectMeta{
Labels: randomAffinityLabels(),
Labels: labels,
UID: uuid.NewUUID(),
},
PodRequirements: []corev1.PodAffinityTerm{
{
LabelSelector: &metav1.LabelSelector{MatchLabels: randomAffinityLabels()},
LabelSelector: &metav1.LabelSelector{MatchLabels: labels},
TopologyKey: key,
},
},
Expand Down