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CNTRLPLANE-3040: add regression tests for CAS pause/unpause replica clamping #8262

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openshift-merge-bot merged 1 commit into from
May 26, 2026
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CNTRLPLANE-3040: add regression tests for CAS pause/unpause replica clamping #8262

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285 changes: 285 additions & 0 deletions hypershift-operator/controllers/nodepool/capi_test.go
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jparrill marked this conversation as resolved.
Original file line number Diff line number Diff line change
Expand Up @@ -2943,6 +2943,291 @@ func TestPropagateLabelsAndTaintsToMachines(t *testing.T) {
}
}

// TestPauseUnpauseCycle is a regression test for the interaction between pausing
// NodePools and the Cluster Autoscaler (OCPBUGS-78152 / CNTRLPLANE-3040).
//
// It verifies that:
// - When a MachineDeployment/MachineSet is paused, the pause annotation is set
// - When reconcileMachineDeployment/reconcileMachineSet runs after unpause, the
// pause annotation is removed and autoscaler annotations are preserved
// - setMachineDeploymentReplicas clamps replicas within [min, max] bounds regardless
// of external modifications (e.g. CAS decrementing replicas while paused)

@enxebre enxebre May 20, 2026

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isn't all this really effectively the same than adding a few test cases for TestSetMachineDeploymentReplicas and TestSetMachineSetReplicas?

@jparrill jparrill May 20, 2026 •
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Fair point — the clamping logic itself is the same. The difference is that TestPauseUnpauseCycle exercises the full reconcile flow end-to-end:

Pause annotation set on NodePool
        │
        ▼
External replica modification (CAS decrements while paused)
        │
        ▼
reconcileMachineDeployment / reconcileMachineSet
        │
        ▼
Pause annotation removed
        │
        ▼
Replicas clamped back to [min, max]

Adding cases to TestSetMachineDeploymentReplicas/TestSetMachineSetReplicas would cover the clamping in isolation, but wouldn't validate that all the pieces work together through the reconcile cycle. I think both are worth keeping — unit cases for the function, integration-style test for the flow.

func TestPauseUnpauseCycle(t *testing.T) {
t.Parallel()
testCases := []struct {
name string
upgradeType hyperv1.UpgradeType
platformType hyperv1.PlatformType
initialReplicas int32
autoscalingMin int32
autoscalingMax int32
replicasAtUnpause int32
expectedReplicas int32
}{
{
name: "When a paused MachineDeployment is unpaused it should remove the pause annotation and preserve replicas",
upgradeType: hyperv1.UpgradeTypeReplace,
platformType: hyperv1.AWSPlatform,
initialReplicas: 4,
autoscalingMin: 1,
autoscalingMax: 4,
replicasAtUnpause: 4,
expectedReplicas: 4,
},
{
name: "When a paused MachineDeployment has replicas decremented to min it should keep replicas at min on unpause",
upgradeType: hyperv1.UpgradeTypeReplace,
platformType: hyperv1.AWSPlatform,
initialReplicas: 4,
autoscalingMin: 1,
autoscalingMax: 4,
replicasAtUnpause: 1,
expectedReplicas: 1,
},
{
name: "When a paused MachineDeployment has replicas decremented below min it should clamp to min on unpause",
upgradeType: hyperv1.UpgradeTypeReplace,
platformType: hyperv1.AWSPlatform,
initialReplicas: 4,
autoscalingMin: 2,
autoscalingMax: 4,
replicasAtUnpause: 1,
expectedReplicas: 2,
},
{
name: "When a paused MachineDeployment has replicas incremented above max it should clamp to max on unpause",
upgradeType: hyperv1.UpgradeTypeReplace,
platformType: hyperv1.AWSPlatform,
initialReplicas: 4,
autoscalingMin: 1,
autoscalingMax: 4,
replicasAtUnpause: 6,
expectedReplicas: 4,
},
{
name: "When a paused MachineDeployment on AWS with min 0 it should allow scale to zero on unpause",
upgradeType: hyperv1.UpgradeTypeReplace,
platformType: hyperv1.AWSPlatform,
initialReplicas: 4,
autoscalingMin: 0,
autoscalingMax: 4,
replicasAtUnpause: 0,
expectedReplicas: 0,
},
{
name: "When a paused MachineDeployment on non-AWS with min 0 it should clamp to effective min 1 on unpause",
upgradeType: hyperv1.UpgradeTypeReplace,
platformType: hyperv1.KubevirtPlatform,
initialReplicas: 4,
autoscalingMin: 0,
autoscalingMax: 4,
replicasAtUnpause: 0,
expectedReplicas: 1,
},
{
name: "When a paused MachineSet is unpaused it should remove the pause annotation and preserve replicas",
upgradeType: hyperv1.UpgradeTypeInPlace,
platformType: hyperv1.AWSPlatform,
initialReplicas: 4,
autoscalingMin: 1,
autoscalingMax: 4,
replicasAtUnpause: 4,
expectedReplicas: 4,
},
{
name: "When a paused MachineSet has replicas decremented below min it should clamp to min on unpause",
upgradeType: hyperv1.UpgradeTypeInPlace,
platformType: hyperv1.AWSPlatform,
initialReplicas: 4,
autoscalingMin: 2,
autoscalingMax: 4,
replicasAtUnpause: 1,
expectedReplicas: 2,
},
{
name: "When a paused MachineSet has replicas incremented above max it should clamp to max on unpause",
upgradeType: hyperv1.UpgradeTypeInPlace,
platformType: hyperv1.AWSPlatform,
initialReplicas: 4,
autoscalingMin: 1,
autoscalingMax: 4,
replicasAtUnpause: 6,
expectedReplicas: 4,
},
{
name: "When a paused MachineSet on AWS with min 0 it should allow scale to zero on unpause",
upgradeType: hyperv1.UpgradeTypeInPlace,
platformType: hyperv1.AWSPlatform,
initialReplicas: 4,
autoscalingMin: 0,
autoscalingMax: 4,
replicasAtUnpause: 0,
expectedReplicas: 0,
},
{
name: "When a paused MachineSet on non-AWS with min 0 it should clamp to effective min 1 on unpause",
upgradeType: hyperv1.UpgradeTypeInPlace,
platformType: hyperv1.KubevirtPlatform,
initialReplicas: 4,
autoscalingMin: 0,
autoscalingMax: 4,
replicasAtUnpause: 0,
expectedReplicas: 1,
},
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}

for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
g := NewWithT(t)

nodePool := &hyperv1.NodePool{
ObjectMeta: metav1.ObjectMeta{
Name: "test-nodepool",
Namespace: "test-namespace",
},
Spec: hyperv1.NodePoolSpec{
ClusterName: "test-cluster",
AutoScaling: &hyperv1.NodePoolAutoScaling{
Min: ptr.To[int32](tc.autoscalingMin),
Max: tc.autoscalingMax,
},
Management: hyperv1.NodePoolManagement{
UpgradeType: tc.upgradeType,
Replace: &hyperv1.ReplaceUpgrade{
Strategy: hyperv1.UpgradeStrategyRollingUpdate,
RollingUpdate: &hyperv1.RollingUpdate{
MaxUnavailable: ptr.To(intstr.FromInt(0)),
MaxSurge: ptr.To(intstr.FromInt(1)),
},
},
},
Platform: hyperv1.NodePoolPlatform{
Type: tc.platformType,
},
},
}
if tc.platformType == hyperv1.AWSPlatform {
nodePool.Spec.Platform.AWS = &hyperv1.AWSNodePoolPlatform{AMI: "test-ami"}
}

hostedCluster := &hyperv1.HostedCluster{
ObjectMeta: metav1.ObjectMeta{
Name: "test-cluster",
Namespace: "test-namespace",
},
Spec: hyperv1.HostedClusterSpec{
Platform: hyperv1.PlatformSpec{
Type: tc.platformType,
},
},
}
if tc.platformType == hyperv1.AWSPlatform {
hostedCluster.Spec.Platform.AWS = &hyperv1.AWSPlatformSpec{}
}

controlPlaneNamespace := "test-cp-namespace"
c := fake.NewClientBuilder().WithScheme(api.Scheme).Build()
capiObj := &CAPI{
Token: &Token{
ConfigGenerator: &ConfigGenerator{
nodePool: nodePool,
hostedCluster: hostedCluster,
controlplaneNamespace: controlPlaneNamespace,
Client: c,
rolloutConfig: &rolloutConfig{
releaseImage: &releaseinfo.ReleaseImage{
ImageStream: &imageapi.ImageStream{
ObjectMeta: metav1.ObjectMeta{
Name: "target-version",
},
},
},
},
},
cpoCapabilities: &CPOCapabilities{},
CreateOrUpdateProvider: upsert.New(false),
},
capiClusterName: "test-cluster",
}

// Create MachineDeployment and MachineSet with initial replicas and autoscaler annotations.
md := capiObj.machineDeployment()
md.Spec.Replicas = ptr.To[int32](tc.initialReplicas)
md.Annotations = map[string]string{
autoscalerMinAnnotation: fmt.Sprintf("%d", tc.autoscalingMin),
autoscalerMaxAnnotation: fmt.Sprintf("%d", tc.autoscalingMax),
}
g.Expect(c.Create(t.Context(), md)).To(Succeed())

ms := capiObj.machineSet()
ms.Spec.Replicas = ptr.To[int32](tc.initialReplicas)
ms.Annotations = map[string]string{
autoscalerMinAnnotation: fmt.Sprintf("%d", tc.autoscalingMin),
autoscalerMaxAnnotation: fmt.Sprintf("%d", tc.autoscalingMax),
}
g.Expect(c.Create(t.Context(), ms)).To(Succeed())

// Step 1: Pause.
g.Expect(capiObj.Pause(t.Context())).To(Succeed())

g.Expect(c.Get(t.Context(), client.ObjectKeyFromObject(md), md)).To(Succeed())
g.Expect(md.Annotations).To(HaveKeyWithValue(capiv1.PausedAnnotation, "true"))

g.Expect(c.Get(t.Context(), client.ObjectKeyFromObject(ms), ms)).To(Succeed())
g.Expect(ms.Annotations).To(HaveKeyWithValue(capiv1.PausedAnnotation, "true"))

// Step 2: Simulate replica drift while paused (e.g. CAS decrementing via Scale subresource).
if tc.upgradeType == hyperv1.UpgradeTypeReplace {
md.Spec.Replicas = ptr.To[int32](tc.replicasAtUnpause)
g.Expect(c.Update(t.Context(), md)).To(Succeed())
} else {
ms.Spec.Replicas = ptr.To[int32](tc.replicasAtUnpause)
g.Expect(c.Update(t.Context(), ms)).To(Succeed())
}

// Step 3: Unpause by calling the reconcile functions (simulates the NodePool controller
// reconciling after PausedUntil expires, which calls capi.Reconcile()).
log := ctrl.LoggerFrom(t.Context())
template := &capiaws.AWSMachineTemplate{
ObjectMeta: metav1.ObjectMeta{
Name: "test-template",
Namespace: controlPlaneNamespace,
},
}

// For non-AWS platforms, effectiveMin is clamped to 1 when autoscalingMin is 0.
expectedMinAnnotation := tc.autoscalingMin
if tc.autoscalingMin == 0 && tc.platformType != hyperv1.AWSPlatform {
expectedMinAnnotation = 1
}

if tc.upgradeType == hyperv1.UpgradeTypeReplace {
g.Expect(c.Get(t.Context(), client.ObjectKeyFromObject(md), md)).To(Succeed())
g.Expect(capiObj.reconcileMachineDeployment(t.Context(), log, md, template)).To(Succeed())

// Verify pause annotation removed.
g.Expect(md.Annotations).NotTo(HaveKey(capiv1.PausedAnnotation))
// Verify replicas clamped within autoscaler bounds.
g.Expect(*md.Spec.Replicas).To(Equal(tc.expectedReplicas))
// Verify autoscaler annotations preserved.
g.Expect(md.Annotations).To(HaveKeyWithValue(autoscalerMinAnnotation, fmt.Sprintf("%d", expectedMinAnnotation)))
g.Expect(md.Annotations).To(HaveKeyWithValue(autoscalerMaxAnnotation, fmt.Sprintf("%d", tc.autoscalingMax)))
} else {
g.Expect(c.Get(t.Context(), client.ObjectKeyFromObject(ms), ms)).To(Succeed())
g.Expect(capiObj.reconcileMachineSet(t.Context(), ms, template)).To(Succeed())

// Verify pause annotation removed.
g.Expect(ms.Annotations).NotTo(HaveKey(capiv1.PausedAnnotation))
// Verify replicas clamped within autoscaler bounds.
g.Expect(*ms.Spec.Replicas).To(Equal(tc.expectedReplicas))
// Verify autoscaler annotations preserved.
g.Expect(ms.Annotations).To(HaveKeyWithValue(autoscalerMinAnnotation, fmt.Sprintf("%d", expectedMinAnnotation)))
g.Expect(ms.Annotations).To(HaveKeyWithValue(autoscalerMaxAnnotation, fmt.Sprintf("%d", tc.autoscalingMax)))
}
})
}
}

func TestNewCAPI(t *testing.T) {
t.Parallel()
testCases := []struct {
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