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[release-4.22] OCPBUGS-84850: Custom pool booting must handle matchExpressions in nodeSelector #5909

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Merged
openshift-merge-bot merged 1 commit into from
May 1, 2026
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[release-4.22] OCPBUGS-84850: Custom pool booting must handle matchExpressions in nodeSelector #5909

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40 changes: 36 additions & 4 deletions pkg/controller/node/node_controller.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1667,20 +1667,52 @@ func (ctrl *Controller) applyCustomPoolLabels(node *corev1.Node, poolName string
}

// Extract labels from the pool's node selector
if pool.Spec.NodeSelector == nil || pool.Spec.NodeSelector.MatchLabels == nil {
klog.V(4).Infof("MachineConfigPool %s has no node selector labels", poolName)
if pool.Spec.NodeSelector == nil {
klog.Infof("MachineConfigPool %s has no node selector", poolName)
return nil
}

labelsToApply := pool.Spec.NodeSelector.MatchLabels
labelsToApply := map[string]string{}

maps.Copy(labelsToApply, pool.Spec.NodeSelector.MatchLabels)

// For matchExpressions, derive a label only when the value is unambiguous:
// - In with a single value, key=value
// - Exists, key=""
// On a conflict with an existing key, priortize the value from MatchLabels
for _, expr := range pool.Spec.NodeSelector.MatchExpressions {
switch expr.Operator {
case metav1.LabelSelectorOpIn:
if len(expr.Values) == 1 {
if _, alreadySet := labelsToApply[expr.Key]; !alreadySet {
labelsToApply[expr.Key] = expr.Values[0]
}
} else {
klog.Infof("MachineConfigPool %s matchExpression key %q has multiple values, skipping", poolName, expr.Key)
}
case metav1.LabelSelectorOpExists:
if _, alreadySet := labelsToApply[expr.Key]; !alreadySet {
labelsToApply[expr.Key] = ""
}
}
}

if len(labelsToApply) == 0 {
klog.Infof("MachineConfigPool %s has no applicable node selector labels", poolName)
return nil
}

klog.Infof("Node %s was booted into custom pool %s; applying node selector labels: %v", poolName, node.Name, labelsToApply)
klog.Infof("Node %s was booted into custom pool %s; applying node selector labels: %v", node.Name, poolName, labelsToApply)

// Apply the labels to the node and add annotation indicating custom pool labels were applied
_, err = internal.UpdateNodeRetry(ctrl.kubeClient.CoreV1().Nodes(), ctrl.nodeLister, node.Name, func(node *corev1.Node) {
// Highly unlikely, but check to be safe
if node.Labels == nil {
node.Labels = map[string]string{}
}
if node.Annotations == nil {
node.Annotations = map[string]string{}
}
// Apply the custom pool labels
maps.Copy(node.Labels, labelsToApply)

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193 changes: 193 additions & 0 deletions pkg/controller/node/node_controller_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2238,6 +2238,199 @@ func TestFilterCustomPoolBootedNodes(t *testing.T) {
}
}

func TestApplyCustomPoolLabels(t *testing.T) {
t.Parallel()

baseNode := func(name string) *corev1.Node {
return &corev1.Node{
ObjectMeta: metav1.ObjectMeta{
Name: name,
Labels: map[string]string{"node-role.kubernetes.io/worker": ""},
Annotations: map[string]string{},
},
}
}

pool := func(name string, sel *metav1.LabelSelector) *mcfgv1.MachineConfigPool {
return helpers.NewMachineConfigPoolBuilder(name).WithNodeSelector(sel).MachineConfigPool()
}

tests := []struct {
name string
pool *mcfgv1.MachineConfigPool
poolName string
expectErr bool
expectedLabels map[string]string
expectAnnot bool // whether CustomPoolLabelsAppliedAnnotationKey should be set
}{
{
name: "matchLabels only",
poolName: "infra",
pool: pool("infra", &metav1.LabelSelector{
MatchLabels: map[string]string{"node-role.kubernetes.io/infra": ""},
}),
expectedLabels: map[string]string{
"node-role.kubernetes.io/worker": "",
"node-role.kubernetes.io/infra": "",
},
expectAnnot: true,
},
{
name: "matchExpressions In single value",
poolName: "infra",
pool: pool("infra", &metav1.LabelSelector{
MatchExpressions: []metav1.LabelSelectorRequirement{
{Key: "node-role.kubernetes.io/infra", Operator: metav1.LabelSelectorOpIn, Values: []string{""}},
},
}),
expectedLabels: map[string]string{
"node-role.kubernetes.io/worker": "",
"node-role.kubernetes.io/infra": "",
},
expectAnnot: true,
},
{
name: "matchExpressions In multiple values skipped",
poolName: "infra",
pool: pool("infra", &metav1.LabelSelector{
MatchExpressions: []metav1.LabelSelectorRequirement{
{Key: "zone", Operator: metav1.LabelSelectorOpIn, Values: []string{"us-east-1a", "us-east-1b"}},
},
}),
// no new labels — ambiguous In is skipped, nothing to apply
expectedLabels: map[string]string{
"node-role.kubernetes.io/worker": "",
},
expectAnnot: false,
},
{
name: "matchExpressions Exists",
poolName: "infra",
pool: pool("infra", &metav1.LabelSelector{
MatchExpressions: []metav1.LabelSelectorRequirement{
{Key: "node-role.kubernetes.io/infra", Operator: metav1.LabelSelectorOpExists},
},
}),
expectedLabels: map[string]string{
"node-role.kubernetes.io/worker": "",
"node-role.kubernetes.io/infra": "",
},
expectAnnot: true,
},
{
name: "matchExpressions NotIn and DoesNotExist are skipped",
poolName: "infra",
pool: pool("infra", &metav1.LabelSelector{
MatchExpressions: []metav1.LabelSelectorRequirement{
{Key: "bad-key", Operator: metav1.LabelSelectorOpNotIn, Values: []string{"val"}},
{Key: "another-key", Operator: metav1.LabelSelectorOpDoesNotExist},
},
}),
expectedLabels: map[string]string{
"node-role.kubernetes.io/worker": "",
},
expectAnnot: false,
},
{
name: "matchLabels and matchExpressions both applied",
poolName: "infra",
pool: pool("infra", &metav1.LabelSelector{
MatchLabels: map[string]string{"node-role.kubernetes.io/infra": ""},
MatchExpressions: []metav1.LabelSelectorRequirement{
{Key: "topology.kubernetes.io/zone", Operator: metav1.LabelSelectorOpIn, Values: []string{"us-east-1a"}},
},
}),
expectedLabels: map[string]string{
"node-role.kubernetes.io/worker": "",
"node-role.kubernetes.io/infra": "",
"topology.kubernetes.io/zone": "us-east-1a",
},
expectAnnot: true,
},
{
name: "matchLabels wins over Exists for same key",
poolName: "infra",
pool: pool("infra", &metav1.LabelSelector{
MatchLabels: map[string]string{"node-role.kubernetes.io/infra": "specific-value"},
MatchExpressions: []metav1.LabelSelectorRequirement{
{Key: "node-role.kubernetes.io/infra", Operator: metav1.LabelSelectorOpExists},
},
}),
expectedLabels: map[string]string{
"node-role.kubernetes.io/worker": "",
"node-role.kubernetes.io/infra": "specific-value",
},
expectAnnot: true,
},
{
name: "matchLabels wins over In for same key",
poolName: "infra",
pool: pool("infra", &metav1.LabelSelector{
MatchLabels: map[string]string{"node-role.kubernetes.io/infra": "from-matchlabels"},
MatchExpressions: []metav1.LabelSelectorRequirement{
{Key: "node-role.kubernetes.io/infra", Operator: metav1.LabelSelectorOpIn, Values: []string{"from-expression"}},
},
}),
expectedLabels: map[string]string{
"node-role.kubernetes.io/worker": "",
"node-role.kubernetes.io/infra": "from-matchlabels",
},
expectAnnot: true,
},
{
name: "nil node selector returns without error",
poolName: "infra",
pool: pool("infra", nil),
expectedLabels: map[string]string{
"node-role.kubernetes.io/worker": "",
},
expectAnnot: false,
},
{
name: "pool not found returns error",
poolName: "nonexistent",
pool: nil,
expectErr: true,
},
}

for _, test := range tests {
test := test
t.Run(test.name, func(t *testing.T) {
t.Parallel()

f := newFixture(t)
node := baseNode("test-node")

f.nodeLister = append(f.nodeLister, node)
f.kubeobjects = append(f.kubeobjects, node)

if test.pool != nil {
f.mcpLister = append(f.mcpLister, test.pool)
f.objects = append(f.objects, test.pool)
}

c := f.newController()

err := c.applyCustomPoolLabels(node, test.poolName)

if test.expectErr {
require.Error(t, err)
return
}
require.NoError(t, err)

updated, getErr := f.kubeclient.CoreV1().Nodes().Get(context.TODO(), node.Name, metav1.GetOptions{})
require.NoError(t, getErr)

assert.Equal(t, test.expectedLabels, updated.Labels)

_, hasAnnot := updated.Annotations[daemonconsts.CustomPoolLabelsAppliedAnnotationKey]
assert.Equal(t, test.expectAnnot, hasAnnot, "CustomPoolLabelsAppliedAnnotationKey presence mismatch")
})
}
}

// adds annotation to the node
func addNodeAnnotations(node *corev1.Node, annotations map[string]string) {
if node.Annotations == nil {
Expand Down