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Use ToBeDeletedByClusterAutoscaler Taint to improve load balancing during machine terminations #1054

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Use ToBeDeletedByClusterAutoscaler Taint to improve load balancing during machine terminations #1054

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216a65f
Add ToBeDeletedByClusterAutoscaler taint after node drain
dergeberl Nov 25, 2025
92089bb
Fix error formatting and broken ref link
dergeberl Jan 12, 2026
1061ca6
Only check for taint key
dergeberl Jan 12, 2026
92c34b4
Fix typos; Fix wrong description.
dergeberl Apr 2, 2026
3eca7d4
Use AddOrUpdateTaint()
dergeberl Apr 2, 2026
930004a
Switch order
dergeberl Apr 2, 2026
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3 changes: 3 additions & 0 deletions pkg/util/provider/machinecontroller/machine.go
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Original file line number Diff line number Diff line change
Expand Up @@ -644,6 +644,9 @@ func (c *controller) triggerDeletionFlow(ctx context.Context, deleteMachineReque
case strings.Contains(machine.Status.LastOperation.Description, machineutils.DelVolumesAttachments):
return c.deleteNodeVolAttachments(ctx, deleteMachineRequest)

case strings.Contains(machine.Status.LastOperation.Description, machineutils.SetDeletionTaint):
return c.taintNode(ctx, deleteMachineRequest)

@elankath elankath Jul 15, 2026 •
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No need for separate stage. We should follow CA, where this taint is immediately set before draining the node. This can be moved to c.drainNode. No need for this explicit case and implementation can be made simpler. (This should not be done for c.drainPreservedNode or c.drainNodeForInPlace as those Nodes will come back)


case strings.Contains(machine.Status.LastOperation.Description, machineutils.InitiateVMDeletion):
return c.deleteVM(ctx, deleteMachineRequest)

Expand Down
326 changes: 319 additions & 7 deletions pkg/util/provider/machinecontroller/machine_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1949,7 +1949,7 @@ var _ = Describe("machine", func() {
},
},
expect: expect{
err: fmt.Errorf("Drain successful. %s", machineutils.InitiateVMDeletion),
err: fmt.Errorf("Drain successful. %s", machineutils.SetDeletionTaint),
retry: machineutils.ShortRetry,
nodeTerminationConditionIsSet: true,
machine: newMachine(
Expand All @@ -1969,7 +1969,7 @@ var _ = Describe("machine", func() {
LastUpdateTime: metav1.Now(),
},
LastOperation: v1alpha1.LastOperation{
Description: fmt.Sprintf("Drain successful. %s", machineutils.InitiateVMDeletion),
Description: fmt.Sprintf("Drain successful. %s", machineutils.SetDeletionTaint),
State: v1alpha1.MachineStateProcessing,
Type: v1alpha1.MachineOperationDelete,
LastUpdateTime: metav1.Now(),
Expand Down Expand Up @@ -2465,7 +2465,7 @@ var _ = Describe("machine", func() {
},
},
expect: expect{
err: fmt.Errorf("Drain successful. %s", machineutils.InitiateVMDeletion),
err: fmt.Errorf("Drain successful. %s", machineutils.SetDeletionTaint),
retry: machineutils.ShortRetry,
machine: newMachine(
&v1alpha1.MachineTemplateSpec{
Expand All @@ -2484,7 +2484,7 @@ var _ = Describe("machine", func() {
LastUpdateTime: metav1.Now(),
},
LastOperation: v1alpha1.LastOperation{
Description: fmt.Sprintf("Drain successful. %s", machineutils.InitiateVMDeletion),
Description: fmt.Sprintf("Drain successful. %s", machineutils.SetDeletionTaint),
State: v1alpha1.MachineStateProcessing,
Type: v1alpha1.MachineOperationDelete,
LastUpdateTime: metav1.Now(),
Expand Down Expand Up @@ -2567,7 +2567,7 @@ var _ = Describe("machine", func() {
},
},
expect: expect{
err: fmt.Errorf("Drain successful. %s", machineutils.InitiateVMDeletion),
err: fmt.Errorf("Drain successful. %s", machineutils.SetDeletionTaint),
retry: machineutils.ShortRetry,
machine: newMachine(
&v1alpha1.MachineTemplateSpec{
Expand All @@ -2586,7 +2586,7 @@ var _ = Describe("machine", func() {
LastUpdateTime: metav1.Now(),
},
LastOperation: v1alpha1.LastOperation{
Description: fmt.Sprintf("Drain successful. %s", machineutils.InitiateVMDeletion),
Description: fmt.Sprintf("Drain successful. %s", machineutils.SetDeletionTaint),
State: v1alpha1.MachineStateProcessing,
Type: v1alpha1.MachineOperationDelete,
LastUpdateTime: metav1.Now(),
Expand Down Expand Up @@ -3064,7 +3064,7 @@ var _ = Describe("machine", func() {
LastUpdateTime: metav1.Now(),
},
LastOperation: v1alpha1.LastOperation{
Description: fmt.Sprintf("Drain successful. %s", machineutils.InitiateVMDeletion),
Description: fmt.Sprintf("Node tainted. %s", machineutils.InitiateVMDeletion),
State: v1alpha1.MachineStateProcessing,
Type: v1alpha1.MachineOperationDelete,
LastUpdateTime: metav1.Now(),
Expand Down Expand Up @@ -3233,6 +3233,318 @@ var _ = Describe("machine", func() {
),
},
}),
Entry("Set ToBedeletedByClusterAutoscaler Taint", &data{
Comment thread
dergeberl marked this conversation as resolved.
setup: setup{
secrets: []*corev1.Secret{
{
ObjectMeta: *newObjectMeta(objMeta, 0),
},
},
machineClasses: []*v1alpha1.MachineClass{
{
ObjectMeta: *newObjectMeta(objMeta, 0),
SecretRef: newSecretReference(objMeta, 0),
},
},
machines: newMachines(
1,
&v1alpha1.MachineTemplateSpec{
ObjectMeta: *newObjectMeta(objMeta, 0),
Spec: v1alpha1.MachineSpec{
Class: v1alpha1.ClassSpec{
Kind: "MachineClass",
Name: "machine-0",
},
ProviderID: "fakeID",
},
},
&v1alpha1.MachineStatus{
CurrentStatus: v1alpha1.CurrentStatus{
Phase: v1alpha1.MachineTerminating,
LastUpdateTime: metav1.Now(),
},
LastOperation: v1alpha1.LastOperation{
Description: fmt.Sprintf("Drain successful. %s", machineutils.SetDeletionTaint),
State: v1alpha1.MachineStateProcessing,
Type: v1alpha1.MachineOperationDelete,
LastUpdateTime: metav1.Now(),
},
},
nil,
map[string]string{
machineutils.MachinePriority: "3",
},
map[string]string{
v1alpha1.NodeLabelKey: "fakeID-0",
},
true,
metav1.Now(),
),
nodes: []*corev1.Node{
{
ObjectMeta: metav1.ObjectMeta{
Name: "fakeID-0",
},
},
},
},
action: action{
machine: "machine-0",
fakeDriver: &driver.FakeDriver{
VMExists: true,
ProviderID: "fakeID-0",
NodeName: "fakeNode-0",
Err: nil,
},
},
expect: expect{
err: nil,
retry: machineutils.ShortRetry,
nodeDeleted: false,
machine: newMachine(
&v1alpha1.MachineTemplateSpec{
ObjectMeta: *newObjectMeta(objMeta, 0),
Spec: v1alpha1.MachineSpec{
Class: v1alpha1.ClassSpec{
Kind: "MachineClass",
Name: "machine-0",
},
ProviderID: "fakeID",
},
},
&v1alpha1.MachineStatus{
CurrentStatus: v1alpha1.CurrentStatus{
Phase: v1alpha1.MachineTerminating,
LastUpdateTime: metav1.Now(),
},
LastOperation: v1alpha1.LastOperation{
Description: fmt.Sprintf("Drain successful. %s", machineutils.SetDeletionTaint),
State: v1alpha1.MachineStateProcessing,
Type: v1alpha1.MachineOperationDelete,
LastUpdateTime: metav1.Now(),
},
},
nil,
map[string]string{
machineutils.MachinePriority: "3",
},
map[string]string{
v1alpha1.NodeLabelKey: "fakeID-0",
},
true,
metav1.Now(),
),
},
}),
Entry("Continue if ToBedeletedByClusterAutoscaler Taint is set", &data{
setup: setup{
secrets: []*corev1.Secret{
{
ObjectMeta: *newObjectMeta(objMeta, 0),
},
},
machineClasses: []*v1alpha1.MachineClass{
{
ObjectMeta: *newObjectMeta(objMeta, 0),
SecretRef: newSecretReference(objMeta, 0),
},
},
machines: newMachines(
1,
&v1alpha1.MachineTemplateSpec{
ObjectMeta: *newObjectMeta(objMeta, 0),
Spec: v1alpha1.MachineSpec{
Class: v1alpha1.ClassSpec{
Kind: "MachineClass",
Name: "machine-0",
},
ProviderID: "fakeID",
},
},
&v1alpha1.MachineStatus{
CurrentStatus: v1alpha1.CurrentStatus{
Phase: v1alpha1.MachineTerminating,
LastUpdateTime: metav1.Now(),
},
LastOperation: v1alpha1.LastOperation{
Description: fmt.Sprintf("Drain successful. %s", machineutils.SetDeletionTaint),
State: v1alpha1.MachineStateProcessing,
Type: v1alpha1.MachineOperationDelete,
LastUpdateTime: metav1.Now(),
},
},
nil,
map[string]string{
machineutils.MachinePriority: "3",
},
map[string]string{
v1alpha1.NodeLabelKey: "fakeID-0",
},
true,
metav1.Now(),
),
nodes: []*corev1.Node{
{
ObjectMeta: metav1.ObjectMeta{
Name: "fakeID-0",
},
Spec: corev1.NodeSpec{
Taints: []corev1.Taint{
{
Key: machineutils.TaintToBeDeleted,
Value: "gardener-machine-controller-manager",
Effect: corev1.TaintEffectPreferNoSchedule,
},
},
},
},
},
},
action: action{
machine: "machine-0",
fakeDriver: &driver.FakeDriver{
VMExists: true,
ProviderID: "fakeID-0",
NodeName: "fakeNode-0",
Err: nil,
},
},
expect: expect{
err: nil,
retry: machineutils.ShortRetry,
nodeDeleted: false,
machine: newMachine(
&v1alpha1.MachineTemplateSpec{
ObjectMeta: *newObjectMeta(objMeta, 0),
Spec: v1alpha1.MachineSpec{
Class: v1alpha1.ClassSpec{
Kind: "MachineClass",
Name: "machine-0",
},
ProviderID: "fakeID",
},
},
&v1alpha1.MachineStatus{
CurrentStatus: v1alpha1.CurrentStatus{
Phase: v1alpha1.MachineTerminating,
LastUpdateTime: metav1.Now(),
},
LastOperation: v1alpha1.LastOperation{
Description: fmt.Sprintf("Node tainted. %s", machineutils.InitiateVMDeletion),
State: v1alpha1.MachineStateProcessing,
Type: v1alpha1.MachineOperationDelete,
LastUpdateTime: metav1.Now(),
},
},
nil,
map[string]string{
machineutils.MachinePriority: "3",
},
map[string]string{
v1alpha1.NodeLabelKey: "fakeID-0",
},
true,
metav1.Now(),
),
},
}),
Entry("Skip ToBedeletedByClusterAutoscaler Taint if node does not exist", &data{
setup: setup{
secrets: []*corev1.Secret{
{
ObjectMeta: *newObjectMeta(objMeta, 0),
},
},
machineClasses: []*v1alpha1.MachineClass{
{
ObjectMeta: *newObjectMeta(objMeta, 0),
SecretRef: newSecretReference(objMeta, 0),
},
},
machines: newMachines(
1,
&v1alpha1.MachineTemplateSpec{
ObjectMeta: *newObjectMeta(objMeta, 0),
Spec: v1alpha1.MachineSpec{
Class: v1alpha1.ClassSpec{
Kind: "MachineClass",
Name: "machine-0",
},
ProviderID: "fakeID",
},
},
&v1alpha1.MachineStatus{
CurrentStatus: v1alpha1.CurrentStatus{
Phase: v1alpha1.MachineTerminating,
LastUpdateTime: metav1.Now(),
},
LastOperation: v1alpha1.LastOperation{
Description: fmt.Sprintf("Drain successful. %s", machineutils.SetDeletionTaint),
State: v1alpha1.MachineStateProcessing,
Type: v1alpha1.MachineOperationDelete,
LastUpdateTime: metav1.Now(),
},
},
nil,
map[string]string{
machineutils.MachinePriority: "3",
},
map[string]string{
v1alpha1.NodeLabelKey: "fakeID-0",
},
true,
metav1.Now(),
),
nodes: []*corev1.Node{},
},
action: action{
machine: "machine-0",
fakeDriver: &driver.FakeDriver{
VMExists: true,
ProviderID: "fakeID-0",
NodeName: "fakeNode-0",
Err: nil,
},
},
expect: expect{
err: nil,
retry: machineutils.ShortRetry,
nodeDeleted: false,
machine: newMachine(
&v1alpha1.MachineTemplateSpec{
ObjectMeta: *newObjectMeta(objMeta, 0),
Spec: v1alpha1.MachineSpec{
Class: v1alpha1.ClassSpec{
Kind: "MachineClass",
Name: "machine-0",
},
ProviderID: "fakeID",
},
},
&v1alpha1.MachineStatus{
CurrentStatus: v1alpha1.CurrentStatus{
Phase: v1alpha1.MachineTerminating,
LastUpdateTime: metav1.Now(),
},
LastOperation: v1alpha1.LastOperation{
Description: fmt.Sprintf("Node does not exist. %s", machineutils.InitiateVMDeletion),
State: v1alpha1.MachineStateProcessing,
Type: v1alpha1.MachineOperationDelete,
LastUpdateTime: metav1.Now(),
},
},
nil,
map[string]string{
machineutils.MachinePriority: "3",
},
map[string]string{
v1alpha1.NodeLabelKey: "fakeID-0",
},
true,
metav1.Now(),
),
},
}),
Entry("Delete node object successfully", &data{
setup: setup{
secrets: []*corev1.Secret{
Expand Down
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