fix: stop using remove node label

balancer/main.go

@@ -26,7 +26,7 @@ import (
 	balancerclientset "k8s.io/autoscaler/balancer/pkg/client/clientset/versioned"
 	balancerinformers "k8s.io/autoscaler/balancer/pkg/client/informers/externalversions"
 	"k8s.io/autoscaler/balancer/pkg/controller"
-	cacheddiscovery "k8s.io/client-go/discovery/cached"
+	cacheddiscovery "k8s.io/client-go/discovery/cached/memory"
 	"k8s.io/client-go/dynamic"
 	kubeinformers "k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes"

cluster-autoscaler/cloudprovider/clusterapi/README.md

@@ -326,6 +326,8 @@ metadata:
     cluster.x-k8s.io/autoscaling-options-scaledownunreadytime: "20m0s"
     # overrides --max-node-provision-time global value for that specific MachineDeployment
     cluster.x-k8s.io/autoscaling-options-maxnodeprovisiontime: "20m0s"
+    # overrides --max-node-startup-time global value for that specific MachineDeployment
+    cluster.x-k8s.io/autoscaling-options-maxnodestartuptime: "20m0s"
 ```
 
 #### CPU Architecture awareness for single-arch clusters 

cluster-autoscaler/cloudprovider/clusterapi/clusterapi_nodegroup.go

@@ -470,6 +470,9 @@ func (ng *nodegroup) GetOptions(defaults config.NodeGroupAutoscalingOptions) (*c
 	if opt, ok := getDurationOption(options, ng.Id(), config.DefaultMaxNodeProvisionTimeKey); ok {
 		defaults.MaxNodeProvisionTime = opt
 	}
+	if opt, ok := getDurationOption(options, ng.Id(), config.DefaultMaxNodeStartupTimeKey); ok {
+		defaults.MaxNodeStartupTime = opt
+	}
 
 	return &defaults, nil
 }

cluster-autoscaler/cloudprovider/clusterapi/clusterapi_nodegroup_test.go

@@ -1768,6 +1768,7 @@ func TestNodeGroupGetOptions(t *testing.T) {
 		ScaleDownUnneededTime:            time.Second,
 		ScaleDownUnreadyTime:             time.Minute,
 		MaxNodeProvisionTime:             15 * time.Minute,
+		MaxNodeStartupTime:               35 * time.Minute,
 	}
 
 	cases := []struct {
@@ -1788,13 +1789,15 @@ func TestNodeGroupGetOptions(t *testing.T) {
 				config.DefaultScaleDownUnneededTimeKey:            "1h",
 				config.DefaultScaleDownUnreadyTimeKey:             "30m",
 				config.DefaultMaxNodeProvisionTimeKey:             "60m",
+				config.DefaultMaxNodeStartupTimeKey:               "35m",
 			},
 			expected: &config.NodeGroupAutoscalingOptions{
 				ScaleDownGpuUtilizationThreshold: 0.6,
 				ScaleDownUtilizationThreshold:    0.7,
 				ScaleDownUnneededTime:            time.Hour,
 				ScaleDownUnreadyTime:             30 * time.Minute,
 				MaxNodeProvisionTime:             60 * time.Minute,
+				MaxNodeStartupTime:               35 * time.Minute,
 			},
 		},
 		{
@@ -1809,6 +1812,7 @@ func TestNodeGroupGetOptions(t *testing.T) {
 				ScaleDownUnneededTime:            time.Minute,
 				ScaleDownUnreadyTime:             defaultOptions.ScaleDownUnreadyTime,
 				MaxNodeProvisionTime:             15 * time.Minute,
+				MaxNodeStartupTime:               35 * time.Minute,
 			},
 		},
 		{

cluster-autoscaler/cloudprovider/coreweave/coreweave_nodegroup.go

@@ -18,13 +18,13 @@ package coreweave
 
 import (
 	"fmt"
+	"sync"
 
 	apiv1 "k8s.io/api/core/v1"
 	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider"
 	"k8s.io/autoscaler/cluster-autoscaler/config"
 	"k8s.io/autoscaler/cluster-autoscaler/simulator/framework"
 	"k8s.io/klog/v2"
-	"sync"
 )
 
 // CoreWeaveNodeGroup represents a node group in the CoreWeave cloud provider.
@@ -84,13 +84,6 @@ func (ng *CoreWeaveNodeGroup) DeleteNodes(nodes []*apiv1.Node) error {
 	if err != nil {
 		return fmt.Errorf("some nodes do not belong to node group %s: %v", ng.Name, err)
 	}
-	// If we reach here, it means we can delete the nodes
-	for _, node := range nodes {
-		// Mark the node for removal
-		if err := ng.nodepool.MarkNodeForRemoval(node); err != nil {
-			return fmt.Errorf("failed to mark node %s for removal: %v", node.Name, err)
-		}
-	}
 	//update target size
 	if err := ng.nodepool.SetSize(ng.nodepool.GetTargetSize() - len(nodes)); err != nil {
 		return fmt.Errorf("failed to update target size after marking nodes for removal: %v", err)
@@ -107,6 +100,9 @@ func (ng *CoreWeaveNodeGroup) ForceDeleteNodes(nodes []*apiv1.Node) error {
 // DecreaseTargetSize decreases the target size of the node group by the specified delta.
 func (ng *CoreWeaveNodeGroup) DecreaseTargetSize(delta int) error {
 	klog.V(4).Infof("Decreasing target size of node group %s by %d", ng.Name, delta)
+	if delta < 0 {
+		delta = -delta
+	}
 	return ng.nodepool.SetSize(ng.nodepool.GetTargetSize() - delta)
 }
 

cluster-autoscaler/cloudprovider/coreweave/coreweave_nodegroup_test.go

@@ -20,6 +20,8 @@ import (
 	"context"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	apiv1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
@@ -109,18 +111,92 @@ func TestIncreaseSize(t *testing.T) {
 }
 
 func TestDeleteNodes(t *testing.T) {
-	ng := makeTestNodeGroup("ng-1", "uid-1", 0, 5, 3)
-	validNode := &apiv1.Node{
-		ObjectMeta: metav1.ObjectMeta{
-			Name:   "node1",
-			Labels: map[string]string{coreWeaveNodePoolUID: "uid-1"},
+	initialTargetSize := int64(3)
+
+	testCases := map[string]struct {
+		nodesToDelete      []*apiv1.Node
+		expectedTargetSize int
+		expectedError      error
+	}{
+		"reduce-target-size-by-one-node": {
+			nodesToDelete: []*apiv1.Node{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:   "node1",
+						Labels: map[string]string{coreWeaveNodePoolUID: "uid-1"},
+					},
+				},
+			},
+			expectedTargetSize: 2,
+		},
+		"reduce-target-size-by-three-node": {
+			nodesToDelete: []*apiv1.Node{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:   "node1",
+						Labels: map[string]string{coreWeaveNodePoolUID: "uid-1"},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:   "node2",
+						Labels: map[string]string{coreWeaveNodePoolUID: "uid-1"},
+					},
+				},
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:   "node3",
+						Labels: map[string]string{coreWeaveNodePoolUID: "uid-1"},
+					},
+				},
+			},
+			expectedTargetSize: 0,
 		},
 	}
-	nodes := []*apiv1.Node{
-		validNode,
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			ng := makeTestNodeGroup("ng-1", "uid-1", 0, 5, initialTargetSize)
+
+			err := ng.DeleteNodes(tc.nodesToDelete)
+			if tc.expectedError != nil {
+				require.Equal(t, tc.expectedError, err)
+				return
+			}
+			require.NoError(t, err)
+			require.Equal(t, ng.nodepool.GetTargetSize(), tc.expectedTargetSize)
+		})
 	}
-	err := ng.DeleteNodes(nodes)
-	if err != nil && err != cloudprovider.ErrNotImplemented {
-		t.Errorf("expected ErrNotImplemented or nil, got %v", err)
+}
+
+func TestDecreaseTargetSize(t *testing.T) {
+	testCases := map[string]struct {
+		delta              int
+		expectedTargetSize int
+		expectedError      error
+	}{
+		"positive-delta": {
+			delta:              2,
+			expectedTargetSize: 1,
+		},
+		"negative-delta": {
+			delta:              -2,
+			expectedTargetSize: 1,
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			ng := makeTestNodeGroup("ng-1", "uid-1", 1, 5, 3)
+
+			err := ng.DecreaseTargetSize(tc.delta)
+			if tc.expectedError != nil {
+				require.Error(t, err)
+				require.Equal(t, tc.expectedError, err)
+				return
+			}
+			require.NoError(t, err)
+			require.Equal(t, tc.expectedTargetSize, ng.nodepool.GetTargetSize())
+		})
 	}
 }

cluster-autoscaler/cloudprovider/coreweave/coreweave_nodepool.go

@@ -187,42 +187,6 @@ func (np *CoreWeaveNodePool) SetSize(size int) error {
 	return nil
 }
 
-// MarkNodeForRemoval marks a node for removal from the node pool.
-func (np *CoreWeaveNodePool) MarkNodeForRemoval(node *apiv1.Node) error {
-	ctx, cancel := GetCoreWeaveContext()
-	defer cancel()
-	if node == nil {
-		return fmt.Errorf("node cannot be nil")
-	}
-	if node.Name == "" {
-		return fmt.Errorf("node name cannot be empty")
-	}
-	// Log the node being marked for removal
-	klog.V(4).Infof("Marking node %s for removal from node pool %s", node.Name, np.GetName())
-	// Fetch the current node object
-	currentNode, err := np.client.CoreV1().Nodes().Get(ctx, node.Name, metav1.GetOptions{})
-	if err != nil {
-		return fmt.Errorf("failed to get node %s: %v", node.Name, err)
-	}
-	// Check if the node belongs to this node pool
-	if currentNode.Labels == nil || currentNode.Labels[coreWeaveNodePoolUID] != np.GetUID() {
-		return fmt.Errorf("node %s does not belong to node pool %s", node.Name, np.GetName())
-	}
-	// Check if the node is already marked for removal
-	if currentNode.Labels != nil && currentNode.Labels[coreWeaveRemoveNode] == "true" {
-		klog.V(4).Infof("Node %s is already marked for removal", currentNode.Name)
-		return nil // Node is already marked for removal, no action needed
-	}
-	// Set the label to indicate the node should be removed
-	currentNode.Labels[coreWeaveRemoveNode] = "true"
-	// Update the node using the client
-	_, err = np.client.CoreV1().Nodes().Update(ctx, currentNode, metav1.UpdateOptions{})
-	if err != nil {
-		return fmt.Errorf("failed to mark node %s for removal: %v", node.Name, err)
-	}
-	return nil
-}
-
 // ValidateNodes checks if the provided nodes belong to the node pool.
 func (np *CoreWeaveNodePool) ValidateNodes(nodes []*apiv1.Node) error {
 	if len(nodes) == 0 {