fix: Ensure volumes are detached before deleting node

kwok/charts/templates/clusterrole.yaml

@@ -36,7 +36,7 @@ rules:
     resources: ["pods", "nodes", "persistentvolumes", "persistentvolumeclaims", "replicationcontrollers", "namespaces"]
     verbs: ["get", "list", "watch"]
   - apiGroups: ["storage.k8s.io"]
-    resources: ["storageclasses", "csinodes"]
+    resources: ["storageclasses", "csinodes", "volumeattachments"]
     verbs: ["get", "watch", "list"]
   - apiGroups: ["apps"]
     resources: ["daemonsets", "deployments", "replicasets", "statefulsets"]

pkg/controllers/controllers.go

@@ -77,7 +77,7 @@ func NewControllers(
 		informer.NewPodController(kubeClient, cluster),
 		informer.NewNodePoolController(kubeClient, cluster),
 		informer.NewNodeClaimController(kubeClient, cluster),
-		termination.NewController(kubeClient, cloudProvider, terminator.NewTerminator(clock, kubeClient, evictionQueue, recorder), recorder),
+		termination.NewController(clock, kubeClient, cloudProvider, terminator.NewTerminator(clock, kubeClient, evictionQueue, recorder), recorder),
 		metricspod.NewController(kubeClient),
 		metricsnodepool.NewController(kubeClient),
 		metricsnode.NewController(cluster),

pkg/controllers/node/termination/controller.go

@@ -21,15 +21,16 @@ import (
 	"fmt"
 	"time"
 
-	"k8s.io/apimachinery/pkg/api/errors"
-
-	"sigs.k8s.io/karpenter/pkg/utils/termination"
-
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/samber/lo"
 	"golang.org/x/time/rate"
 	corev1 "k8s.io/api/core/v1"
+	storagev1 "k8s.io/api/storage/v1"
 	"k8s.io/apimachinery/pkg/api/equality"
+	"k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/client-go/util/workqueue"
+	"k8s.io/utils/clock"
 	controllerruntime "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller"
@@ -38,28 +39,32 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/manager"
 	"sigs.k8s.io/controller-runtime/pkg/reconcile"
 
-	"sigs.k8s.io/karpenter/pkg/operator/injection"
-
 	v1 "sigs.k8s.io/karpenter/pkg/apis/v1"
 	"sigs.k8s.io/karpenter/pkg/cloudprovider"
 	"sigs.k8s.io/karpenter/pkg/controllers/node/termination/terminator"
 	terminatorevents "sigs.k8s.io/karpenter/pkg/controllers/node/termination/terminator/events"
 	"sigs.k8s.io/karpenter/pkg/events"
 	"sigs.k8s.io/karpenter/pkg/metrics"
+	"sigs.k8s.io/karpenter/pkg/operator/injection"
 	nodeutils "sigs.k8s.io/karpenter/pkg/utils/node"
+	"sigs.k8s.io/karpenter/pkg/utils/pod"
+	"sigs.k8s.io/karpenter/pkg/utils/termination"
+	volumeutil "sigs.k8s.io/karpenter/pkg/utils/volume"
 )
 
 // Controller for the resource
 type Controller struct {
+	clock         clock.Clock
 	kubeClient    client.Client
 	cloudProvider cloudprovider.CloudProvider
 	terminator    *terminator.Terminator
 	recorder      events.Recorder
 }
 
 // NewController constructs a controller instance
-func NewController(kubeClient client.Client, cloudProvider cloudprovider.CloudProvider, terminator *terminator.Terminator, recorder events.Recorder) *Controller {
+func NewController(clk clock.Clock, kubeClient client.Client, cloudProvider cloudprovider.CloudProvider, terminator *terminator.Terminator, recorder events.Recorder) *Controller {
 	return &Controller{
+		clock:         clk,
 		kubeClient:    kubeClient,
 		cloudProvider: cloudProvider,
 		terminator:    terminator,
@@ -119,6 +124,18 @@ func (c *Controller) finalize(ctx context.Context, node *corev1.Node) (reconcile
 
 		return reconcile.Result{RequeueAfter: 1 * time.Second}, nil
 	}
+	// In order for Pods associated with PersistentVolumes to smoothly migrate from the terminating Node, we wait
+	// for VolumeAttachments of drain-able Pods to be cleaned up before terminating Node and removing its finalizer.
+	// However, if TerminationGracePeriod is configured for Node, and we are past that period, we will skip waiting.
+	if nodeTerminationTime == nil || c.clock.Now().Before(*nodeTerminationTime) {
+		areVolumesDetached, err := c.ensureVolumesDetached(ctx, node)
+		if err != nil {
+			return reconcile.Result{}, fmt.Errorf("ensuring no volume attachments, %w", err)
+		}
+		if !areVolumesDetached {
+			return reconcile.Result{RequeueAfter: 1 * time.Second}, nil
+		}
+	}
 	nodeClaims, err = nodeutils.GetNodeClaims(ctx, node, c.kubeClient)
 	if err != nil {
 		return reconcile.Result{}, fmt.Errorf("deleting nodeclaims, %w", err)
@@ -158,6 +175,58 @@ func (c *Controller) deleteAllNodeClaims(ctx context.Context, nodeClaims ...*v1.
 	return nil
 }
 
+func (c *Controller) ensureVolumesDetached(ctx context.Context, node *corev1.Node) (volumesDetached bool, err error) {
+	volumeAttachments, err := nodeutils.GetVolumeAttachments(ctx, c.kubeClient, node)
+	if err != nil {
+		return false, err
+	}
+	// Filter out VolumeAttachments associated with not drain-able Pods
+	filteredVolumeAttachments, err := filterVolumeAttachments(ctx, c.kubeClient, node, volumeAttachments, c.clock)
+	if err != nil {
+		return false, err
+	}
+	return len(filteredVolumeAttachments) == 0, nil
+}
+
+// filterVolumeAttachments filters out storagev1.VolumeAttachments that should not block the termination
+// of the passed corev1.Node
+func filterVolumeAttachments(ctx context.Context, kubeClient client.Client, node *corev1.Node, volumeAttachments []*storagev1.VolumeAttachment, clk clock.Clock) ([]*storagev1.VolumeAttachment, error) {
+	// No need to filter empty VolumeAttachments list
+	if len(volumeAttachments) == 0 {
+		return volumeAttachments, nil
+	}
+	// Create list of non-drain-able Pods associated with Node
+	pods, err := nodeutils.GetPods(ctx, kubeClient, node)
+	if err != nil {
+		return nil, err
+	}
+	unDrainablePods := lo.Reject(pods, func(p *corev1.Pod, _ int) bool {
+		return pod.IsDrainable(p, clk)
+	})
+	// Filter out VolumeAttachments associated with non-drain-able Pods
+	// Match on Pod -> PersistentVolumeClaim -> PersistentVolume Name <- VolumeAttachment
+	shouldFilterOutVolume := sets.New[string]()
+	for _, p := range unDrainablePods {
+		for _, v := range p.Spec.Volumes {
+			pvc, err := volumeutil.GetPersistentVolumeClaim(ctx, kubeClient, p, v)
+			if errors.IsNotFound(err) {
+				continue
+			}
+			if err != nil {
+				return nil, err
+			}
+			if pvc != nil {
+				shouldFilterOutVolume.Insert(pvc.Spec.VolumeName)
+			}
+		}
+	}
+	filteredVolumeAttachments := lo.Reject(volumeAttachments, func(v *storagev1.VolumeAttachment, _ int) bool {
+		pvName := v.Spec.Source.PersistentVolumeName
+		return pvName == nil || shouldFilterOutVolume.Has(*pvName)
+	})
+	return filteredVolumeAttachments, nil
+}
+
 func (c *Controller) removeFinalizer(ctx context.Context, n *corev1.Node) error {
 	stored := n.DeepCopy()
 	controllerutil.RemoveFinalizer(n, v1.TerminationFinalizer)

pkg/controllers/node/termination/suite_test.go

@@ -64,12 +64,12 @@ func TestAPIs(t *testing.T) {
 
 var _ = BeforeSuite(func() {
 	fakeClock = clock.NewFakeClock(time.Now())
-	env = test.NewEnvironment(test.WithCRDs(apis.CRDs...), test.WithCRDs(v1alpha1.CRDs...), test.WithFieldIndexers(test.NodeClaimFieldIndexer(ctx)))
+	env = test.NewEnvironment(test.WithCRDs(apis.CRDs...), test.WithCRDs(v1alpha1.CRDs...), test.WithFieldIndexers(test.NodeClaimFieldIndexer(ctx), test.VolumeAttachmentFieldIndexer(ctx)))
 
 	cloudProvider = fake.NewCloudProvider()
 	recorder = test.NewEventRecorder()
 	queue = terminator.NewQueue(env.Client, recorder)
-	terminationController = termination.NewController(env.Client, cloudProvider, terminator.NewTerminator(fakeClock, env.Client, queue, recorder), recorder)
+	terminationController = termination.NewController(fakeClock, env.Client, cloudProvider, terminator.NewTerminator(fakeClock, env.Client, queue, recorder), recorder)
 })
 
 var _ = AfterSuite(func() {

pkg/operator/operator.go

@@ -35,6 +35,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	coordinationv1 "k8s.io/api/coordination/v1"
 	corev1 "k8s.io/api/core/v1"
+	storagev1 "k8s.io/api/storage/v1"
 	"k8s.io/klog/v2"
 	"knative.dev/pkg/changeset"
 	ctrl "sigs.k8s.io/controller-runtime"
@@ -218,6 +219,9 @@ func NewOperator() (context.Context, *Operator) {
 	lo.Must0(mgr.GetFieldIndexer().IndexField(ctx, &v1.NodePool{}, "spec.template.spec.nodeClassRef.name", func(o client.Object) []string {
 		return []string{o.(*v1.NodePool).Spec.Template.Spec.NodeClassRef.Name}
 	}), "failed to setup nodepool nodeclassref name indexer")
+	lo.Must0(mgr.GetFieldIndexer().IndexField(ctx, &storagev1.VolumeAttachment{}, "spec.nodeName", func(o client.Object) []string {
+		return []string{o.(*storagev1.VolumeAttachment).Spec.NodeName}
+	}), "failed to setup volumeattachment indexer")
 
 	lo.Must0(mgr.AddHealthzCheck("healthz", healthz.Ping))
 	lo.Must0(mgr.AddReadyzCheck("readyz", healthz.Ping))

pkg/test/environment.go

@@ -25,6 +25,7 @@ import (
 	"github.com/awslabs/operatorpkg/option"
 	"github.com/samber/lo"
 	corev1 "k8s.io/api/core/v1"
+	storagev1 "k8s.io/api/storage/v1"
 	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
 	"k8s.io/apimachinery/pkg/util/version"
 	"k8s.io/client-go/kubernetes"
@@ -75,6 +76,14 @@ func NodeClaimFieldIndexer(ctx context.Context) func(cache.Cache) error {
 	}
 }
 
+func VolumeAttachmentFieldIndexer(ctx context.Context) func(cache.Cache) error {
+	return func(c cache.Cache) error {
+		return c.IndexField(ctx, &storagev1.VolumeAttachment{}, "spec.nodeName", func(obj client.Object) []string {
+			return []string{obj.(*storagev1.VolumeAttachment).Spec.NodeName}
+		})
+	}
+}
+
 func NewEnvironment(options ...option.Function[EnvironmentOptions]) *Environment {
 	opts := option.Resolve(options...)
 	ctx, cancel := context.WithCancel(context.Background())

pkg/utils/node/node.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 
 	corev1 "k8s.io/api/core/v1"
+	storagev1 "k8s.io/api/storage/v1"
 
 	v1 "sigs.k8s.io/karpenter/pkg/apis/v1"
 
@@ -143,6 +144,17 @@ func GetProvisionablePods(ctx context.Context, kubeClient client.Client) ([]*cor
 	}), nil
 }
 
+// GetVolumeAttachments grabs all volumeAttachments associated with the passed node
+func GetVolumeAttachments(ctx context.Context, kubeClient client.Client, node *corev1.Node) ([]*storagev1.VolumeAttachment, error) {
+	var volumeAttachmentList storagev1.VolumeAttachmentList
+	if err := kubeClient.List(ctx, &volumeAttachmentList, client.MatchingFields{"spec.nodeName": node.Name}); err != nil {
+		return nil, fmt.Errorf("listing volumeattachments, %w", err)
+	}
+	return lo.FilterMap(volumeAttachmentList.Items, func(v storagev1.VolumeAttachment, _ int) (*storagev1.VolumeAttachment, bool) {
+		return &v, v.Spec.NodeName == node.Name
+	}), nil
+}
+
 func GetCondition(n *corev1.Node, match corev1.NodeConditionType) corev1.NodeCondition {
 	for _, condition := range n.Status.Conditions {
 		if condition.Type == match {

pkg/utils/pod/scheduling.go

@@ -62,14 +62,20 @@ func IsEvictable(pod *corev1.Pod) bool {
 
 // IsWaitingEviction checks if this is a pod that we are waiting to be removed from the node by ensuring that the pod:
 // - Isn't a terminal pod (Failed or Succeeded)
-// - Isn't a pod that has been terminating past its terminationGracePeriodSeconds
+// - Can be drained by Karpenter (See IsDrainable)
+func IsWaitingEviction(pod *corev1.Pod, clk clock.Clock) bool {
+	return !IsTerminal(pod) &&
+		IsDrainable(pod, clk)
+}
+
+// IsDrainable checks if a pod can be drained by Karpenter by ensuring that the pod:
 // - Doesn't tolerate the "karpenter.sh/disruption=disrupting" taint
+// - Isn't a pod that has been terminating past its terminationGracePeriodSeconds
 // - Isn't a mirror pod (https://kubernetes.io/docs/tasks/configure-pod-container/static-pod/)
 // Note: pods with the `karpenter.sh/do-not-disrupt` annotation are included since node drain should stall until these pods are evicted or become terminal, even though Karpenter won't orchestrate the eviction.
-func IsWaitingEviction(pod *corev1.Pod, clk clock.Clock) bool {
-	return !IsTerminal(pod) &&
+func IsDrainable(pod *corev1.Pod, clk clock.Clock) bool {
+	return !ToleratesDisruptedNoScheduleTaint(pod) &&
 		!IsStuckTerminating(pod, clk) &&
-		!ToleratesDisruptedNoScheduleTaint(pod) &&
 		// Mirror pods cannot be deleted through the API server since they are created and managed by kubelet
 		// This means they are effectively read-only and can't be controlled by API server calls
 		// https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#drain