Revert "Drain nodes in parallel (#4864)" (#4964)

This reverts commit 391a6ce.

go.mod

@@ -335,7 +335,6 @@ require (
 	github.com/olekukonko/tablewriter v0.0.5 // indirect
 	github.com/opencontainers/go-digest v1.0.0 // indirect
 	github.com/opencontainers/image-spec v1.0.2 // indirect
-	github.com/orcaman/concurrent-map v1.0.0 // indirect
 	github.com/peterbourgon/diskv v2.0.1+incompatible // indirect
 	github.com/phayes/checkstyle v0.0.0-20170904204023-bfd46e6a821d // indirect
 	github.com/pierrec/lz4 v2.0.5+incompatible // indirect

go.sum

@@ -1929,8 +1929,6 @@ github.com/openzipkin-contrib/zipkin-go-opentracing v0.4.5/go.mod h1:/wsWhb9smxS
 github.com/openzipkin/zipkin-go v0.1.6/go.mod h1:QgAqvLzwWbR/WpD4A3cGpPtJrZXNIiJc5AZX7/PBEpw=
 github.com/openzipkin/zipkin-go v0.2.1/go.mod h1:NaW6tEwdmWMaCDZzg8sh+IBNOxHMPnhQw8ySjnjRyN4=
 github.com/openzipkin/zipkin-go v0.2.2/go.mod h1:NaW6tEwdmWMaCDZzg8sh+IBNOxHMPnhQw8ySjnjRyN4=
-github.com/orcaman/concurrent-map v1.0.0 h1:I/2A2XPCb4IuQWcQhBhSwGfiuybl/J0ev9HDbW65HOY=
-github.com/orcaman/concurrent-map v1.0.0/go.mod h1:Lu3tH6HLW3feq74c2GC+jIMS/K2CFcDWnWD9XkenwhI=
 github.com/otiai10/copy v1.2.0/go.mod h1:rrF5dJ5F0t/EWSYODDu4j9/vEeYHMkc8jt0zJChqQWw=
 github.com/otiai10/copy v1.7.0 h1:hVoPiN+t+7d2nzzwMiDHPSOogsWAStewq3TwU05+clE=
 github.com/otiai10/copy v1.7.0/go.mod h1:rmRl6QPdJj6EiUqXQ/4Nn2lLXoNQjFCQbbNrxgc/t3U=

integration/tests/unowned_cluster/unowned_cluster_test.go

@@ -319,7 +319,6 @@ var _ = Describe("(Integration) [non-eksctl cluster & nodegroup support]", func(
 			WithArgs(
 				"--cluster", params.ClusterName,
 				"--name", mng1,
-				"--parallel", "2",
 				"--verbose", "2",
 			)
 		Expect(cmd).To(RunSuccessfully())

pkg/actions/nodegroup/drain.go

@@ -15,13 +15,12 @@ type DrainInput struct {
 	NodeDrainWaitPeriod time.Duration
 	Undo                bool
 	DisableEviction     bool
-	Parallel            int
 }
 
 func (m *Manager) Drain(input *DrainInput) error {
 	if !input.Plan {
 		for _, n := range input.NodeGroups {
-			nodeGroupDrainer := drain.NewNodeGroupDrainer(m.clientSet, n, m.ctl.Provider.WaitTimeout(), input.MaxGracePeriod, input.NodeDrainWaitPeriod, input.Undo, input.DisableEviction, input.Parallel)
+			nodeGroupDrainer := drain.NewNodeGroupDrainer(m.clientSet, n, m.ctl.Provider.WaitTimeout(), input.MaxGracePeriod, input.NodeDrainWaitPeriod, input.Undo, input.DisableEviction)
 			if err := nodeGroupDrainer.Drain(); err != nil {
 				return err
 			}

pkg/ctl/cmdutils/configfile.go

@@ -4,7 +4,6 @@ import (
 	"encoding/csv"
 	"fmt"
 	"reflect"
-	"strconv"
 	"strings"
 
 	"github.com/kris-nova/logger"
@@ -518,8 +517,8 @@ func normalizeBaseNodeGroup(np api.NodePool, cmd *cobra.Command) {
 	}
 }
 
-// NewDeleteAndDrainNodeGroupLoader will load config or use flags for 'eksctl delete nodegroup'
-func NewDeleteAndDrainNodeGroupLoader(cmd *Cmd, ng *api.NodeGroup, ngFilter *filter.NodeGroupFilter) ClusterConfigLoader {
+// NewDeleteNodeGroupLoader will load config or use flags for 'eksctl delete nodegroup'
+func NewDeleteNodeGroupLoader(cmd *Cmd, ng *api.NodeGroup, ngFilter *filter.NodeGroupFilter) ClusterConfigLoader {
 	l := newCommonClusterConfigLoader(cmd)
 
 	l.validateWithConfigFile = func() error {
@@ -547,12 +546,6 @@ func NewDeleteAndDrainNodeGroupLoader(cmd *Cmd, ng *api.NodeGroup, ngFilter *fil
 			return ErrMustBeSet("--name")
 		}
 
-		if flag := l.CobraCommand.Flag("parallel"); flag != nil && flag.Changed {
-			if val, _ := strconv.Atoi(flag.Value.String()); val > 25 || val < 1 {
-				return fmt.Errorf("--parallel value must be of range 1-25")
-			}
-		}
-
 		ngFilter.AppendIncludeNames(ng.Name)
 
 		l.Plan = false

pkg/ctl/delete/nodegroup.go

@@ -17,30 +17,25 @@ import (
 )
 
 func deleteNodeGroupCmd(cmd *cmdutils.Cmd) {
-	deleteNodeGroupWithRunFunc(cmd, func(cmd *cmdutils.Cmd, ng *api.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool, parallel int) error {
-		return doDeleteNodeGroup(cmd, ng, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing, maxGracePeriod, disableEviction, parallel)
+	deleteNodeGroupWithRunFunc(cmd, func(cmd *cmdutils.Cmd, ng *api.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool) error {
+		return doDeleteNodeGroup(cmd, ng, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing, maxGracePeriod, disableEviction)
 	})
 }
 
-func deleteNodeGroupWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd, ng *api.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool, parallel int) error) {
+func deleteNodeGroupWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd, ng *api.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool) error) {
 	cfg := api.NewClusterConfig()
 	ng := api.NewNodeGroup()
 	cmd.ClusterConfig = cfg
 
-	var (
-		updateAuthConfigMap  bool
-		deleteNodeGroupDrain bool
-		onlyMissing          bool
-		maxGracePeriod       time.Duration
-		disableEviction      bool
-		parallel             int
-	)
+	var updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool
+	var maxGracePeriod time.Duration
+	var disableEviction bool
 
 	cmd.SetDescription("nodegroup", "Delete a nodegroup", "", "ng")
 
 	cmd.CobraCommand.RunE = func(_ *cobra.Command, args []string) error {
 		cmd.NameArg = cmdutils.GetNameArg(args)
-		return runFunc(cmd, ng, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing, maxGracePeriod, disableEviction, parallel)
+		return runFunc(cmd, ng, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing, maxGracePeriod, disableEviction)
 	}
 
 	cmd.FlagSetGroup.InFlagSet("General", func(fs *pflag.FlagSet) {
@@ -57,7 +52,6 @@ func deleteNodeGroupWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cm
 		fs.DurationVar(&maxGracePeriod, "max-grace-period", defaultMaxGracePeriod, "Maximum pods termination grace period")
 		defaultDisableEviction := false
 		fs.BoolVar(&disableEviction, "disable-eviction", defaultDisableEviction, "Force drain to use delete, even if eviction is supported. This will bypass checking PodDisruptionBudgets, use with caution.")
-		fs.IntVar(&parallel, "parallel", 1, "Number of nodes to drain in parallel. Max 25")
 
 		cmd.Wait = false
 		cmdutils.AddWaitFlag(fs, &cmd.Wait, "deletion of all resources")
@@ -67,10 +61,10 @@ func deleteNodeGroupWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cm
 	cmdutils.AddCommonFlagsForAWS(cmd.FlagSetGroup, &cmd.ProviderConfig, true)
 }
 
-func doDeleteNodeGroup(cmd *cmdutils.Cmd, ng *api.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool, parallel int) error {
+func doDeleteNodeGroup(cmd *cmdutils.Cmd, ng *api.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool) error {
 	ngFilter := filter.NewNodeGroupFilter()
 
-	if err := cmdutils.NewDeleteAndDrainNodeGroupLoader(cmd, ng, ngFilter).Load(); err != nil {
+	if err := cmdutils.NewDeleteNodeGroupLoader(cmd, ng, ngFilter).Load(); err != nil {
 		return err
 	}
 
@@ -132,7 +126,6 @@ func doDeleteNodeGroup(cmd *cmdutils.Cmd, ng *api.NodeGroup, updateAuthConfigMap
 			Plan:            cmd.Plan,
 			MaxGracePeriod:  maxGracePeriod,
 			DisableEviction: disableEviction,
-			Parallel:        parallel,
 		}
 		err := nodeGroupManager.Drain(drainInput)
 		if err != nil {

pkg/ctl/delete/nodegroup_test.go

@@ -22,7 +22,7 @@ var _ = Describe("delete", func() {
 			cmd := newMockEmptyCmd(args...)
 			count := 0
 			cmdutils.AddResourceCmd(cmdutils.NewGrouping(), cmd.parentCmd, func(cmd *cmdutils.Cmd) {
-				deleteNodeGroupWithRunFunc(cmd, func(cmd *cmdutils.Cmd, ng *v1alpha5.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool, parallel int) error {
+				deleteNodeGroupWithRunFunc(cmd, func(cmd *cmdutils.Cmd, ng *v1alpha5.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool) error {
 					Expect(cmd.ClusterConfig.Metadata.Name).To(Equal("clusterName"))
 					Expect(ng.Name).To(Equal("ng"))
 					count++
@@ -52,14 +52,5 @@ var _ = Describe("delete", func() {
 			args:  []string{"nodegroup", "ng", "--cluster", "dummy", "--name", "ng"},
 			error: fmt.Errorf("Error: --name=ng and argument ng cannot be used at the same time"),
 		}),
-
-		Entry("setting --parallel below 1", invalidParamsCase{
-			args:  []string{"nodegroup", "--cluster", "dummy", "--name", "ng", "--parallel", "-1"},
-			error: fmt.Errorf("Error: --parallel value must be of range 1-25"),
-		}),
-		Entry("setting --parallel above 25", invalidParamsCase{
-			args:  []string{"nodegroup", "--cluster", "dummy", "--name", "ng", "--parallel", "26"},
-			error: fmt.Errorf("Error: --parallel value must be of range 1-25"),
-		}),
 	)
 })

pkg/ctl/drain/nodegroup.go

@@ -15,30 +15,26 @@ import (
 )
 
 func drainNodeGroupCmd(cmd *cmdutils.Cmd) {
-	drainNodeGroupWithRunFunc(cmd, func(cmd *cmdutils.Cmd, ng *api.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool, parallel int) error {
-		return doDrainNodeGroup(cmd, ng, undo, onlyMissing, maxGracePeriod, nodeDrainWaitPeriod, disableEviction, parallel)
+	drainNodeGroupWithRunFunc(cmd, func(cmd *cmdutils.Cmd, ng *api.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool) error {
+		return doDrainNodeGroup(cmd, ng, undo, onlyMissing, maxGracePeriod, nodeDrainWaitPeriod, disableEviction)
 	})
 }
 
-func drainNodeGroupWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd, ng *api.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool, parallel int) error) {
+func drainNodeGroupWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd, ng *api.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool) error) {
 	cfg := api.NewClusterConfig()
 	ng := api.NewNodeGroup()
 	cmd.ClusterConfig = cfg
 
-	var (
-		undo                bool
-		onlyMissing         bool
-		disableEviction     bool
-		parallel            int
-		maxGracePeriod      time.Duration
-		nodeDrainWaitPeriod time.Duration
-	)
+	var undo, onlyMissing bool
+	var maxGracePeriod time.Duration
+	var nodeDrainWaitPeriod time.Duration
+	var disableEviction bool
 
 	cmd.SetDescription("nodegroup", "Cordon and drain a nodegroup", "", "ng")
 
 	cmd.CobraCommand.RunE = func(_ *cobra.Command, args []string) error {
 		cmd.NameArg = cmdutils.GetNameArg(args)
-		return runFunc(cmd, ng, undo, onlyMissing, maxGracePeriod, nodeDrainWaitPeriod, disableEviction, parallel)
+		return runFunc(cmd, ng, undo, onlyMissing, maxGracePeriod, nodeDrainWaitPeriod, disableEviction)
 	}
 
 	cmd.FlagSetGroup.InFlagSet("General", func(fs *pflag.FlagSet) {
@@ -56,16 +52,15 @@ func drainNodeGroupWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd
 		fs.BoolVar(&disableEviction, "disable-eviction", defaultDisableEviction, "Force drain to use delete, even if eviction is supported. This will bypass checking PodDisruptionBudgets, use with caution.")
 		cmdutils.AddTimeoutFlag(fs, &cmd.ProviderConfig.WaitTimeout)
 		fs.DurationVar(&nodeDrainWaitPeriod, "node-drain-wait-period", 0, "Amount of time to wait between draining nodes in a nodegroup")
-		fs.IntVar(&parallel, "parallel", 1, "Number of nodes to drain in parallel. Max 25")
 	})
 
 	cmdutils.AddCommonFlagsForAWS(cmd.FlagSetGroup, &cmd.ProviderConfig, true)
 }
 
-func doDrainNodeGroup(cmd *cmdutils.Cmd, ng *api.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool, parallel int) error {
+func doDrainNodeGroup(cmd *cmdutils.Cmd, ng *api.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool) error {
 	ngFilter := filter.NewNodeGroupFilter()
 
-	if err := cmdutils.NewDeleteAndDrainNodeGroupLoader(cmd, ng, ngFilter).Load(); err != nil {
+	if err := cmdutils.NewDeleteNodeGroupLoader(cmd, ng, ngFilter).Load(); err != nil {
 		return err
 	}
 
@@ -131,7 +126,6 @@ func doDrainNodeGroup(cmd *cmdutils.Cmd, ng *api.NodeGroup, undo, onlyMissing bo
 		NodeDrainWaitPeriod: nodeDrainWaitPeriod,
 		Undo:                undo,
 		DisableEviction:     disableEviction,
-		Parallel:            parallel,
 	}
 	return nodegroup.New(cfg, ctl, clientSet).Drain(drainInput)
 }

pkg/ctl/drain/nodegroup_test.go

@@ -24,7 +24,7 @@ var _ = Describe("drain node group", func() {
 			cmd := newMockEmptyCmd(args...)
 			count := 0
 			cmdutils.AddResourceCmd(cmdutils.NewGrouping(), cmd.parentCmd, func(cmd *cmdutils.Cmd) {
-				drainNodeGroupWithRunFunc(cmd, func(cmd *cmdutils.Cmd, ng *v1alpha5.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool, parallel int) error {
+				drainNodeGroupWithRunFunc(cmd, func(cmd *cmdutils.Cmd, ng *v1alpha5.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool) error {
 					Expect(cmd.ClusterConfig.Metadata.Name).To(Equal("clusterName"))
 					Expect(ng.Name).To(Equal("ng"))
 					count++
@@ -54,13 +54,5 @@ var _ = Describe("drain node group", func() {
 			args:  []string{"nodegroup", "ng", "--cluster", "dummy", "--name", "ng"},
 			error: fmt.Errorf("Error: --name=ng and argument ng cannot be used at the same time"),
 		}),
-		Entry("setting --parallel below 1", invalidParamsCase{
-			args:  []string{"nodegroup", "--cluster", "dummy", "--name", "ng", "--parallel", "-1"},
-			error: fmt.Errorf("Error: --parallel value must be of range 1-25"),
-		}),
-		Entry("setting --parallel above 25", invalidParamsCase{
-			args:  []string{"nodegroup", "--cluster", "dummy", "--name", "ng", "--parallel", "26"},
-			error: fmt.Errorf("Error: --parallel value must be of range 1-25"),
-		}),
 	)
 })

pkg/drain/nodegroup.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"time"
 
-	"golang.org/x/sync/semaphore"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	"github.com/weaveworks/eksctl/pkg/drain/evictor"
@@ -16,7 +15,6 @@ import (
 	"github.com/pkg/errors"
 	"github.com/weaveworks/eksctl/pkg/eks"
 
-	cmap "github.com/orcaman/concurrent-map"
 	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/client-go/kubernetes"
 )
@@ -42,10 +40,9 @@ type NodeGroupDrainer struct {
 	waitTimeout         time.Duration
 	nodeDrainWaitPeriod time.Duration
 	undo                bool
-	parallel            int
 }
 
-func NewNodeGroupDrainer(clientSet kubernetes.Interface, ng eks.KubeNodeGroup, waitTimeout, maxGracePeriod, nodeDrainWaitPeriod time.Duration, undo, disableEviction bool, parallel int) NodeGroupDrainer {
+func NewNodeGroupDrainer(clientSet kubernetes.Interface, ng eks.KubeNodeGroup, waitTimeout, maxGracePeriod, nodeDrainWaitPeriod time.Duration, undo, disableEviction bool) NodeGroupDrainer {
 	ignoreDaemonSets := []metav1.ObjectMeta{
 		{
 			Namespace: "kube-system",
@@ -79,7 +76,6 @@ func NewNodeGroupDrainer(clientSet kubernetes.Interface, ng eks.KubeNodeGroup, w
 		waitTimeout:         waitTimeout,
 		nodeDrainWaitPeriod: nodeDrainWaitPeriod,
 		undo:                undo,
-		parallel:            parallel,
 	}
 }
 
@@ -105,20 +101,15 @@ func (n *NodeGroupDrainer) Drain() error {
 		return nil // no need to kill any pods
 	}
 
-	drainedNodes := cmap.New()
-	ctx, cancel := context.WithTimeout(context.TODO(), n.waitTimeout)
-	defer cancel()
-
-	parallelLimit := int64(n.parallel)
-	sem := semaphore.NewWeighted(parallelLimit)
-	logger.Info("starting parallel draining, max in-flight of %d", parallelLimit)
+	drainedNodes := sets.NewString()
 	// loop until all nodes are drained to handle accidental scale-up
 	// or any other changes in the ASG
+	timer := time.NewTimer(n.waitTimeout)
+	defer timer.Stop()
+
 	for {
 		select {
-		case <-ctx.Done():
-			//need to use a different context
-			waitForAllRoutinesToFinish(context.TODO(), sem, parallelLimit)
+		case <-timer.C:
 			return fmt.Errorf("timed out (after %s) waiting for nodegroup %q to be drained", n.waitTimeout, n.ng.NameString())
 		default:
 			nodes, err := n.clientSet.CoreV1().Nodes().List(context.TODO(), listOptions)
@@ -136,58 +127,35 @@ func (n *NodeGroupDrainer) Drain() error {
 			}
 
 			if newPendingNodes.Len() == 0 {
-				waitForAllRoutinesToFinish(ctx, sem, parallelLimit)
-				logger.Success("drained all nodes: %v", mapToList(drainedNodes.Items()))
+				logger.Success("drained all nodes: %v", drainedNodes.List())
 				return nil // no new nodes were seen
 			}
 
-			logger.Debug("already drained: %v", mapToList(drainedNodes.Items()))
+			logger.Debug("already drained: %v", drainedNodes.List())
 			logger.Debug("will drain: %v", newPendingNodes.List())
+
 			for i, node := range newPendingNodes.List() {
-				if err := sem.Acquire(ctx, 1); err != nil {
-					logger.Critical("failed to claim sem: %w", err)
+				pending, err := n.evictPods(node)
+				if err != nil {
+					logger.Warning("pod eviction error (%q) on node %s", err, node)
+					time.Sleep(retryDelay)
+					continue
+				}
+				logger.Debug("%d pods to be evicted from %s", pending, node)
+				if pending == 0 {
+					drainedNodes.Insert(node)
 				}
 
-				go func(i int, node string) {
-					defer sem.Release(1)
-					logger.Debug("starting drain of node %s", node)
-					pending, err := n.evictPods(node)
-					if err != nil {
-						logger.Warning("pod eviction error (%q) on node %s", err, node)
-						time.Sleep(retryDelay)
-						return
-					}
-
-					logger.Debug("%d pods to be evicted from %s", pending, node)
-					if pending == 0 {
-						drainedNodes.Set(node, nil)
-					}
-
-					if n.nodeDrainWaitPeriod > 0 {
-						logger.Debug("waiting for %.0f seconds before draining next node", n.nodeDrainWaitPeriod.Seconds())
-						time.Sleep(n.nodeDrainWaitPeriod)
-					}
-				}(i, node)
+				// only wait if we're not on the last node of this iteration
+				if n.nodeDrainWaitPeriod > 0 && i < newPendingNodes.Len()-1 {
+					logger.Debug("waiting for %.0f seconds before draining next node", n.nodeDrainWaitPeriod.Seconds())
+					time.Sleep(n.nodeDrainWaitPeriod)
+				}
 			}
 		}
 	}
 }
 
-func waitForAllRoutinesToFinish(ctx context.Context, sem *semaphore.Weighted, size int64) {
-	if err := sem.Acquire(ctx, size); err != nil {
-		logger.Critical("failed to claim sem: %w", err)
-	}
-}
-
-func mapToList(m map[string]interface{}) []string {
-	list := []string{}
-	for key := range m {
-		list = append(list, key)
-	}
-
-	return list
-}
-
 func (n *NodeGroupDrainer) toggleCordon(cordon bool, nodes *corev1.NodeList) {
 	for _, node := range nodes.Items {
 		c := NewCordonHelper(&node, cordon)
@@ -212,9 +180,6 @@ func (n *NodeGroupDrainer) evictPods(node string) (int, error) {
 	if len(errs) > 0 {
 		return 0, fmt.Errorf("errs: %v", errs) // TODO: improve formatting
 	}
-	if list == nil {
-		return 0, nil
-	}
 	if w := list.Warnings(); w != "" {
 		logger.Warning(w)
 	}