Drain nodes in parallel

go.mod

@@ -335,6 +335,7 @@ 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

@@ -1929,6 +1929,8 @@ 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

@@ -319,6 +319,7 @@ 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/cluster/cluster.go

@@ -16,7 +16,7 @@ import (
 
 type Cluster interface {
 	Upgrade(dryRun bool) error
-	Delete(waitInterval time.Duration, wait, force, disableNodegroupEviction bool) error
+	Delete(waitInterval time.Duration, wait, force, disableNodegroupEviction bool, parallel int) error
 }
 
 func New(cfg *api.ClusterConfig, ctl *eks.ClusterProvider) (Cluster, error) {

pkg/actions/cluster/delete.go

@@ -165,7 +165,8 @@ func checkForUndeletedStacks(stackManager manager.StackManager) error {
 	return nil
 }
 
-func drainAllNodeGroups(cfg *api.ClusterConfig, ctl *eks.ClusterProvider, clientSet kubernetes.Interface, allStacks []manager.NodeGroupStack, disableEviction bool, nodeGroupDrainer NodeGroupDrainer, vpcCniDeleter vpcCniDeleter) error {
+func drainAllNodeGroups(cfg *api.ClusterConfig, ctl *eks.ClusterProvider, clientSet kubernetes.Interface, allStacks []manager.NodeGroupStack,
+	disableEviction bool, parallel int, nodeGroupDrainer NodeGroupDrainer, vpcCniDeleter vpcCniDeleter) error {
 	if len(allStacks) == 0 {
 		return nil
 	}
@@ -183,6 +184,7 @@ func drainAllNodeGroups(cfg *api.ClusterConfig, ctl *eks.ClusterProvider, client
 		NodeGroups:      cmdutils.ToKubeNodeGroups(cfg),
 		MaxGracePeriod:  ctl.Provider.WaitTimeout(),
 		DisableEviction: disableEviction,
+		Parallel:        parallel,
 	}
 	if err := nodeGroupDrainer.Drain(drainInput); err != nil {
 		return err

pkg/actions/cluster/owned.go

@@ -69,7 +69,7 @@ func (c *OwnedCluster) Upgrade(dryRun bool) error {
 	return nil
 }
 
-func (c *OwnedCluster) Delete(_ time.Duration, wait, force, disableNodegroupEviction bool) error {
+func (c *OwnedCluster) Delete(_ time.Duration, wait, force, disableNodegroupEviction bool, parallel int) error {
 	var (
 		clientSet kubernetes.Interface
 		oidc      *iamoidc.OpenIDConnectManager
@@ -111,7 +111,7 @@ func (c *OwnedCluster) Delete(_ time.Duration, wait, force, disableNodegroupEvic
 		}
 
 		nodeGroupManager := c.newNodeGroupManager(c.cfg, c.ctl, clientSet)
-		if err := drainAllNodeGroups(c.cfg, c.ctl, clientSet, allStacks, disableNodegroupEviction, nodeGroupManager, attemptVpcCniDeletion); err != nil {
+		if err := drainAllNodeGroups(c.cfg, c.ctl, clientSet, allStacks, disableNodegroupEviction, parallel, nodeGroupManager, attemptVpcCniDeletion); err != nil {
 			if !force {
 				return err
 			}

pkg/actions/cluster/unowned.go

@@ -54,7 +54,7 @@ func (c *UnownedCluster) Upgrade(dryRun bool) error {
 	return nil
 }
 
-func (c *UnownedCluster) Delete(waitInterval time.Duration, wait, force, disableNodegroupEviction bool) error {
+func (c *UnownedCluster) Delete(waitInterval time.Duration, wait, force, disableNodegroupEviction bool, parallel int) error {
 	clusterName := c.cfg.Metadata.Name
 
 	if err := c.checkClusterExists(clusterName); err != nil {
@@ -79,7 +79,7 @@ func (c *UnownedCluster) Delete(waitInterval time.Duration, wait, force, disable
 		}
 
 		nodeGroupManager := c.newNodeGroupManager(c.cfg, c.ctl, clientSet)
-		if err := drainAllNodeGroups(c.cfg, c.ctl, clientSet, allStacks, disableNodegroupEviction, nodeGroupManager, attemptVpcCniDeletion); err != nil {
+		if err := drainAllNodeGroups(c.cfg, c.ctl, clientSet, allStacks, disableNodegroupEviction, parallel, nodeGroupManager, attemptVpcCniDeletion); err != nil {
 			if !force {
 				return err
 			}

pkg/actions/nodegroup/drain.go

@@ -15,12 +15,13 @@ 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)
+			nodeGroupDrainer := drain.NewNodeGroupDrainer(m.clientSet, n, m.ctl.Provider.WaitTimeout(), input.MaxGracePeriod, input.NodeDrainWaitPeriod, input.Undo, input.DisableEviction, input.Parallel)
 			if err := nodeGroupDrainer.Drain(); err != nil {
 				return err
 			}

pkg/ctl/cmdutils/configfile.go

@@ -4,6 +4,7 @@ import (
 	"encoding/csv"
 	"fmt"
 	"reflect"
+	"strconv"
 	"strings"
 
 	"github.com/kris-nova/logger"
@@ -517,8 +518,8 @@ func normalizeBaseNodeGroup(np api.NodePool, cmd *cobra.Command) {
 	}
 }
 
-// NewDeleteNodeGroupLoader will load config or use flags for 'eksctl delete nodegroup'
-func NewDeleteNodeGroupLoader(cmd *Cmd, ng *api.NodeGroup, ngFilter *filter.NodeGroupFilter) ClusterConfigLoader {
+// NewDeleteAndDrainNodeGroupLoader will load config or use flags for 'eksctl delete nodegroup'
+func NewDeleteAndDrainNodeGroupLoader(cmd *Cmd, ng *api.NodeGroup, ngFilter *filter.NodeGroupFilter) ClusterConfigLoader {
 	l := newCommonClusterConfigLoader(cmd)
 
 	l.validateWithConfigFile = func() error {
@@ -546,6 +547,12 @@ func NewDeleteNodeGroupLoader(cmd *Cmd, ng *api.NodeGroup, ngFilter *filter.Node
 			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/cluster.go

@@ -15,22 +15,25 @@ import (
 )
 
 func deleteClusterCmd(cmd *cmdutils.Cmd) {
-	deleteClusterWithRunFunc(cmd, func(cmd *cmdutils.Cmd, force bool, disableNodegroupEviction bool) error {
-		return doDeleteCluster(cmd, force, disableNodegroupEviction)
+	deleteClusterWithRunFunc(cmd, func(cmd *cmdutils.Cmd, force bool, disableNodegroupEviction bool, parallel int) error {
+		return doDeleteCluster(cmd, force, disableNodegroupEviction, parallel)
 	})
 }
 
-func deleteClusterWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd, force bool, disableNodegroupEviction bool) error) {
+func deleteClusterWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd, force bool, disableNodegroupEviction bool, parallel int) error) {
 	cfg := api.NewClusterConfig()
 	cmd.ClusterConfig = cfg
 
 	cmd.SetDescription("cluster", "Delete a cluster", "")
 
-	var force bool
-	var disableNodegroupEviction bool
+	var (
+		force                    bool
+		disableNodegroupEviction bool
+		parallel                 int
+	)
 	cmd.CobraCommand.RunE = func(_ *cobra.Command, args []string) error {
 		cmd.NameArg = cmdutils.GetNameArg(args)
-		return runFunc(cmd, force, disableNodegroupEviction)
+		return runFunc(cmd, force, disableNodegroupEviction, parallel)
 	}
 
 	cmd.FlagSetGroup.InFlagSet("General", func(fs *pflag.FlagSet) {
@@ -41,6 +44,7 @@ func deleteClusterWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd,
 		cmdutils.AddWaitFlag(fs, &cmd.Wait, "deletion of all resources")
 		fs.BoolVar(&force, "force", false, "Force deletion to continue when errors occur")
 		fs.BoolVar(&disableNodegroupEviction, "disable-nodegroup-eviction", false, "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")
 
 		cmdutils.AddConfigFileFlag(fs, &cmd.ClusterConfigFile)
 		cmdutils.AddTimeoutFlag(fs, &cmd.ProviderConfig.WaitTimeout)
@@ -49,7 +53,7 @@ func deleteClusterWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd,
 	cmdutils.AddCommonFlagsForAWS(cmd.FlagSetGroup, &cmd.ProviderConfig, true)
 }
 
-func doDeleteCluster(cmd *cmdutils.Cmd, force bool, disableNodegroupEviction bool) error {
+func doDeleteCluster(cmd *cmdutils.Cmd, force bool, disableNodegroupEviction bool, parallel int) error {
 	if err := cmdutils.NewMetadataLoader(cmd).Load(); err != nil {
 		return err
 	}
@@ -81,5 +85,5 @@ func doDeleteCluster(cmd *cmdutils.Cmd, force bool, disableNodegroupEviction boo
 		return err
 	}
 
-	return cluster.Delete(time.Second*20, cmd.Wait, force, disableNodegroupEviction)
+	return cluster.Delete(time.Second*20, cmd.Wait, force, disableNodegroupEviction, parallel)
 }

pkg/ctl/delete/nodegroup.go

@@ -17,25 +17,30 @@ import (
 )
 
 func deleteNodeGroupCmd(cmd *cmdutils.Cmd) {
-	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)
+	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)
 	})
 }
 
-func deleteNodeGroupWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd, ng *api.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool) error) {
+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) {
 	cfg := api.NewClusterConfig()
 	ng := api.NewNodeGroup()
 	cmd.ClusterConfig = cfg
 
-	var updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool
-	var maxGracePeriod time.Duration
-	var disableEviction bool
+	var (
+		updateAuthConfigMap  bool
+		deleteNodeGroupDrain bool
+		onlyMissing          bool
+		maxGracePeriod       time.Duration
+		disableEviction      bool
+		parallel             int
+	)
 
 	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)
+		return runFunc(cmd, ng, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing, maxGracePeriod, disableEviction, parallel)
 	}
 
 	cmd.FlagSetGroup.InFlagSet("General", func(fs *pflag.FlagSet) {
@@ -52,6 +57,7 @@ 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")
@@ -61,10 +67,10 @@ 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) error {
+func doDeleteNodeGroup(cmd *cmdutils.Cmd, ng *api.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool, parallel int) error {
 	ngFilter := filter.NewNodeGroupFilter()
 
-	if err := cmdutils.NewDeleteNodeGroupLoader(cmd, ng, ngFilter).Load(); err != nil {
+	if err := cmdutils.NewDeleteAndDrainNodeGroupLoader(cmd, ng, ngFilter).Load(); err != nil {
 		return err
 	}
 
@@ -126,6 +132,7 @@ 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) error {
+				deleteNodeGroupWithRunFunc(cmd, func(cmd *cmdutils.Cmd, ng *v1alpha5.NodeGroup, updateAuthConfigMap, deleteNodeGroupDrain, onlyMissing bool, maxGracePeriod time.Duration, disableEviction bool, parallel int) error {
 					Expect(cmd.ClusterConfig.Metadata.Name).To(Equal("clusterName"))
 					Expect(ng.Name).To(Equal("ng"))
 					count++
@@ -52,5 +52,14 @@ 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

@@ -15,26 +15,30 @@ import (
 )
 
 func drainNodeGroupCmd(cmd *cmdutils.Cmd) {
-	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)
+	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)
 	})
 }
 
-func drainNodeGroupWithRunFunc(cmd *cmdutils.Cmd, runFunc func(cmd *cmdutils.Cmd, ng *api.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool) error) {
+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) {
 	cfg := api.NewClusterConfig()
 	ng := api.NewNodeGroup()
 	cmd.ClusterConfig = cfg
 
-	var undo, onlyMissing bool
-	var maxGracePeriod time.Duration
-	var nodeDrainWaitPeriod time.Duration
-	var disableEviction bool
+	var (
+		undo                bool
+		onlyMissing         bool
+		disableEviction     bool
+		parallel            int
+		maxGracePeriod      time.Duration
+		nodeDrainWaitPeriod time.Duration
+	)
 
 	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)
+		return runFunc(cmd, ng, undo, onlyMissing, maxGracePeriod, nodeDrainWaitPeriod, disableEviction, parallel)
 	}
 
 	cmd.FlagSetGroup.InFlagSet("General", func(fs *pflag.FlagSet) {
@@ -52,15 +56,16 @@ 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) error {
+func doDrainNodeGroup(cmd *cmdutils.Cmd, ng *api.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool, parallel int) error {
 	ngFilter := filter.NewNodeGroupFilter()
 
-	if err := cmdutils.NewDeleteNodeGroupLoader(cmd, ng, ngFilter).Load(); err != nil {
+	if err := cmdutils.NewDeleteAndDrainNodeGroupLoader(cmd, ng, ngFilter).Load(); err != nil {
 		return err
 	}
 
@@ -126,6 +131,7 @@ 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) error {
+				drainNodeGroupWithRunFunc(cmd, func(cmd *cmdutils.Cmd, ng *v1alpha5.NodeGroup, undo, onlyMissing bool, maxGracePeriod, nodeDrainWaitPeriod time.Duration, disableEviction bool, parallel int) error {
 					Expect(cmd.ClusterConfig.Metadata.Name).To(Equal("clusterName"))
 					Expect(ng.Name).To(Equal("ng"))
 					count++
@@ -54,5 +54,13 @@ 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"),
+		}),
 	)
 })