Add a flag to allow to schedule workload to the master node

pkg/kubeadm/api/types.go

@@ -45,6 +45,7 @@ type InitFlags struct {
 		DNSDomain string
 	}
 	CloudProvider string
+	Schedulable bool
 }
 
 const (

pkg/kubeadm/cmd/init.go

@@ -77,6 +77,10 @@ func NewCmdInit(out io.Writer, s *kubeadmapi.KubeadmConfig) *cobra.Command {
 		&s.InitFlags.CloudProvider, "cloud-provider", "",
 		`(optional) enable cloud proiver features (external load-balancers, storage, etc)`,
 	)
+	cmd.PersistentFlags().BoolVar(
+		&s.InitFlags.Schedulable, "schedule-workload", false,
+		`(optional) allow to schedule workload to the node`,
+	)
 
 	return cmd
 }
@@ -135,7 +139,7 @@ func RunInit(out io.Writer, cmd *cobra.Command, args []string, s *kubeadmapi.Kub
 		return err
 	}
 
-	if err := kubemaster.UpdateMasterRoleLabelsAndTaints(client); err != nil {
+	if err := kubemaster.UpdateMasterRoleLabelsAndTaints(client, s.Schedulable); err != nil {
 		return err
 	}
 

pkg/kubeadm/cmd/manual.go

@@ -129,6 +129,10 @@ func NewCmdManualBootstrapInitMaster(out io.Writer, s *kubeadmapi.KubeadmConfig)
 		&s.InitFlags.Services.DNSDomain, "service-dns-domain", "cluster.local",
 		`(optional) use alterantive domain name for services, e.g. "myorg.internal"`,
 	)
+	cmd.PersistentFlags().BoolVar(
+		&s.InitFlags.Schedulable, "schedule-workload", false,
+		`(optional) allow to schedule workload to the node`,
+	)
 
 	return cmd
 }
@@ -181,7 +185,7 @@ func RunManualBootstrapInitMaster(out io.Writer, cmd *cobra.Command, args []stri
 		return err
 	}
 
-	if err := kubemaster.UpdateMasterRoleLabelsAndTaints(client); err != nil {
+	if err := kubemaster.UpdateMasterRoleLabelsAndTaints(client, s.Schedulable); err != nil {
 		return err
 	}
 

pkg/kubeadm/master/apiclient.go

@@ -159,21 +159,24 @@ func findMyself(client *clientset.Clientset) (*api.Node, error) {
 	return node, nil
 }
 
-func attemptToUpdateMasterRoleLabelsAndTaints(client *clientset.Clientset) error {
+func attemptToUpdateMasterRoleLabelsAndTaints(client *clientset.Clientset, schedulable bool) error {
 	n, err := findMyself(client)
 	if err != nil {
 		return err
 	}
 
 	n.ObjectMeta.Labels["kubeadm.alpha.kubernetes.io/role"] = "master"
-	taintsAnnotation, _ := json.Marshal([]api.Taint{{Key: "dedicated", Value: "master", Effect: "NoSchedule"}})
-	n.ObjectMeta.Annotations[api.TaintsAnnotationKey] = string(taintsAnnotation)
+
+	if !schedulable {
+		taintsAnnotation, _ := json.Marshal([]api.Taint{{Key: "dedicated", Value: "master", Effect: "NoSchedule"}})
+		n.ObjectMeta.Annotations[api.TaintsAnnotationKey] = string(taintsAnnotation)
+	}
 
 	if _, err := client.Nodes().Update(n); err != nil {
 		if apierrs.IsConflict(err) {
 			fmt.Println("<master/apiclient> temporarily unable to update master node metadata due to conflict (will retry)")
 			time.Sleep(500 * time.Millisecond)
-			attemptToUpdateMasterRoleLabelsAndTaints(client)
+			attemptToUpdateMasterRoleLabelsAndTaints(client, schedulable)
 		} else {
 			return err
 		}
@@ -182,8 +185,8 @@ func attemptToUpdateMasterRoleLabelsAndTaints(client *clientset.Clientset) error
 	return nil
 }
 
-func UpdateMasterRoleLabelsAndTaints(client *clientset.Clientset) error {
-	err := attemptToUpdateMasterRoleLabelsAndTaints(client)
+func UpdateMasterRoleLabelsAndTaints(client *clientset.Clientset, schedulable bool) error {
+	err := attemptToUpdateMasterRoleLabelsAndTaints(client, schedulable)
 	if err != nil {
 		return fmt.Errorf("<master/apiclient> failed to update master node - %s", err)
 	}