Merge pull request #49129 from justinsb/revert_48056

Automatic merge from submit-queue (batch tested with PRs 49129, 50436, 50417, 50553, 47587)

Revert "Remove old node role label that is not used by kubeadm"

Revert the commit that removed printing of node roles from kubectl.

It sounds like we also need to update the labels we inspect, as these were previously removed.  But starting with a clean revert.

Issue #49124

```release-note
NONE
```

pkg/printers/internalversion/printers.go

@@ -41,6 +41,7 @@ import (
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	"k8s.io/kubernetes/federation/apis/federation"
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/events"
@@ -1156,6 +1157,10 @@ func printNode(obj *api.Node, options printers.PrintOptions) ([]metav1alpha1.Tab
 	if obj.Spec.Unschedulable {
 		status = append(status, "SchedulingDisabled")
 	}
+	role := findNodeRole(obj)
+	if role != "" {
+		status = append(status, role)
+	}
 
 	row.Cells = append(row.Cells, obj.Name, strings.Join(status, ","), translateTimestamp(obj.CreationTimestamp), obj.Status.NodeInfo.KubeletVersion)
 	if options.Wide {
@@ -1186,6 +1191,19 @@ func getNodeExternalIP(node *api.Node) string {
 	return "<none>"
 }
 
+// findNodeRole returns the role of a given node, or "" if none found.
+// The role is determined by looking in order for:
+// * a kubernetes.io/role label
+// * a kubeadm.alpha.kubernetes.io/role label
+// If no role is found, ("", nil) is returned
+func findNodeRole(node *api.Node) string {
+	if role := node.Labels[kubeadm.NodeLabelKubeadmAlphaRole]; role != "" {
+		return role
+	}
+	// No role found
+	return ""
+}
+
 func printNodeList(list *api.NodeList, options printers.PrintOptions) ([]metav1alpha1.TableRow, error) {
 	rows := make([]metav1alpha1.TableRow, 0, len(list.Items))
 	for i := range list.Items {