actually validate semver in node controller rather than prefix checking

pkg/controller/node/nodecontroller.go

@@ -20,7 +20,6 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"strings"
 	"sync"
 	"time"
 
@@ -38,6 +37,7 @@ import (
 	"k8s.io/kubernetes/pkg/types"
 	"k8s.io/kubernetes/pkg/util"
 	"k8s.io/kubernetes/pkg/util/sets"
+	"k8s.io/kubernetes/pkg/version"
 	"k8s.io/kubernetes/pkg/watch"
 )
 
@@ -287,6 +287,8 @@ func (nc *NodeController) getCondition(status *api.NodeStatus, conditionType api
 	return nil
 }
 
+var gracefulDeletionVersion = version.MustParse("v1.1.0")
+
 // maybeDeleteTerminatingPod non-gracefully deletes pods that are terminating
 // that should not be gracefully terminated.
 func (nc *NodeController) maybeDeleteTerminatingPod(obj interface{}) {
@@ -328,7 +330,13 @@ func (nc *NodeController) maybeDeleteTerminatingPod(obj interface{}) {
 	// guarantee backwards compatibility of master API to kubelets with
 	// versions less than 1.1.0
 	node := nodeObj.(*api.Node)
-	if strings.HasPrefix(node.Status.NodeInfo.KubeletVersion, "v1.0") {
+	v, err := version.Parse(node.Status.NodeInfo.KubeletVersion)
+	if err != nil {
+		glog.Infof("couldn't parse verions %q of minion: %v", node.Status.NodeInfo.KubeletVersion, err)
+		nc.forcefullyDeletePod(pod)
+		return
+	}
+	if gracefulDeletionVersion.GT(v) {
 		nc.forcefullyDeletePod(pod)
 		return
 	}

pkg/controller/node/nodecontroller_test.go

@@ -728,6 +728,20 @@ func TestCheckPod(t *testing.T) {
 		{
 			pod: api.Pod{
 				ObjectMeta: api.ObjectMeta{DeletionTimestamp: &unversioned.Time{}},
+				Spec:       api.PodSpec{NodeName: "older"},
+			},
+			prune: true,
+		},
+		{
+			pod: api.Pod{
+				ObjectMeta: api.ObjectMeta{DeletionTimestamp: &unversioned.Time{}},
+				Spec:       api.PodSpec{NodeName: "oldest"},
+			},
+			prune: true,
+		},
+		{
+			pod: api.Pod{
+				ObjectMeta: api.ObjectMeta{DeletionTimestamp: &unversioned.Time{}},
 				Spec:       api.PodSpec{NodeName: ""},
 			},
 			prune: true,
@@ -763,6 +777,26 @@ func TestCheckPod(t *testing.T) {
 			},
 		},
 	})
+	nc.nodeStore.Store.Add(&api.Node{
+		ObjectMeta: api.ObjectMeta{
+			Name: "older",
+		},
+		Status: api.NodeStatus{
+			NodeInfo: api.NodeSystemInfo{
+				KubeletVersion: "v0.21.4",
+			},
+		},
+	})
+	nc.nodeStore.Store.Add(&api.Node{
+		ObjectMeta: api.ObjectMeta{
+			Name: "oldest",
+		},
+		Status: api.NodeStatus{
+			NodeInfo: api.NodeSystemInfo{
+				KubeletVersion: "v0.19.3",
+			},
+		},
+	})
 
 	for i, tc := range tcs {
 		var deleteCalls int