Add UID precondition to kubelet pod status patch updates

pkg/kubelet/status/status_manager.go

@@ -24,7 +24,7 @@ import (
 
 	clientset "k8s.io/client-go/kubernetes"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	apiequality "k8s.io/apimachinery/pkg/api/equality"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -540,7 +540,7 @@ func (m *manager) syncPod(uid types.UID, status versionedPodStatus) {
 	}
 
 	oldStatus := pod.Status.DeepCopy()
-	newPod, patchBytes, err := statusutil.PatchPodStatus(m.kubeClient, pod.Namespace, pod.Name, *oldStatus, mergePodStatus(*oldStatus, status.status))
+	newPod, patchBytes, err := statusutil.PatchPodStatus(m.kubeClient, pod.Namespace, pod.Name, pod.UID, *oldStatus, mergePodStatus(*oldStatus, status.status))
 	klog.V(3).Infof("Patch status for pod %q with %q", format.Pod(pod), patchBytes)
 	if err != nil {
 		klog.Warningf("Failed to update status for pod %q: %v", format.Pod(pod), err)

pkg/util/pod/BUILD

@@ -7,6 +7,7 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//staging/src/k8s.io/api/core/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/strategicpatch:go_default_library",
         "//staging/src/k8s.io/client-go/kubernetes:go_default_library",
@@ -20,6 +21,7 @@ go_test(
     deps = [
         "//staging/src/k8s.io/api/core/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
         "//staging/src/k8s.io/client-go/kubernetes/fake:go_default_library",
     ],
 )

pkg/util/pod/pod.go

@@ -20,15 +20,16 @@ import (
 	"encoding/json"
 	"fmt"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/strategicpatch"
 	clientset "k8s.io/client-go/kubernetes"
 )
 
 // PatchPodStatus patches pod status.
-func PatchPodStatus(c clientset.Interface, namespace, name string, oldPodStatus, newPodStatus v1.PodStatus) (*v1.Pod, []byte, error) {
+func PatchPodStatus(c clientset.Interface, namespace, name string, uid types.UID, oldPodStatus, newPodStatus v1.PodStatus) (*v1.Pod, []byte, error) {
-	patchBytes, err := preparePatchBytesForPodStatus(namespace, name, oldPodStatus, newPodStatus)
+	patchBytes, err := preparePatchBytesForPodStatus(namespace, name, uid, oldPodStatus, newPodStatus)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -40,7 +41,7 @@ func PatchPodStatus(c clientset.Interface, namespace, name string, oldPodStatus,
 	return updatedPod, patchBytes, nil
 }
 
-func preparePatchBytesForPodStatus(namespace, name string, oldPodStatus, newPodStatus v1.PodStatus) ([]byte, error) {
+func preparePatchBytesForPodStatus(namespace, name string, uid types.UID, oldPodStatus, newPodStatus v1.PodStatus) ([]byte, error) {
 	oldData, err := json.Marshal(v1.Pod{
 		Status: oldPodStatus,
 	})
@@ -49,7 +50,8 @@ func preparePatchBytesForPodStatus(namespace, name string, oldPodStatus, newPodS
 	}
 
 	newData, err := json.Marshal(v1.Pod{
-		Status: newPodStatus,
+		ObjectMeta: metav1.ObjectMeta{UID: uid}, // only put the uid in the new object to ensure it appears in the patch as a precondition
+		Status:     newPodStatus,
 	})
 	if err != nil {
 		return nil, fmt.Errorf("failed to Marshal newData for pod %q/%q: %v", namespace, name, err)

pkg/util/pod/pod_test.go

@@ -17,18 +17,21 @@ limitations under the License.
 package pod
 
 import (
+	"fmt"
 	"testing"
 
-	"fmt"
-	"k8s.io/api/core/v1"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/client-go/kubernetes/fake"
 	"reflect"
+
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/client-go/kubernetes/fake"
 )
 
 func TestPatchPodStatus(t *testing.T) {
 	ns := "ns"
 	name := "name"
+	uid := types.UID("myuid")
 	client := &fake.Clientset{}
 	client.CoreV1().Pods(ns).Create(&v1.Pod{
 		ObjectMeta: metav1.ObjectMeta{
@@ -45,7 +48,7 @@ func TestPatchPodStatus(t *testing.T) {
 		{
 			"no change",
 			func(input v1.PodStatus) v1.PodStatus { return input },
-			[]byte(fmt.Sprintf(`{}`)),
+			[]byte(fmt.Sprintf(`{"metadata":{"uid":"myuid"}}`)),
 		},
 		{
 			"message change",
@@ -53,7 +56,7 @@ func TestPatchPodStatus(t *testing.T) {
 				input.Message = "random message"
 				return input
 			},
-			[]byte(fmt.Sprintf(`{"status":{"message":"random message"}}`)),
+			[]byte(fmt.Sprintf(`{"metadata":{"uid":"myuid"},"status":{"message":"random message"}}`)),
 		},
 		{
 			"pod condition change",
@@ -61,7 +64,7 @@ func TestPatchPodStatus(t *testing.T) {
 				input.Conditions[0].Status = v1.ConditionFalse
 				return input
 			},
-			[]byte(fmt.Sprintf(`{"status":{"$setElementOrder/conditions":[{"type":"Ready"},{"type":"PodScheduled"}],"conditions":[{"status":"False","type":"Ready"}]}}`)),
+			[]byte(fmt.Sprintf(`{"metadata":{"uid":"myuid"},"status":{"$setElementOrder/conditions":[{"type":"Ready"},{"type":"PodScheduled"}],"conditions":[{"status":"False","type":"Ready"}]}}`)),
 		},
 		{
 			"additional init container condition",
@@ -74,11 +77,11 @@ func TestPatchPodStatus(t *testing.T) {
 				}
 				return input
 			},
-			[]byte(fmt.Sprintf(`{"status":{"initContainerStatuses":[{"image":"","imageID":"","lastState":{},"name":"init-container","ready":true,"restartCount":0,"state":{}}]}}`)),
+			[]byte(fmt.Sprintf(`{"metadata":{"uid":"myuid"},"status":{"initContainerStatuses":[{"image":"","imageID":"","lastState":{},"name":"init-container","ready":true,"restartCount":0,"state":{}}]}}`)),
 		},
 	}
 	for _, tc := range testCases {
-		_, patchBytes, err := PatchPodStatus(client, ns, name, getPodStatus(), tc.mutate(getPodStatus()))
+		_, patchBytes, err := PatchPodStatus(client, ns, name, uid, getPodStatus(), tc.mutate(getPodStatus()))
 		if err != nil {
 			t.Errorf("unexpected error: %v", err)
 		}