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Address feedback for new /ephemeralcontainers API

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* Use deep copies in `PrepareForUpdate()`
* Preserve select metadata from new pod
* Use patch to add ephemeral container `kubectl debug`
* Distinguish between pod vs /ephemeralcontainers NotFound
This commit is contained in:
Lee Verberne 2021-04-14 18:40:42 +02:00
parent d8ee5ab09e
commit 97726a50c1
4 changed files with 271 additions and 18 deletions
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17
pkg/registry/core/pod/strategy.go
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@ -205,15 +205,22 @@ type podEphemeralContainersStrategy struct {
// EphemeralContainersStrategy wraps and exports the used podStrategy for the storage package.
var EphemeralContainersStrategy = podEphemeralContainersStrategy{Strategy}
// dropNonEphemeralContainerUpdates discards all changes except for pod.Spec.EphemeralContainers and certain metadata
func dropNonEphemeralContainerUpdates(newPod, oldPod *api.Pod) *api.Pod {
pod := oldPod.DeepCopy()
pod.Name = newPod.Name
pod.Namespace = newPod.Namespace
pod.ResourceVersion = newPod.ResourceVersion
pod.UID = newPod.UID
pod.Spec.EphemeralContainers = newPod.Spec.EphemeralContainers
return pod
}
func (podEphemeralContainersStrategy) PrepareForUpdate(ctx context.Context, obj, old runtime.Object) {
newPod := obj.(*api.Pod)
oldPod := old.(*api.Pod)
// Drop all changes except for pod.Spec.EphemeralContainers
ec := newPod.Spec.EphemeralContainers
*newPod = *oldPod
newPod.Spec.EphemeralContainers = ec
*newPod = *dropNonEphemeralContainerUpdates(newPod, oldPod)
podutil.DropDisabledPodFields(newPod, oldPod)
}

219
pkg/registry/core/pod/strategy_test.go
View File

@ -24,6 +24,7 @@ import (
"reflect"
"testing"
"github.com/google/go-cmp/cmp"
"github.com/stretchr/testify/require"
v1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/api/errors"
@ -1381,3 +1382,221 @@ func TestPodStrategyValidateUpdate(t *testing.T) {
})
}
}
func TestDropNonEphemeralContainerUpdates(t *testing.T) {
tests := []struct {
name string
oldPod, newPod, wantPod *api.Pod
}{
{
name: "simple ephemeral container append",
oldPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "test-pod",
Namespace: "test-ns",
ResourceVersion: "1",
},
Spec: api.PodSpec{
Containers: []api.Container{
{
Name: "container",
Image: "image",
},
},
},
},
newPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "test-pod",
Namespace: "test-ns",
ResourceVersion: "1",
},
Spec: api.PodSpec{
Containers: []api.Container{
{
Name: "container",
Image: "image",
},
},
EphemeralContainers: []api.EphemeralContainer{
{
EphemeralContainerCommon: api.EphemeralContainerCommon{
Name: "container",
Image: "image",
},
},
},
},
},
wantPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "test-pod",
Namespace: "test-ns",
ResourceVersion: "1",
},
Spec: api.PodSpec{
Containers: []api.Container{
{
Name: "container",
Image: "image",
},
},
EphemeralContainers: []api.EphemeralContainer{
{
EphemeralContainerCommon: api.EphemeralContainerCommon{
Name: "container",
Image: "image",
},
},
},
},
},
},
{
name: "whoops wrong pod",
oldPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "test-pod",
Namespace: "test-ns",
ResourceVersion: "1",
UID: "blue",
},
},
newPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "new-pod",
Namespace: "new-ns",
ResourceVersion: "1",
UID: "green",
},
},
wantPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "new-pod",
Namespace: "new-ns",
ResourceVersion: "1",
UID: "green",
},
},
},
{
name: "resource conflict during update",
oldPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "test-pod",
Namespace: "test-ns",
ResourceVersion: "2",
UID: "blue",
},
},
newPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "test-pod",
Namespace: "test-ns",
ResourceVersion: "1",
UID: "blue",
},
},
wantPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "test-pod",
Namespace: "test-ns",
ResourceVersion: "1",
UID: "blue",
},
},
},
{
name: "drop non-ephemeral container changes",
oldPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "test-pod",
Namespace: "test-ns",
ResourceVersion: "1",
Annotations: map[string]string{"foo": "bar"},
},
Spec: api.PodSpec{
Containers: []api.Container{
{
Name: "container",
Image: "image",
},
},
},
},
newPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "test-pod",
Namespace: "test-ns",
ResourceVersion: "1",
Annotations: map[string]string{"foo": "bar", "whiz": "pop"},
ClusterName: "milo",
},
Spec: api.PodSpec{
Containers: []api.Container{
{
Name: "container",
Image: "newimage",
},
},
EphemeralContainers: []api.EphemeralContainer{
{
EphemeralContainerCommon: api.EphemeralContainerCommon{
Name: "container1",
Image: "image",
},
},
{
EphemeralContainerCommon: api.EphemeralContainerCommon{
Name: "container2",
Image: "image",
},
},
},
},
Status: api.PodStatus{
Message: "hi.",
},
},
wantPod: &api.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "test-pod",
Namespace: "test-ns",
ResourceVersion: "1",
Annotations: map[string]string{"foo": "bar"},
},
Spec: api.PodSpec{
Containers: []api.Container{
{
Name: "container",
Image: "image",
},
},
EphemeralContainers: []api.EphemeralContainer{
{
EphemeralContainerCommon: api.EphemeralContainerCommon{
Name: "container1",
Image: "image",
},
},
{
EphemeralContainerCommon: api.EphemeralContainerCommon{
Name: "container2",
Image: "image",
},
},
},
},
},
},
}
for _, tc := range tests {
t.Run(tc.name, func(t *testing.T) {
gotPod := dropNonEphemeralContainerUpdates(tc.newPod, tc.oldPod)
if diff := cmp.Diff(tc.wantPod, gotPod); diff != "" {
t.Errorf("unexpected diff when dropping fields (-want, +got):\n%s", diff)
}
})
}
}

33
staging/src/k8s.io/kubectl/pkg/cmd/debug/debug.go
View File

@ -18,6 +18,7 @@ package debug
import (
"context"
"encoding/json"
"fmt"
"time"
@ -31,7 +32,9 @@ import (
"k8s.io/apimachinery/pkg/fields"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apimachinery/pkg/types"
utilrand "k8s.io/apimachinery/pkg/util/rand"
"k8s.io/apimachinery/pkg/util/strategicpatch"
"k8s.io/apimachinery/pkg/watch"
"k8s.io/cli-runtime/pkg/genericclioptions"
"k8s.io/cli-runtime/pkg/resource"
@ -381,20 +384,36 @@ func (o *DebugOptions) visitPod(ctx context.Context, pod *corev1.Pod) (*corev1.P
// debugByEphemeralContainer runs an EphemeralContainer in the target Pod for use as a debug container
func (o *DebugOptions) debugByEphemeralContainer(ctx context.Context, pod *corev1.Pod) (*corev1.Pod, string, error) {
pods := o.podClient.Pods(pod.Namespace)
klog.V(2).Infof("existing ephemeral containers: %v", pod.Spec.EphemeralContainers)
podJS, err := json.Marshal(pod)
if err != nil {
return nil, "", fmt.Errorf("error creating JSON for pod: %v", err)
}
debugContainer := o.generateDebugContainer(pod)
klog.V(2).Infof("new ephemeral container: %#v", debugContainer)
pod.Spec.EphemeralContainers = append(pod.Spec.EphemeralContainers, *debugContainer)
result, err := pods.UpdateEphemeralContainers(ctx, pod.Name, pod, metav1.UpdateOptions{})
debugPod := pod.DeepCopy()
debugPod.Spec.EphemeralContainers = append(debugPod.Spec.EphemeralContainers, *debugContainer)
debugJS, err := json.Marshal(debugPod)
if err != nil {
// The pod has already been fetched at this point, so a NotFound error indicates the ephemeralcontainers subresource wasn't found.
if serr, ok := err.(*errors.StatusError); ok && serr.Status().Reason == metav1.StatusReasonNotFound {
return nil, "", fmt.Errorf("error creating JSON for debug container: %v", err)
}
patch, err := strategicpatch.CreateTwoWayMergePatch(podJS, debugJS, pod)
if err != nil {
return nil, "", fmt.Errorf("error creating patch to add debug container: %v", err)
}
klog.V(2).Infof("generated strategic merge patch for debug container: %s", patch)
pods := o.podClient.Pods(pod.Namespace)
result, err := pods.Patch(ctx, pod.Name, types.StrategicMergePatchType, patch, metav1.PatchOptions{}, "ephemeralcontainers")
if err != nil {
// The apiserver will return a 404 when the EphemeralContainers feature is disabled because the `/ephemeralcontainers` subresource
// is missing. Unlike the 404 returned by a missing pod, the status details will be empty.
if serr, ok := err.(*errors.StatusError); ok && serr.Status().Reason == metav1.StatusReasonNotFound && serr.ErrStatus.Details.Name == "" {
return nil, "", fmt.Errorf("ephemeral containers are disabled for this cluster (error from server: %q).", err)
}
return nil, "", fmt.Errorf("error updating ephemeral containers: %v", err)
return nil, "", err
}
return result, debugContainer.Name, nil

20
test/integration/pods/pods_test.go
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@ -709,8 +709,9 @@ func TestPodEphemeralContainersDisabled(t *testing.T) {
}
pod, err := setUpEphemeralContainers(client.CoreV1().Pods(ns.Name), pod, nil)
if err != nil {
t.Error(err)
t.Fatal(err)
}
defer integration.DeletePodOrErrorf(t, client, ns.Name, pod.Name)
pod.Spec.EphemeralContainers = append(pod.Spec.EphemeralContainers, v1.EphemeralContainer{
EphemeralContainerCommon: v1.EphemeralContainerCommon{
@ -721,11 +722,18 @@ func TestPodEphemeralContainersDisabled(t *testing.T) {
},
})
if _, err := client.CoreV1().Pods(ns.Name).UpdateEphemeralContainers(context.TODO(), pod.Name, pod, metav1.UpdateOptions{}); err == nil {
t.Errorf("got nil error when updating ephemeral containers with feature disabled, wanted %q", metav1.StatusReasonNotFound)
} else if se := err.(*errors.StatusError); se.ErrStatus.Reason != metav1.StatusReasonNotFound {
t.Errorf("got error reason %q when updating ephemeral containers with feature disabled, want %q: %#v", se.ErrStatus.Reason, metav1.StatusReasonNotFound, se)
if _, err = client.CoreV1().Pods(ns.Name).UpdateEphemeralContainers(context.TODO(), pod.Name, pod, metav1.UpdateOptions{}); err == nil {
t.Fatalf("got nil error when updating ephemeral containers with feature disabled, wanted %q", metav1.StatusReasonNotFound)
}
integration.DeletePodOrErrorf(t, client, ns.Name, pod.Name)
se, ok := err.(*errors.StatusError)
if !ok {
t.Fatalf("got error %#v, expected StatusError", err)
}
if se.ErrStatus.Reason != metav1.StatusReasonNotFound {
t.Errorf("got error reason %q when updating ephemeral containers with feature disabled, want %q: %#v", se.ErrStatus.Reason, metav1.StatusReasonNotFound, se)
}
if se.ErrStatus.Details.Name != "" {
t.Errorf("got error details with name %q, want %q: %#v", se.ErrStatus.Details.Name, "", se)
}
}