Merge pull request #27303 from derekwaynecarr/downward_api_node_defaults

Automatic merge from submit-queue

Downward api node defaults

Fixes #27062

Replaces https://github.com/kubernetes/kubernetes/pull/27107

pkg/fieldpath/fieldpath_test.go

@@ -20,7 +20,10 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+
 	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/resource"
 )
 
 func TestExtractFieldPathAsString(t *testing.T) {
@@ -115,3 +118,119 @@ func TestExtractFieldPathAsString(t *testing.T) {
 		}
 	}
 }
+
+func getPod(cname, cpuRequest, cpuLimit, memoryRequest, memoryLimit string) *api.Pod {
+	resources := api.ResourceRequirements{
+		Limits:   make(api.ResourceList),
+		Requests: make(api.ResourceList),
+	}
+	if cpuLimit != "" {
+		resources.Limits[api.ResourceCPU] = resource.MustParse(cpuLimit)
+	}
+	if memoryLimit != "" {
+		resources.Limits[api.ResourceMemory] = resource.MustParse(memoryLimit)
+	}
+	if cpuRequest != "" {
+		resources.Requests[api.ResourceCPU] = resource.MustParse(cpuRequest)
+	}
+	if memoryRequest != "" {
+		resources.Requests[api.ResourceMemory] = resource.MustParse(memoryRequest)
+	}
+	return &api.Pod{
+		Spec: api.PodSpec{
+			Containers: []api.Container{
+				{
+					Name:      cname,
+					Resources: resources,
+				},
+			},
+		},
+	}
+}
+
+func TestExtractResourceValue(t *testing.T) {
+	cases := []struct {
+		fs            *api.ResourceFieldSelector
+		pod           *api.Pod
+		cName         string
+		expectedValue string
+		expectedError error
+	}{
+		{
+			fs: &api.ResourceFieldSelector{
+				Resource: "limits.cpu",
+			},
+			cName:         "foo",
+			pod:           getPod("foo", "", "9", "", ""),
+			expectedValue: "9",
+		},
+		{
+			fs: &api.ResourceFieldSelector{
+				Resource: "requests.cpu",
+			},
+			cName:         "foo",
+			pod:           getPod("foo", "", "", "", ""),
+			expectedValue: "0",
+		},
+		{
+			fs: &api.ResourceFieldSelector{
+				Resource: "requests.cpu",
+			},
+			cName:         "foo",
+			pod:           getPod("foo", "8", "", "", ""),
+			expectedValue: "8",
+		},
+		{
+			fs: &api.ResourceFieldSelector{
+				Resource: "requests.cpu",
+			},
+			cName:         "foo",
+			pod:           getPod("foo", "100m", "", "", ""),
+			expectedValue: "1",
+		},
+		{
+			fs: &api.ResourceFieldSelector{
+				Resource: "requests.cpu",
+				Divisor:  resource.MustParse("100m"),
+			},
+			cName:         "foo",
+			pod:           getPod("foo", "1200m", "", "", ""),
+			expectedValue: "12",
+		},
+		{
+			fs: &api.ResourceFieldSelector{
+				Resource: "requests.memory",
+			},
+			cName:         "foo",
+			pod:           getPod("foo", "", "", "100Mi", ""),
+			expectedValue: "104857600",
+		},
+		{
+			fs: &api.ResourceFieldSelector{
+				Resource: "requests.memory",
+				Divisor:  resource.MustParse("1Mi"),
+			},
+			cName:         "foo",
+			pod:           getPod("foo", "", "", "100Mi", "1Gi"),
+			expectedValue: "100",
+		},
+		{
+			fs: &api.ResourceFieldSelector{
+				Resource: "limits.memory",
+			},
+			cName:         "foo",
+			pod:           getPod("foo", "", "", "10Mi", "100Mi"),
+			expectedValue: "104857600",
+		},
+	}
+	as := assert.New(t)
+	for idx, tc := range cases {
+		actual, err := ExtractResourceValueByContainerName(tc.fs, tc.pod, tc.cName)
+		if tc.expectedError != nil {
+			as.Equal(tc.expectedError, err, "expected test case [%d] to fail with error %v; got %v", idx, tc.expectedError, err)
+		} else {
+			as.Nil(err, "expected test case [%d] to not return an error; got %v", idx, err)
+			as.Equal(tc.expectedValue, actual, "expected test case [%d] to return %q; got %q instead", idx, tc.expectedValue, actual)
+		}
+	}
+}

pkg/kubelet/kubelet.go

@@ -831,6 +831,9 @@ type Kubelet struct {
 	// should manage attachment/detachment of volumes scheduled to this node,
 	// and disable kubelet from executing any attach/detach operations
 	enableControllerAttachDetach bool
+
+	// lastUpdatedNodeObject is a cached version of the node as last reported back to the api server.
+	lastUpdatedNodeObject atomic.Value
 }
 
 // Validate given node IP belongs to the current host
@@ -1143,6 +1146,10 @@ func (kl *Kubelet) registerWithApiserver() {
 			glog.Errorf("Unable to construct api.Node object for kubelet: %v", err)
 			continue
 		}
+
+		// Cache the node object.
+		kl.lastUpdatedNodeObject.Store(node)
+
 		glog.V(2).Infof("Attempting to register node %s", node.Name)
 		if _, err := kl.kubeClient.Core().Nodes().Create(node); err != nil {
 			if !apierrors.IsAlreadyExists(err) {
@@ -1554,7 +1561,11 @@ func (kl *Kubelet) makeEnvironmentVariables(pod *api.Pod, container *api.Contain
 					return result, err
 				}
 			case envVar.ValueFrom.ResourceFieldRef != nil:
-				runtimeVal, err = containerResourceRuntimeValue(envVar.ValueFrom.ResourceFieldRef, pod, container)
+				defaultedPod, defaultedContainer, err := kl.defaultPodLimitsForDownwardApi(pod, container)
+				if err != nil {
+					return result, err
+				}
+				runtimeVal, err = containerResourceRuntimeValue(envVar.ValueFrom.ResourceFieldRef, defaultedPod, defaultedContainer)
 				if err != nil {
 					return result, err
 				}
@@ -1894,7 +1905,12 @@ func (kl *Kubelet) syncPod(o syncPodOptions) error {
 	}
 
 	// Mount volumes and update the volume manager
-	podVolumes, err := kl.mountExternalVolumes(pod)
+	// Default limits for containers here to have downward API expose user-friendly limits to pods.
+	defaultedPod, _, err := kl.defaultPodLimitsForDownwardApi(pod, nil)
+	if err != nil {
+		return err
+	}
+	podVolumes, err := kl.mountExternalVolumes(defaultedPod)
 	if err != nil {
 		ref, errGetRef := api.GetReference(pod)
 		if errGetRef == nil && ref != nil {
@@ -3507,6 +3523,10 @@ func (kl *Kubelet) tryUpdateNodeStatus() error {
 	}
 	// Update the current status on the API server
 	_, err = kl.kubeClient.Core().Nodes().UpdateStatus(node)
+	if err == nil {
+		// store recently updated node information.
+		kl.lastUpdatedNodeObject.Store(node)
+	}
 	return err
 }
 

pkg/kubelet/kubelet_resources.go

@@ -0,0 +1,84 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubelet
+
+import (
+	"fmt"
+
+	"k8s.io/kubernetes/pkg/api"
+)
+
+// defaultPodLimitsForDownwardApi copies the input pod, and optional container,
+// and applies default resource limits. it returns a copy of the input pod,
+// and a copy of the input container (if specified) with default limits
+// applied. if a container has no limit specified, it will default the limit to
+// the node capacity.
+// TODO: if/when we have pod level resources, we need to update this function
+// to use those limits instead of node capacity.
+func (kl *Kubelet) defaultPodLimitsForDownwardApi(pod *api.Pod, container *api.Container) (*api.Pod, *api.Container, error) {
+	if pod == nil {
+		return nil, nil, fmt.Errorf("invalid input, pod cannot be nil")
+	}
+
+	lastUpdatedNodeObject := kl.lastUpdatedNodeObject.Load()
+	if lastUpdatedNodeObject == nil {
+		return nil, nil, fmt.Errorf("failed to find node object in cache, expected a non-nil object in the cache.")
+	}
+	capacity := lastUpdatedNodeObject.(*api.Node).Status.Capacity
+
+	podCopy, err := api.Scheme.Copy(pod)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to perform a deep copy of pod object: %v", err)
+	}
+	outputPod, ok := podCopy.(*api.Pod)
+	if !ok {
+		return nil, nil, fmt.Errorf("unexpected type")
+	}
+	for idx := range outputPod.Spec.Containers {
+		mergeContainerResourceLimitsWithCapacity(&outputPod.Spec.Containers[idx], capacity)
+	}
+
+	var outputContainer *api.Container
+	if container != nil {
+		containerCopy, err := api.Scheme.DeepCopy(container)
+		if err != nil {
+			return nil, nil, fmt.Errorf("failed to perform a deep copy of container object: %v", err)
+		}
+		outputContainer, ok = containerCopy.(*api.Container)
+		if !ok {
+			return nil, nil, fmt.Errorf("unexpected type")
+		}
+		mergeContainerResourceLimitsWithCapacity(outputContainer, capacity)
+	}
+	return outputPod, outputContainer, nil
+}
+
+// mergeContainerResourceLimitsWithCapacity checks if a limit is applied for
+// the container, and if not, it sets the limit based on the capacity.
+func mergeContainerResourceLimitsWithCapacity(container *api.Container,
+	capacity api.ResourceList) {
+	if container.Resources.Limits == nil {
+		container.Resources.Limits = make(api.ResourceList)
+	}
+	for _, resource := range []api.ResourceName{api.ResourceCPU, api.ResourceMemory} {
+		if quantity, exists := container.Resources.Limits[resource]; !exists || quantity.IsZero() {
+			if cap, exists := capacity[resource]; exists {
+				container.Resources.Limits[resource] = *cap.Copy()
+			}
+		}
+	}
+}

pkg/kubelet/kubelet_resources_test.go

@@ -0,0 +1,89 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubelet
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/resource"
+)
+
+func TestPodResourceLimitsDefaulting(t *testing.T) {
+	tk := newTestKubelet(t)
+	node := &api.Node{
+		Status: api.NodeStatus{
+			Capacity: api.ResourceList{
+				api.ResourceCPU:    resource.MustParse("10"),
+				api.ResourceMemory: resource.MustParse("10Gi"),
+			},
+		},
+	}
+	tk.kubelet.lastUpdatedNodeObject.Store(node)
+	cases := []struct {
+		pod      *api.Pod
+		expected *api.Pod
+	}{
+		{
+			pod:      getPod("0", "0"),
+			expected: getPod("10", "10Gi"),
+		},
+		{
+			pod:      getPod("1", "0"),
+			expected: getPod("1", "10Gi"),
+		},
+		{
+			pod:      getPod("", ""),
+			expected: getPod("10", "10Gi"),
+		},
+		{
+			pod:      getPod("0", "1Mi"),
+			expected: getPod("10", "1Mi"),
+		},
+	}
+	as := assert.New(t)
+	for idx, tc := range cases {
+		actual, _, err := tk.kubelet.defaultPodLimitsForDownwardApi(tc.pod, nil)
+		as.Nil(err, "failed to default pod limits: %v", err)
+		as.Equal(tc.expected, actual, "test case [%d] failed. Expected: %+v, Got: %+v", idx, tc.expected, actual)
+	}
+}
+
+func getPod(cpuLimit, memoryLimit string) *api.Pod {
+	resources := api.ResourceRequirements{}
+	if cpuLimit != "" || memoryLimit != "" {
+		resources.Limits = make(api.ResourceList)
+	}
+	if cpuLimit != "" {
+		resources.Limits[api.ResourceCPU] = resource.MustParse(cpuLimit)
+	}
+	if memoryLimit != "" {
+		resources.Limits[api.ResourceMemory] = resource.MustParse(memoryLimit)
+	}
+	return &api.Pod{
+		Spec: api.PodSpec{
+			Containers: []api.Container{
+				{
+					Name:      "foo",
+					Resources: resources,
+				},
+			},
+		},
+	}
+}

pkg/kubelet/kubelet_test.go

@@ -278,7 +278,7 @@ func newTestKubeletWithImageList(t *testing.T, imageList []kubecontainer.Image)
 	}
 	kubelet.evictionManager = evictionManager
 	kubelet.AddPodAdmitHandler(evictionAdmitHandler)
-
+	kubelet.lastUpdatedNodeObject.Store(&api.Node{})
 	return &TestKubelet{kubelet, fakeRuntime, mockCadvisor, fakeKubeClient, fakeMirrorClient, fakeClock, nil}
 }
 

test/e2e/downward_api.go

@@ -128,6 +128,50 @@ var _ = framework.KubeDescribe("Downward API", func() {
 		testDownwardAPI(f, podName, env, expectations)
 	})
 
+	It("should provide default limits.cpu/memory from node capacity", func() {
+		podName := "downward-api-" + string(util.NewUUID())
+		env := []api.EnvVar{
+			{
+				Name: "CPU_LIMIT",
+				ValueFrom: &api.EnvVarSource{
+					ResourceFieldRef: &api.ResourceFieldSelector{
+						Resource: "limits.cpu",
+					},
+				},
+			},
+			{
+				Name: "MEMORY_LIMIT",
+				ValueFrom: &api.EnvVarSource{
+					ResourceFieldRef: &api.ResourceFieldSelector{
+						Resource: "limits.memory",
+					},
+				},
+			},
+		}
+		expectations := []string{
+			fmt.Sprintf("CPU_LIMIT=[1-9]"),
+			fmt.Sprintf("MEMORY_LIMIT=[1-9]"),
+		}
+		pod := &api.Pod{
+			ObjectMeta: api.ObjectMeta{
+				Name:   podName,
+				Labels: map[string]string{"name": podName},
+			},
+			Spec: api.PodSpec{
+				Containers: []api.Container{
+					{
+						Name:    "dapi-container",
+						Image:   "gcr.io/google_containers/busybox:1.24",
+						Command: []string{"sh", "-c", "env"},
+						Env:     env,
+					},
+				},
+				RestartPolicy: api.RestartPolicyNever,
+			},
+		}
+
+		testDownwardAPIUsingPod(f, pod, env, expectations)
+	})
 })
 
 func testDownwardAPI(f *framework.Framework, podName string, env []api.EnvVar, expectations []string) {
@@ -159,5 +203,9 @@ func testDownwardAPI(f *framework.Framework, podName string, env []api.EnvVar, e
 		},
 	}
 
+	testDownwardAPIUsingPod(f, pod, env, expectations)
+}
+
+func testDownwardAPIUsingPod(f *framework.Framework, pod *api.Pod, env []api.EnvVar, expectations []string) {
 	f.TestContainerOutputRegexp("downward api env vars", pod, 0, expectations)
 }