Merge pull request #27441 from derekwaynecarr/downward_api_node_defaults

Automatic merge from submit-queue

Revert revert of downward api node defaults

Reverts the revert of https://github.com/kubernetes/kubernetes/pull/27439

Fixes #27062

@dchen1107 - who at Google can help debug why this caused issues with GKE infrastructure but not GCE merge queue?

/cc @wojtek-t @piosz @fgrzadkowski @eparis @pmorie

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)
 }