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			288 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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    http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package e2e_node
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import (
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	"fmt"
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	"strconv"
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	"time"
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	"github.com/golang/glog"
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	"k8s.io/apimachinery/pkg/api/resource"
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	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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	"k8s.io/kubernetes/pkg/api/v1"
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	nodeutil "k8s.io/kubernetes/pkg/api/v1/node"
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	"k8s.io/kubernetes/pkg/apis/componentconfig"
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	"k8s.io/kubernetes/test/e2e/framework"
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	. "github.com/onsi/ginkgo"
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	. "github.com/onsi/gomega"
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)
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// Eviction Policy is described here:
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// https://github.com/kubernetes/kubernetes/blob/master/docs/proposals/kubelet-eviction.md
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var _ = framework.KubeDescribe("MemoryEviction [Slow] [Serial] [Disruptive]", func() {
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	const (
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		evictionHard = "memory.available<40%"
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	)
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	f := framework.NewDefaultFramework("eviction-test")
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	// This is a dummy context to wrap the outer AfterEach, which will run after the inner AfterEach.
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	// We want to list all of the node and pod events, including any that occur while waiting for
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	// memory pressure reduction, even if we time out while waiting.
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	Context("", func() {
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		AfterEach(func() {
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			// Print events
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			logNodeEvents(f)
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			logPodEvents(f)
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		})
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		Context("", func() {
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			tempSetCurrentKubeletConfig(f, func(c *componentconfig.KubeletConfiguration) {
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				c.EvictionHard = evictionHard
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			})
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			Context("when there is memory pressure", func() {
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				AfterEach(func() {
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					// Wait for the memory pressure condition to disappear from the node status before continuing.
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					By("waiting for the memory pressure condition on the node to disappear before ending the test.")
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					Eventually(func() error {
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						nodeList, err := f.ClientSet.Core().Nodes().List(metav1.ListOptions{})
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						if err != nil {
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							return fmt.Errorf("tried to get node list but got error: %v", err)
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						}
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						// Assuming that there is only one node, because this is a node e2e test.
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						if len(nodeList.Items) != 1 {
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							return fmt.Errorf("expected 1 node, but see %d. List: %v", len(nodeList.Items), nodeList.Items)
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						}
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						node := nodeList.Items[0]
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						_, pressure := nodeutil.GetNodeCondition(&node.Status, v1.NodeMemoryPressure)
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						if pressure != nil && pressure.Status == v1.ConditionTrue {
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							return fmt.Errorf("node is still reporting memory pressure condition: %s", pressure)
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						}
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						return nil
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					}, 5*time.Minute, 15*time.Second).Should(BeNil())
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					// Check available memory after condition disappears, just in case:
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					// Wait for available memory to decrease to a reasonable level before ending the test.
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					// This helps prevent interference with tests that start immediately after this one.
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					By("waiting for available memory to decrease to a reasonable level before ending the test.")
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					Eventually(func() error {
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						summary, err := getNodeSummary()
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						if err != nil {
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							return err
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						}
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						if summary.Node.Memory.AvailableBytes == nil {
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							return fmt.Errorf("summary.Node.Memory.AvailableBytes was nil, cannot get memory stats.")
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						}
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						if summary.Node.Memory.WorkingSetBytes == nil {
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							return fmt.Errorf("summary.Node.Memory.WorkingSetBytes was nil, cannot get memory stats.")
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						}
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						avail := *summary.Node.Memory.AvailableBytes
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						wset := *summary.Node.Memory.WorkingSetBytes
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						// memory limit = avail + wset
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						limit := avail + wset
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						halflimit := limit / 2
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						// Wait for at least half of memory limit to be available
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						if avail >= halflimit {
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							return nil
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						}
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						return fmt.Errorf("current available memory is: %d bytes. Expected at least %d bytes available.", avail, halflimit)
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					}, 5*time.Minute, 15*time.Second).Should(BeNil())
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					// TODO(mtaufen): 5 minute wait to stop flaky test bleeding while we figure out what is actually going on.
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					//                If related to pressure transition period in eviction manager, probably only need to wait
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					//                just over 30s becasue that is the transition period set for node e2e tests. But since we
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					//                know 5 min works and we don't know if transition period is the problem, wait 5 min for now.
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					time.Sleep(5 * time.Minute)
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					// Finally, try starting a new pod and wait for it to be scheduled and running.
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					// This is the final check to try to prevent interference with subsequent tests.
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					podName := "admit-best-effort-pod"
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					f.PodClient().CreateSync(&v1.Pod{
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						ObjectMeta: metav1.ObjectMeta{
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							Name: podName,
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						},
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						Spec: v1.PodSpec{
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							RestartPolicy: v1.RestartPolicyNever,
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							Containers: []v1.Container{
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								{
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									Image: framework.GetPauseImageNameForHostArch(),
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									Name:  podName,
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								},
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							},
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						},
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					})
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				})
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				It("should evict pods in the correct order (besteffort first, then burstable, then guaranteed)", func() {
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					By("creating a guaranteed pod, a burstable pod, and a besteffort pod.")
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					// A pod is guaranteed only when requests and limits are specified for all the containers and they are equal.
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					guaranteed := getMemhogPod("guaranteed-pod", "guaranteed", v1.ResourceRequirements{
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						Requests: v1.ResourceList{
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							"cpu":    resource.MustParse("100m"),
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							"memory": resource.MustParse("100Mi"),
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						},
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						Limits: v1.ResourceList{
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							"cpu":    resource.MustParse("100m"),
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							"memory": resource.MustParse("100Mi"),
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						}})
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					guaranteed = f.PodClient().CreateSync(guaranteed)
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					glog.Infof("pod created with name: %s", guaranteed.Name)
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					// A pod is burstable if limits and requests do not match across all containers.
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					burstable := getMemhogPod("burstable-pod", "burstable", v1.ResourceRequirements{
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						Requests: v1.ResourceList{
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							"cpu":    resource.MustParse("100m"),
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							"memory": resource.MustParse("100Mi"),
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						}})
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					burstable = f.PodClient().CreateSync(burstable)
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					glog.Infof("pod created with name: %s", burstable.Name)
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					// A pod is besteffort if none of its containers have specified any requests or limits	.
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					besteffort := getMemhogPod("besteffort-pod", "besteffort", v1.ResourceRequirements{})
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					besteffort = f.PodClient().CreateSync(besteffort)
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					glog.Infof("pod created with name: %s", besteffort.Name)
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					// We poll until timeout or all pods are killed.
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					// Inside the func, we check that all pods are in a valid phase with
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					// respect to the eviction order of best effort, then burstable, then guaranteed.
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					By("polling the Status.Phase of each pod and checking for violations of the eviction order.")
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					Eventually(func() error {
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						gteed, gtErr := f.ClientSet.Core().Pods(f.Namespace.Name).Get(guaranteed.Name, metav1.GetOptions{})
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						framework.ExpectNoError(gtErr, fmt.Sprintf("getting pod %s", guaranteed.Name))
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						gteedPh := gteed.Status.Phase
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						burst, buErr := f.ClientSet.Core().Pods(f.Namespace.Name).Get(burstable.Name, metav1.GetOptions{})
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						framework.ExpectNoError(buErr, fmt.Sprintf("getting pod %s", burstable.Name))
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						burstPh := burst.Status.Phase
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						best, beErr := f.ClientSet.Core().Pods(f.Namespace.Name).Get(besteffort.Name, metav1.GetOptions{})
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						framework.ExpectNoError(beErr, fmt.Sprintf("getting pod %s", besteffort.Name))
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						bestPh := best.Status.Phase
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						glog.Infof("pod phase: guaranteed: %v, burstable: %v, besteffort: %v", gteedPh, burstPh, bestPh)
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						// NOTE/TODO(mtaufen): This should help us debug why burstable appears to fail before besteffort in some
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						//                     scenarios. We have seen some evidence that the eviction manager has in fact done the
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						//                     right thing and evicted the besteffort first, and attempted to change the besteffort phase
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						//                     to "Failed" when it evicts it, but that for some reason the test isn't seeing the updated
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						//                     phase. I'm trying to confirm or deny this.
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						//                     The eviction manager starts trying to evict things when the node comes under memory
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						//                     pressure, and the eviction manager reports this information in the pressure condition. If we
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						//                     see the eviction manager reporting a pressure condition for a while without the besteffort failing,
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						//                     and we see that the manager did in fact evict the besteffort (this should be in the Kubelet log), we
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						//                     will have more reason to believe the phase is out of date.
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						nodeList, err := f.ClientSet.Core().Nodes().List(metav1.ListOptions{})
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						if err != nil {
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							glog.Errorf("tried to get node list but got error: %v", err)
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						}
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						if len(nodeList.Items) != 1 {
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							glog.Errorf("expected 1 node, but see %d. List: %v", len(nodeList.Items), nodeList.Items)
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						}
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						node := nodeList.Items[0]
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						_, pressure := nodeutil.GetNodeCondition(&node.Status, v1.NodeMemoryPressure)
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						glog.Infof("node pressure condition: %s", pressure)
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						// NOTE/TODO(mtaufen): Also log (at least temporarily) the actual memory consumption on the node.
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						//                     I used this to plot memory usage from a successful test run and it looks the
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						//                     way I would expect. I want to see what the plot from a flake looks like.
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						summary, err := getNodeSummary()
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						if err != nil {
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							return err
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						}
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						if summary.Node.Memory.WorkingSetBytes != nil {
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							wset := *summary.Node.Memory.WorkingSetBytes
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							glog.Infof("Node's working set is (bytes): %v", wset)
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						}
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						if bestPh == v1.PodRunning {
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							Expect(burstPh).NotTo(Equal(v1.PodFailed), "burstable pod failed before best effort pod")
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							Expect(gteedPh).NotTo(Equal(v1.PodFailed), "guaranteed pod failed before best effort pod")
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						} else if burstPh == v1.PodRunning {
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							Expect(gteedPh).NotTo(Equal(v1.PodFailed), "guaranteed pod failed before burstable pod")
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						}
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						// When both besteffort and burstable have been evicted, the test has completed.
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						if bestPh == v1.PodFailed && burstPh == v1.PodFailed {
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							return nil
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						}
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						return fmt.Errorf("besteffort and burstable have not yet both been evicted.")
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					}, 60*time.Minute, 5*time.Second).Should(BeNil())
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				})
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			})
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		})
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	})
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})
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func getMemhogPod(podName string, ctnName string, res v1.ResourceRequirements) *v1.Pod {
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	env := []v1.EnvVar{
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		{
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			Name: "MEMORY_LIMIT",
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			ValueFrom: &v1.EnvVarSource{
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				ResourceFieldRef: &v1.ResourceFieldSelector{
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					Resource: "limits.memory",
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				},
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			},
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		},
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	}
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	// If there is a limit specified, pass 80% of it for -mem-total, otherwise use the downward API
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	// to pass limits.memory, which will be the total memory available.
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	// This helps prevent a guaranteed pod from triggering an OOM kill due to it's low memory limit,
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	// which will cause the test to fail inappropriately.
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	var memLimit string
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	if limit, ok := res.Limits["memory"]; ok {
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		memLimit = strconv.Itoa(int(
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			float64(limit.Value()) * 0.8))
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	} else {
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		memLimit = "$(MEMORY_LIMIT)"
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	}
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	return &v1.Pod{
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		ObjectMeta: metav1.ObjectMeta{
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			Name: podName,
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		},
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		Spec: v1.PodSpec{
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			RestartPolicy: v1.RestartPolicyNever,
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			Containers: []v1.Container{
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				{
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					Name:            ctnName,
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					Image:           "gcr.io/google-containers/stress:v1",
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					ImagePullPolicy: "Always",
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					Env:             env,
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					// 60 min timeout * 60s / tick per 10s = 360 ticks before timeout => ~11.11Mi/tick
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					// to fill ~4Gi of memory, so initial ballpark 12Mi/tick.
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					// We might see flakes due to timeout if the total memory on the nodes increases.
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					Args:      []string{"-mem-alloc-size", "12Mi", "-mem-alloc-sleep", "10s", "-mem-total", memLimit},
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					Resources: res,
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				},
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			},
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		},
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	}
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}
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