Add pod eviction logic for scheduler preemption

Add Preempt to scheduler interface
Add preemption to the scheduling workflow
Minor changes to the scheduler integration test library

test/e2e/scheduling/predicates.go

@@ -52,6 +52,7 @@ type pausePodConfig struct {
 	NodeName                          string
 	Ports                             []v1.ContainerPort
 	OwnerReferences                   []metav1.OwnerReference
+	PriorityClassName                 string
 }
 
 var _ = SIGDescribe("SchedulerPredicates [Serial]", func() {
@@ -555,8 +556,9 @@ func initPausePod(f *framework.Framework, conf pausePodConfig) *v1.Pod {
 					Ports: conf.Ports,
 				},
 			},
-			Tolerations: conf.Tolerations,
-			NodeName:    conf.NodeName,
+			Tolerations:       conf.Tolerations,
+			NodeName:          conf.NodeName,
+			PriorityClassName: conf.PriorityClassName,
 		},
 	}
 	if conf.Resources != nil {

test/e2e/scheduling/preemption.go

@@ -0,0 +1,128 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+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 scheduling
+
+import (
+	"fmt"
+	"time"
+
+	"k8s.io/api/core/v1"
+	"k8s.io/api/scheduling/v1alpha1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/api/resource"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/kubernetes/test/e2e/framework"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	_ "github.com/stretchr/testify/assert"
+)
+
+var _ = SIGDescribe("SchedulerPreemption [Serial] [Feature:PodPreemption]", func() {
+	var cs clientset.Interface
+	var nodeList *v1.NodeList
+	var ns string
+	f := framework.NewDefaultFramework("sched-preemption")
+
+	lowPriority, mediumPriority, highPriority := int32(1), int32(100), int32(1000)
+	lowPriorityClassName := f.BaseName + "-low-priority"
+	mediumPriorityClassName := f.BaseName + "-medium-priority"
+	highPriorityClassName := f.BaseName + "-high-priority"
+
+	AfterEach(func() {
+	})
+
+	BeforeEach(func() {
+		cs = f.ClientSet
+		ns = f.Namespace.Name
+		nodeList = &v1.NodeList{}
+
+		_, err := f.ClientSet.SchedulingV1alpha1().PriorityClasses().Create(&v1alpha1.PriorityClass{ObjectMeta: metav1.ObjectMeta{Name: highPriorityClassName}, Value: highPriority})
+		Expect(err == nil || errors.IsAlreadyExists(err)).To(Equal(true))
+		_, err = f.ClientSet.SchedulingV1alpha1().PriorityClasses().Create(&v1alpha1.PriorityClass{ObjectMeta: metav1.ObjectMeta{Name: mediumPriorityClassName}, Value: mediumPriority})
+		Expect(err == nil || errors.IsAlreadyExists(err)).To(Equal(true))
+		_, err = f.ClientSet.SchedulingV1alpha1().PriorityClasses().Create(&v1alpha1.PriorityClass{ObjectMeta: metav1.ObjectMeta{Name: lowPriorityClassName}, Value: lowPriority})
+		Expect(err == nil || errors.IsAlreadyExists(err)).To(Equal(true))
+
+		framework.WaitForAllNodesHealthy(cs, time.Minute)
+		masterNodes, nodeList = framework.GetMasterAndWorkerNodesOrDie(cs)
+
+		err = framework.CheckTestingNSDeletedExcept(cs, ns)
+		framework.ExpectNoError(err)
+	})
+
+	// This test verifies that when a higher priority pod is created and no node with
+	// enough resources is found, scheduler preempts a lower priority pod to schedule
+	// the high priority pod.
+	It("validates basic preemption works", func() {
+		var podRes v1.ResourceList
+		// Create one pod per node that uses a lot of the node's resources.
+		By("Create pods that use 60% of node resources.")
+		pods := make([]*v1.Pod, len(nodeList.Items))
+		for i, node := range nodeList.Items {
+			cpuAllocatable, found := node.Status.Allocatable["cpu"]
+			Expect(found).To(Equal(true))
+			milliCPU := cpuAllocatable.MilliValue() * 40 / 100
+			memAllocatable, found := node.Status.Allocatable["memory"]
+			Expect(found).To(Equal(true))
+			memory := memAllocatable.Value() * 60 / 100
+			podRes = v1.ResourceList{}
+			podRes[v1.ResourceCPU] = *resource.NewMilliQuantity(int64(milliCPU), resource.DecimalSI)
+			podRes[v1.ResourceMemory] = *resource.NewQuantity(int64(memory), resource.BinarySI)
+
+			// make the first pod low priority and the rest medium priority.
+			priorityName := mediumPriorityClassName
+			if i == 0 {
+				priorityName = lowPriorityClassName
+			}
+			pods[i] = createPausePod(f, pausePodConfig{
+				Name:              fmt.Sprintf("pod%d-%v", i, priorityName),
+				PriorityClassName: priorityName,
+				Resources: &v1.ResourceRequirements{
+					Requests: podRes,
+				},
+			})
+			framework.Logf("Created pod: %v", pods[i].Name)
+		}
+		By("Wait for pods to be scheduled.")
+		for _, pod := range pods {
+			framework.ExpectNoError(framework.WaitForPodRunningInNamespace(cs, pod))
+		}
+
+		By("Run a high priority pod that use 60% of a node resources.")
+		// Create a high priority pod and make sure it is scheduled.
+		runPausePod(f, pausePodConfig{
+			Name:              "preemptor-pod",
+			PriorityClassName: highPriorityClassName,
+			Resources: &v1.ResourceRequirements{
+				Requests: podRes,
+			},
+		})
+		// Make sure that the lowest priority pod is deleted.
+		preemptedPod, err := cs.CoreV1().Pods(pods[0].Namespace).Get(pods[0].Name, metav1.GetOptions{})
+		podDeleted := (err != nil && errors.IsNotFound(err)) ||
+			(err == nil && preemptedPod.DeletionTimestamp != nil)
+		Expect(podDeleted).To(BeTrue())
+		// Other pods (mid priority ones) should be present.
+		for i := 1; i < len(pods); i++ {
+			livePod, err := cs.CoreV1().Pods(pods[i].Namespace).Get(pods[i].Name, metav1.GetOptions{})
+			framework.ExpectNoError(err)
+			Expect(livePod.DeletionTimestamp).To(BeNil())
+		}
+	})
+})