e2e test for rescheduling critical pods

test/e2e/rescheduler.go

+/*
+Copyright 2016 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 e2e
+
+import (
+	"fmt"
+	"time"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/labels"
+	"k8s.io/kubernetes/test/e2e/framework"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+// This test requires Rescheduler to be enabled.
+var _ = framework.KubeDescribe("Rescheduler [Feature:Rescheduler]", func() {
+	f := framework.NewDefaultFramework("rescheduler")
+	var ns string
+	var totalMillicores int
+
+	BeforeEach(func() {
+		ns = f.Namespace.Name
+		nodes := framework.GetReadySchedulableNodesOrDie(f.Client)
+		nodeCount := len(nodes.Items)
+		Expect(nodeCount).NotTo(BeZero())
+
+		cpu := nodes.Items[0].Status.Capacity[api.ResourceCPU]
+		totalMillicores = int((&cpu).MilliValue()) * nodeCount
+	})
+
+	It("should ensure that critical pod is scheduled in case there is no resources available", func() {
+		By("reserving all available cpu")
+		err := reserveAllCpu(f, "reserve-all-cpu", totalMillicores)
+		defer framework.DeleteRCAndPods(f.Client, ns, "reserve-all-cpu")
+		framework.ExpectNoError(err)
+
+		By("creating a new instance of DNS and waiting for DNS to be scheduled")
+		label := labels.SelectorFromSet(labels.Set(map[string]string{"k8s-app": "kube-dns"}))
+		listOpts := api.ListOptions{LabelSelector: label}
+		rcs, err := f.Client.ReplicationControllers(api.NamespaceSystem).List(listOpts)
+		framework.ExpectNoError(err)
+		Expect(len(rcs.Items)).Should(Equal(1))
+
+		rc := rcs.Items[0]
+		replicas := uint(rc.Spec.Replicas)
+
+		err = framework.ScaleRC(f.Client, api.NamespaceSystem, rc.Name, replicas+1, true)
+		defer framework.ExpectNoError(framework.ScaleRC(f.Client, api.NamespaceSystem, rc.Name, replicas, true))
+		framework.ExpectNoError(err)
+	})
+})
+
+func reserveAllCpu(f *framework.Framework, id string, millicores int) error {
+	timeout := 5 * time.Minute
+	replicas := millicores / 100
+
+	ReserveCpu(f, id, 1, 100)
+	framework.ExpectNoError(framework.ScaleRC(f.Client, f.Namespace.Name, id, uint(replicas), false))
+
+	for start := time.Now(); time.Since(start) < timeout; time.Sleep(10 * time.Second) {
+		pods, err := framework.GetPodsInNamespace(f.Client, f.Namespace.Name, framework.ImagePullerLabels)
+		if err != nil {
+			return err
+		}
+
+		if len(pods) != replicas {
+			continue
+		}
+
+		allRunningOrUnschedulable := true
+		for _, pod := range pods {
+			if !podRunningOrUnschedulable(pod) {
+				allRunningOrUnschedulable = false
+				break
+			}
+		}
+		if allRunningOrUnschedulable {
+			return nil
+		}
+	}
+	return fmt.Errorf("Pod name %s: Gave up waiting %v for %d pods to come up", id, timeout, replicas)
+}
+
+func podRunningOrUnschedulable(pod *api.Pod) bool {
+	_, cond := api.GetPodCondition(&pod.Status, api.PodScheduled)
+	if cond != nil && cond.Status == api.ConditionFalse && cond.Reason == "Unschedulable" {
+		return true
+	}
+	running, _ := framework.PodRunningReady(pod)
+	return running
+}