Adds e2e tests for DNS horizontal autoscaling feature

The e2e tests cover cases like cluster size changed, parameters
changed, ConfigMap got deleted, autoscaler pod got deleted, etc.
They are separated into a fast part(could be run parallelly) and
a slow part(put in [serial]). The fast part of the e2e tests cost
around 50 seconds to run.

test/e2e/BUILD

@@ -29,6 +29,7 @@ go_library(
         "deployment.go",
         "disruption.go",
         "dns.go",
+        "dns_autoscaling.go",
         "e2e.go",
         "empty.go",
         "empty_dir_wrapper.go",

test/e2e/dns_autoscaling.go

@@ -0,0 +1,244 @@
+/*
+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"
+	"math"
+	"reflect"
+	"strings"
+	"time"
+
+	"k8s.io/kubernetes/pkg/api"
+	clientset "k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset"
+	"k8s.io/kubernetes/pkg/labels"
+	"k8s.io/kubernetes/pkg/util/wait"
+	"k8s.io/kubernetes/test/e2e/framework"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+const (
+	DNSdefaultTimeout      = 5 * time.Minute
+	DNSscaleUpTimeout      = 5 * time.Minute
+	DNSscaleDownTimeout    = 10 * time.Minute
+	DNSNamespace           = "kube-system"
+	ClusterAddonLabelKey   = "k8s-app"
+	KubeDNSLabelName       = "kube-dns"
+	DNSAutoscalerLabelName = "kube-dns-autoscaler"
+)
+
+var _ = framework.KubeDescribe("DNS horizontal autoscaling", func() {
+	f := framework.NewDefaultFramework("dns-autoscaling")
+	var c clientset.Interface
+	var nodeCount int
+	var previousParams map[string]string
+	DNSParams_1 := map[string]string{"linear": "{\"nodesPerReplica\": 1}"}
+	DNSParams_2 := map[string]string{"linear": "{\"nodesPerReplica\": 2}"}
+	DNSParams_3 := map[string]string{"linear": "{\"nodesPerReplica\": 3}"}
+
+	BeforeEach(func() {
+		framework.SkipUnlessProviderIs("gce")
+		c = f.ClientSet
+
+		nodes := framework.GetReadySchedulableNodesOrDie(c)
+		nodeCount = len(nodes.Items)
+		Expect(nodeCount).NotTo(BeZero())
+
+		pcm, err := fetchDNSScalingConfigMap(c)
+		ExpectNoError(err)
+		previousParams = pcm.Data
+
+		By("Replace the dns autoscaling parameters with testing parameters")
+		ExpectNoError(updateDNSScalingConfigMap(c, packDNSScalingConfigMap(DNSParams_1)))
+		By("Wait for kube-dns scaled to expected number")
+		ExpectNoError(waitForDNSReplicasSatisfied(c, nodeCount, DNSdefaultTimeout))
+	})
+
+	AfterEach(func() {
+		By("Restoring intial dns autoscaling parameters")
+		ExpectNoError(updateDNSScalingConfigMap(c, packDNSScalingConfigMap(previousParams)))
+	})
+
+	// This test is separated because it is slow and need to run serially
+	It("[Serial] [Slow] kube-dns-autoscaler should scale kube-dns pods when cluster size changed", func() {
+		originalSizes := make(map[string]int)
+		sum := 0
+		for _, mig := range strings.Split(framework.TestContext.CloudConfig.NodeInstanceGroup, ",") {
+			size, err := GroupSize(mig)
+			ExpectNoError(err)
+			By(fmt.Sprintf("Initial size of %s: %d", mig, size))
+			originalSizes[mig] = size
+			sum += size
+		}
+		Expect(nodeCount).Should(Equal(sum))
+
+		By("Manually increase cluster size")
+		increasedSize := 0
+		increasedSizes := make(map[string]int)
+		for key, val := range originalSizes {
+			increasedSizes[key] = val + 1
+			increasedSize += increasedSizes[key]
+		}
+		setMigSizes(increasedSizes)
+		ExpectNoError(WaitForClusterSizeFunc(c,
+			func(size int) bool { return size == increasedSize }, DNSscaleUpTimeout))
+		By("Wait for kube-dns scaled to expected number")
+		ExpectNoError(waitForDNSReplicasSatisfied(c, increasedSize, DNSdefaultTimeout))
+
+		By("Restoring cluster size")
+		setMigSizes(originalSizes)
+		framework.ExpectNoError(framework.WaitForClusterSize(c, nodeCount, DNSscaleDownTimeout))
+		By("Wait for kube-dns scaled to expected number")
+		ExpectNoError(waitForDNSReplicasSatisfied(c, nodeCount, DNSdefaultTimeout))
+	})
+
+	It("kube-dns-autoscaler should scale kube-dns pods in both nonfaulty and faulty scenarios", func() {
+
+		By("--- Scenario: should scale kube-dns based on changed parameters ---")
+		By("Replace the dns autoscaling parameters with the second testing parameters")
+		ExpectNoError(updateDNSScalingConfigMap(c, packDNSScalingConfigMap(DNSParams_2)))
+		By("Wait for kube-dns scaled to expected number")
+		ExpectNoError(waitForDNSReplicasSatisfied(c, int(math.Ceil(float64(nodeCount)/2.0)), DNSdefaultTimeout))
+
+		By("--- Scenario: should re-create scaling parameters with default value when parameters got deleted ---")
+		By("Delete the ConfigMap for autoscaler")
+		err := deleteDNSScalingConfigMap(c)
+		ExpectNoError(err)
+
+		By("Wait for the ConfigMap got re-created")
+		configMap, err := waitForDNSConfigMapCreated(c, DNSdefaultTimeout)
+		ExpectNoError(err)
+
+		By("Check the new created ConfigMap got the same data as we have")
+		Expect(reflect.DeepEqual(previousParams, configMap.Data)).To(Equal(true))
+
+		By("Replace the dns autoscaling parameters with the second testing parameters")
+		ExpectNoError(updateDNSScalingConfigMap(c, packDNSScalingConfigMap(DNSParams_2)))
+		By("Wait for kube-dns scaled to expected number")
+		ExpectNoError(waitForDNSReplicasSatisfied(c, int(math.Ceil(float64(nodeCount)/2.0)), DNSdefaultTimeout))
+
+		By("--- Scenario: should recover after autoscaler pod got deleted ---")
+		By("Delete the autoscaler pod for kube-dns")
+		ExpectNoError(deleteDNSAutoscalerPod(c))
+
+		By("Replace the dns autoscaling parameters with the third testing parameters")
+		ExpectNoError(updateDNSScalingConfigMap(c, packDNSScalingConfigMap(DNSParams_3)))
+		By("Wait for kube-dns scaled to expected number")
+		ExpectNoError(waitForDNSReplicasSatisfied(c, int(math.Ceil(float64(nodeCount)/3.0)), DNSdefaultTimeout))
+	})
+})
+
+func fetchDNSScalingConfigMap(c clientset.Interface) (*api.ConfigMap, error) {
+	cm, err := c.Core().ConfigMaps(DNSNamespace).Get(DNSAutoscalerLabelName)
+	if err != nil {
+		return nil, err
+	}
+	return cm, nil
+}
+
+func deleteDNSScalingConfigMap(c clientset.Interface) error {
+	if err := c.Core().ConfigMaps(DNSNamespace).Delete(DNSAutoscalerLabelName, nil); err != nil {
+		return err
+	}
+	framework.Logf("DNS autoscaling ConfigMap deleted.")
+	return nil
+}
+
+func packDNSScalingConfigMap(params map[string]string) *api.ConfigMap {
+	configMap := api.ConfigMap{}
+	configMap.ObjectMeta.Name = DNSAutoscalerLabelName
+	configMap.ObjectMeta.Namespace = DNSNamespace
+	configMap.Data = params
+	return &configMap
+}
+
+func updateDNSScalingConfigMap(c clientset.Interface, configMap *api.ConfigMap) error {
+	_, err := c.Core().ConfigMaps(DNSNamespace).Update(configMap)
+	if err != nil {
+		return err
+	}
+	framework.Logf("DNS autoscaling ConfigMap updated.")
+	return nil
+}
+
+func getDNSReplicas(c clientset.Interface) (int, error) {
+	label := labels.SelectorFromSet(labels.Set(map[string]string{ClusterAddonLabelKey: KubeDNSLabelName}))
+	listOpts := api.ListOptions{LabelSelector: label}
+	rcs, err := c.Core().ReplicationControllers(DNSNamespace).List(listOpts)
+	if err != nil {
+		return 0, err
+	}
+	Expect(len(rcs.Items)).Should(Equal(1))
+
+	rc := rcs.Items[0]
+	return int(rc.Spec.Replicas), nil
+}
+
+func deleteDNSAutoscalerPod(c clientset.Interface) error {
+	label := labels.SelectorFromSet(labels.Set(map[string]string{ClusterAddonLabelKey: DNSAutoscalerLabelName}))
+	listOpts := api.ListOptions{LabelSelector: label}
+	pods, err := c.Core().Pods(DNSNamespace).List(listOpts)
+	if err != nil {
+		return err
+	}
+	Expect(len(pods.Items)).Should(Equal(1))
+
+	podName := pods.Items[0].Name
+	if err := c.Core().Pods(DNSNamespace).Delete(podName, nil); err != nil {
+		return err
+	}
+	framework.Logf("DNS autoscaling pod %v deleted.", podName)
+	return nil
+}
+
+func waitForDNSReplicasSatisfied(c clientset.Interface, expected int, timeout time.Duration) (err error) {
+	var current int
+	framework.Logf("Waiting up to %v for kube-dns reach %v replicas", timeout, expected)
+	condition := func() (bool, error) {
+		current, err = getDNSReplicas(c)
+		if err != nil {
+			return false, err
+		}
+		if current != expected {
+			return false, nil
+		}
+		return true, nil
+	}
+
+	if err = wait.Poll(time.Second, timeout, condition); err != nil {
+		return fmt.Errorf("err waiting for DNS replicas to satisfy %v, got %v: %v", expected, current, err)
+	}
+	return nil
+}
+
+func waitForDNSConfigMapCreated(c clientset.Interface, timeout time.Duration) (configMap *api.ConfigMap, err error) {
+	framework.Logf("Waiting up to %v for DNS autoscaling ConfigMap got re-created", timeout)
+	condition := func() (bool, error) {
+		configMap, err = fetchDNSScalingConfigMap(c)
+		if err != nil {
+			return false, nil
+		}
+		return true, nil
+	}
+
+	if err = wait.Poll(time.Second, timeout, condition); err != nil {
+		return nil, fmt.Errorf("err waiting for DNS autoscaling ConfigMap got re-created: %v", err)
+	}
+	return configMap, nil
+}

test/test_owners.csv

@@ -38,6 +38,8 @@ Container Lifecycle Hook when create a pod with lifecycle hook when it is http h
 Container Runtime Conformance Test container runtime conformance blackbox test when running a container with a new image *,Random-Liu,0
 Container Runtime Conformance Test container runtime conformance blackbox test when starting a container that exits it should run with the expected status,luxas,1
 Container Runtime Conformance Test container runtime conformance blackbox test when starting a container that exits should report termination message if TerminationMessagePath is set,timothysc,1
+DNS horizontal autoscaling kube-dns-autoscaler should scale kube-dns pods in both nonfaulty and faulty scenarios,MrHohn,0
+DNS horizontal autoscaling kube-dns-autoscaler should scale kube-dns pods when cluster size changed,MrHohn,0
 DNS should provide DNS for ExternalName services,rmmh,1
 DNS should provide DNS for pods for Hostname and Subdomain Annotation,mtaufen,1
 DNS should provide DNS for services,roberthbailey,1