Merge pull request #33239 from MrHohn/dns-autoscaler

Automatic merge from submit-queue

Deploy kube-dns with cluster-proportional-autoscaler

This PR integrates [cluster-proportional-autoscaler](https://github.com/kubernetes-incubator/cluster-proportional-autoscaler) with kube-dns for DNS horizontal autoscaling. 

Fixes #28648 and #27781.

cluster/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml

@@ -0,0 +1,50 @@
+# 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.
+
+apiVersion: extensions/v1beta1
+kind: Deployment
+metadata:
+  name: kube-dns-autoscaler
+  namespace: kube-system
+  labels:
+    k8s-app: kube-dns-autoscaler
+    kubernetes.io/cluster-service: "true"
+spec:
+  template:
+    metadata:
+      labels:
+        k8s-app: kube-dns-autoscaler
+      annotations:
+        scheduler.alpha.kubernetes.io/critical-pod: ''
+        scheduler.alpha.kubernetes.io/tolerations: '[{"key":"CriticalAddonsOnly", "operator":"Exists"}]'
+    spec:
+      containers:
+      - name: autoscaler
+        image: gcr.io/google_containers/cluster-proportional-autoscaler-amd64:1.0.0
+        resources:
+            requests:
+                cpu: "20m"
+                memory: "10Mi"
+        command:
+          - /cluster-proportional-autoscaler
+          - --namespace=kube-system
+          - --configmap=kube-dns-autoscaler
+          - --mode=linear
+          # Should keep target in sync with cluster/addons/dns/skydns-rc.yaml.base
+          - --target=ReplicationController/kube-dns-v20
+          # When cluster is using large nodes(with more cores), "coresPerReplica" should dominate.
+          # If using small nodes, "nodesPerReplica" should dominate.
+          - --default-params={"linear":{"coresPerReplica":256,"nodesPerReplica":16,"min":1}}
+          - --logtostderr=true
+          - --v=2

cluster/addons/dns/skydns-rc.yaml.base

@@ -13,6 +13,8 @@
 # limitations under the License.
 
 # TODO - At some point, we need to rename all skydns-*.yaml.* files to kubedns-*.yaml.*
+# Should keep target in cluster/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml
+# in sync with this file.
 
 # __MACHINE_GENERATED_WARNING__
 

cluster/addons/dns/skydns-rc.yaml.in

@@ -13,6 +13,8 @@
 # limitations under the License.
 
 # TODO - At some point, we need to rename all skydns-*.yaml.* files to kubedns-*.yaml.*
+# Should keep target in cluster/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml
+# in sync with this file.
 
 # Warning: This is a file generated from the base underscore template file: skydns-rc.yaml.base
 

cluster/addons/dns/skydns-rc.yaml.sed

@@ -13,6 +13,8 @@
 # limitations under the License.
 
 # TODO - At some point, we need to rename all skydns-*.yaml.* files to kubedns-*.yaml.*
+# Should keep target in cluster/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml
+# in sync with this file.
 
 # Warning: This is a file generated from the base underscore template file: skydns-rc.yaml.base
 

cluster/aws/config-default.sh

@@ -122,6 +122,9 @@ DNS_SERVER_IP="${DNS_SERVER_IP:-10.0.0.10}"
 DNS_DOMAIN="cluster.local"
 DNS_REPLICAS=1
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false}"
+
 # Optional: Install Kubernetes UI
 ENABLE_CLUSTER_UI="${KUBE_ENABLE_CLUSTER_UI:-true}"
 

cluster/aws/config-test.sh

@@ -108,6 +108,9 @@ DNS_SERVER_IP="${DNS_SERVER_IP:-10.0.0.10}"
 DNS_DOMAIN="cluster.local"
 DNS_REPLICAS=1
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false}"
+
 # Optional: Install Kubernetes UI
 ENABLE_CLUSTER_UI="${KUBE_ENABLE_CLUSTER_UI:-true}"
 

cluster/common.sh

@@ -608,6 +608,7 @@ CLUSTER_REGISTRY_DISK_SIZE: $(yaml-quote ${CLUSTER_REGISTRY_DISK_SIZE:-})
 DNS_REPLICAS: $(yaml-quote ${DNS_REPLICAS:-})
 DNS_SERVER_IP: $(yaml-quote ${DNS_SERVER_IP:-})
 DNS_DOMAIN: $(yaml-quote ${DNS_DOMAIN:-})
+ENABLE_DNS_HORIZONTAL_AUTOSCALER: $(yaml-quote ${ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false})
 KUBELET_TOKEN: $(yaml-quote ${KUBELET_TOKEN:-})
 KUBE_PROXY_TOKEN: $(yaml-quote ${KUBE_PROXY_TOKEN:-})
 ADMISSION_CONTROL: $(yaml-quote ${ADMISSION_CONTROL:-})

cluster/gce/config-default.sh

@@ -115,6 +115,9 @@ DNS_SERVER_IP="${KUBE_DNS_SERVER_IP:-10.0.0.10}"
 DNS_DOMAIN="${KUBE_DNS_DOMAIN:-cluster.local}"
 DNS_REPLICAS=1
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-true}"
+
 # Optional: Install cluster docker registry.
 ENABLE_CLUSTER_REGISTRY="${KUBE_ENABLE_CLUSTER_REGISTRY:-false}"
 CLUSTER_REGISTRY_DISK="${CLUSTER_REGISTRY_PD:-${INSTANCE_PREFIX}-kube-system-kube-registry}"

cluster/gce/config-test.sh

@@ -142,6 +142,9 @@ DNS_SERVER_IP="10.0.0.10"
 DNS_DOMAIN="cluster.local"
 DNS_REPLICAS=1
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-true}"
+
 # Optional: Install cluster docker registry.
 ENABLE_CLUSTER_REGISTRY="${KUBE_ENABLE_CLUSTER_REGISTRY:-false}"
 CLUSTER_REGISTRY_DISK="${CLUSTER_REGISTRY_DISK:-${INSTANCE_PREFIX}-kube-system-kube-registry}"

cluster/gce/configure-vm.sh

@@ -442,6 +442,7 @@ enable_cluster_registry: '$(echo "$ENABLE_CLUSTER_REGISTRY" | sed -e "s/'/''/g")
 dns_replicas: '$(echo "$DNS_REPLICAS" | sed -e "s/'/''/g")'
 dns_server: '$(echo "$DNS_SERVER_IP" | sed -e "s/'/''/g")'
 dns_domain: '$(echo "$DNS_DOMAIN" | sed -e "s/'/''/g")'
+enable_dns_horizontal_autoscaler: '$(echo "$ENABLE_DNS_HORIZONTAL_AUTOSCALER" | sed -e "s/'/''/g")'
 admission_control: '$(echo "$ADMISSION_CONTROL" | sed -e "s/'/''/g")'
 network_provider: '$(echo "$NETWORK_PROVIDER" | sed -e "s/'/''/g")'
 prepull_e2e_images: '$(echo "$PREPULL_E2E_IMAGES" | sed -e "s/'/''/g")'

cluster/gce/coreos/configure-node.sh

@@ -135,6 +135,9 @@ function configure-master-addons() {
 
   if [[ "${ENABLE_CLUSTER_DNS}" == "true" ]]; then
     evaluate-manifests-dir ${MANIFESTS_DIR}/addons/dns ${addon_dir}/dns
+    if [[ "${ENABLE_DNS_HORIZONTAL_AUTOSCALER}" == "true" ]]; then
+      evaluate-manifests-dir ${MANIFESTS_DIR}/addons/dns-horizontal-autoscaler ${addon_dir}/dns-horizontal-autoscaler
+    fi
   fi
 
   if [[ "${ENABLE_CLUSTER_UI}" == "true" ]]; then

cluster/gce/gci/configure-helper.sh

@@ -1030,6 +1030,10 @@ function start-kube-addons {
     sed -i -e "s@{{ *pillar\['dns_domain'\] *}}@${DNS_DOMAIN}@g" "${dns_rc_file}"
     sed -i -e "s@{{ *pillar\['dns_server'\] *}}@${DNS_SERVER_IP}@g" "${dns_svc_file}"
 
+    if [[ "${ENABLE_DNS_HORIZONTAL_AUTOSCALER:-}" == "true" ]]; then
+      setup-addon-manifests "addons" "dns-horizontal-autoscaler"
+    fi
+
     if [[ "${FEDERATION:-}" == "true" ]]; then
       local federations_domain_map="${FEDERATIONS_DOMAIN_MAP:-}"
       if [[ -z "${federations_domain_map}" && -n "${FEDERATION_NAME:-}" && -n "${DNS_ZONE_NAME:-}" ]]; then

cluster/gce/trusty/configure-helper.sh

@@ -879,6 +879,10 @@ start_kube_addons() {
     sed -i -e "s@{{ *pillar\['dns_domain'\] *}}@${DNS_DOMAIN}@g" "${dns_rc_file}"
     sed -i -e "s@{{ *pillar\['dns_server'\] *}}@${DNS_SERVER_IP}@g" "${dns_svc_file}"
 
+    if [[ "${ENABLE_DNS_HORIZONTAL_AUTOSCALER:-}" == "true" ]]; then
+      setup_addon_manifests "addons" "dns-horizontal-autoscaler"
+    fi
+
     if [[ "${FEDERATION:-}" == "true" ]]; then
       FEDERATIONS_DOMAIN_MAP="${FEDERATIONS_DOMAIN_MAP:-}"
       if [[ -z "${FEDERATIONS_DOMAIN_MAP}" && -n "${FEDERATION_NAME:-}" && -n "${DNS_ZONE_NAME:-}" ]]; then

cluster/gke/config-default.sh

@@ -41,4 +41,7 @@ ENABLE_L7_LOADBALANCING="${KUBE_ENABLE_L7_LOADBALANCING:-glbc}"
 #   standalone     - Heapster only. Metrics available via Heapster REST API.
 ENABLE_CLUSTER_MONITORING="${KUBE_ENABLE_CLUSTER_MONITORING:-standalone}"
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false}"
+
 KUBE_DELETE_NETWORK=${KUBE_DELETE_NETWORK:-false}

cluster/libvirt-coreos/config-default.sh

@@ -59,6 +59,9 @@ DNS_SERVER_IP="${SERVICE_CLUSTER_IP_RANGE%.*}.254"
 DNS_DOMAIN="cluster.local"
 DNS_REPLICAS=1
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false}"
+
 #Generate dns files
 sed -f "${KUBE_ROOT}/cluster/addons/dns/transforms2sed.sed" < "${KUBE_ROOT}/cluster/addons/dns/skydns-rc.yaml.base" | sed -f "${KUBE_ROOT}/cluster/libvirt-coreos/forShellEval.sed"  > "${KUBE_ROOT}/cluster/libvirt-coreos/skydns-rc.yaml"
 sed -f "${KUBE_ROOT}/cluster/addons/dns/transforms2sed.sed" < "${KUBE_ROOT}/cluster/addons/dns/skydns-svc.yaml.base" | sed -f "${KUBE_ROOT}/cluster/libvirt-coreos/forShellEval.sed"  > "${KUBE_ROOT}/cluster/libvirt-coreos/skydns-svc.yaml"

cluster/mesos/docker/config-default.sh

@@ -34,6 +34,9 @@ DNS_SERVER_IP="10.10.10.10"
 DNS_DOMAIN="cluster.local"
 DNS_REPLICAS=1
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false}"
+
 # Optional: Deploy cluster web interface.
 ENABLE_CLUSTER_UI=true
 

cluster/openstack-heat/kubernetes-heat/fragments/configure-salt.yaml

@@ -51,6 +51,7 @@ write_files:
       dns_replicas: "1"
       dns_server: 10.246.0.10
       dns_domain: cluster.local
+      enable_dns_horizontal_autoscaler: "false"
       federations_domain_map: ''
       instance_prefix: kubernetes
       admission_control: NamespaceLifecycle,LimitRanger,SecurityContextDeny,ServiceAccount,DefaultStorageClass,ResourceQuota

cluster/photon-controller/config-default.sh

@@ -79,6 +79,9 @@ DNS_SERVER_IP="10.244.240.240"
 DNS_DOMAIN="cluster.local"
 DNS_REPLICAS=1
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false}"
+
 # Optional: Install Kubernetes UI
 ENABLE_CLUSTER_UI=true
 

cluster/rackspace/config-default.sh

@@ -58,5 +58,8 @@ DNS_SERVER_IP="10.0.0.10"
 DNS_DOMAIN="cluster.local"
 DNS_REPLICAS=1
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false}"
+
 # Optional: Install Kubernetes UI
 ENABLE_CLUSTER_UI="${KUBE_ENABLE_CLUSTER_UI:-true}"

cluster/saltbase/salt/kube-addons/init.sls

@@ -90,6 +90,17 @@ addon-dir-create:
     - makedirs: True
 {% endif %}
 
+{% if pillar.get('enable_dns_horizontal_autoscaler', '').lower() == 'true'
+   and pillar.get('enable_cluster_dns', '').lower() == 'true' %}
+/etc/kubernetes/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml:
+  file.managed:
+    - source: salt://kube-addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml
+    - user: root
+    - group: root
+    - file_mode: 644
+    - makedirs: True
+{% endif %}
+
 {% if pillar.get('enable_cluster_registry', '').lower() == 'true' %}
 /etc/kubernetes/addons/registry/registry-svc.yaml:
   file.managed:

cluster/ubuntu/config-default.sh

@@ -118,6 +118,9 @@ DNS_SERVER_IP=${DNS_SERVER_IP:-"192.168.3.10"}
 DNS_DOMAIN=${DNS_DOMAIN:-"cluster.local"}
 DNS_REPLICAS=${DNS_REPLICAS:-1}
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false}"
+
 # Optional: Install Kubernetes UI
 ENABLE_CLUSTER_UI="${KUBE_ENABLE_CLUSTER_UI:-true}"
 

cluster/vagrant/config-default.sh

@@ -88,6 +88,9 @@ DNS_SERVER_IP="10.247.0.10"
 DNS_DOMAIN="cluster.local"
 DNS_REPLICAS=1
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false}"
+
 # Optional: Install Kubernetes UI
 ENABLE_CLUSTER_UI="${KUBE_ENABLE_CLUSTER_UI:-true}"
 

cluster/vsphere/config-default.sh

@@ -55,6 +55,9 @@ DNS_SERVER_IP="10.244.240.240"
 DNS_DOMAIN="cluster.local"
 DNS_REPLICAS=1
 
+# Optional: Enable DNS horizontal autoscaler
+ENABLE_DNS_HORIZONTAL_AUTOSCALER="${KUBE_ENABLE_DNS_HORIZONTAL_AUTOSCALER:-false}"
+
 # Optional: Install Kubernetes UI
 ENABLE_CLUSTER_UI="${KUBE_ENABLE_CLUSTER_UI:-true}"
 

test/e2e/BUILD

@@ -29,6 +29,7 @@ go_library(
         "density.go",
         "deployment.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