Node e2e test for Dynamic Kubelet Configuration

test/e2e_node/dynamic_kubelet_configuration_test.go

@@ -0,0 +1,195 @@
+/*
+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_node
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"time"
+
+	"github.com/golang/glog"
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/apis/componentconfig"
+	"k8s.io/kubernetes/pkg/apis/componentconfig/v1alpha1"
+	"k8s.io/kubernetes/test/e2e/framework"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+// This test is marked [Disruptive] because the Kubelet temporarily goes down as part of of this test.
+var _ = framework.KubeDescribe("DynamicKubeletConfiguration [Feature:dynamicKubeletConfig] [Disruptive]", func() {
+	f := framework.NewDefaultFramework("dynamic-kubelet-configuration-test")
+
+	Context("When a configmap called `kubelet-<node-name>` is added to the `kube-system` namespace", func() {
+		It("The Kubelet on that node should restart to take up the new config", func() {
+			const (
+				restartGap = 40 * time.Second
+			)
+
+			// Get the current KubeletConfiguration (known to be valid) by
+			// querying the configz endpoint for the current node.
+			resp := pollConfigz(2*time.Minute, 5*time.Second)
+			kubeCfg, err := decodeConfigz(resp)
+			framework.ExpectNoError(err)
+			glog.Infof("KubeletConfiguration - Initial values: %+v", *kubeCfg)
+
+			// Change a safe value e.g. file check frequency.
+			// Make sure we're providing a value distinct from the current one.
+			oldFileCheckFrequency := kubeCfg.FileCheckFrequency.Duration
+			newFileCheckFrequency := 11 * time.Second
+			if kubeCfg.FileCheckFrequency.Duration == newFileCheckFrequency {
+				newFileCheckFrequency = 10 * time.Second
+			}
+			kubeCfg.FileCheckFrequency.Duration = newFileCheckFrequency
+
+			// Use the new config to create a new kube-<node-name> configmap in `kube-system` namespace.
+			_, err = createConfigMap(f, kubeCfg)
+			framework.ExpectNoError(err)
+
+			// Give the Kubelet time to see that there is new config and restart. If we don't do this,
+			// the Kubelet will still have the old config when we poll, and the test will fail.
+			time.Sleep(restartGap)
+
+			// Use configz to get the new config.
+			resp = pollConfigz(2*time.Minute, 5*time.Second)
+			kubeCfg, err = decodeConfigz(resp)
+			framework.ExpectNoError(err)
+			glog.Infof("KubeletConfiguration - After modification of FileCheckFrequency: %+v", *kubeCfg)
+
+			// We expect to see the new value in the new config.
+			Expect(kubeCfg.FileCheckFrequency.Duration).To(Equal(newFileCheckFrequency))
+
+			// Change the config back to what it originally was.
+			kubeCfg.FileCheckFrequency.Duration = oldFileCheckFrequency
+			_, err = updateConfigMap(f, kubeCfg)
+			framework.ExpectNoError(err)
+
+			// Give the Kubelet time to see that there is new config and restart. If we don't do this,
+			// the Kubelet will still have the old config when we poll, and the test will fail.
+			time.Sleep(restartGap)
+
+			// User configz to get the new config.
+			resp = pollConfigz(2*time.Minute, 5*time.Second)
+			kubeCfg, err = decodeConfigz(resp)
+			framework.ExpectNoError(err)
+			glog.Infof("KubeletConfiguration - After restoration of FileCheckFrequency: %+v", *kubeCfg)
+
+			// We expect to see the original value restored in the new config.
+			Expect(kubeCfg.FileCheckFrequency.Duration).To(Equal(oldFileCheckFrequency))
+		})
+	})
+})
+
+// This function either causes the test to fail, or it returns a status 200 response.
+func pollConfigz(timeout time.Duration, pollInterval time.Duration) *http.Response {
+	endpoint := fmt.Sprintf("http://127.0.0.1:8080/api/v1/proxy/nodes/%s/configz", framework.TestContext.NodeName)
+	client := &http.Client{}
+	req, err := http.NewRequest("GET", endpoint, nil)
+	framework.ExpectNoError(err)
+	req.Header.Add("Accept", "application/json")
+
+	var resp *http.Response
+	Eventually(func() bool {
+		resp, err = client.Do(req)
+		if err != nil {
+			glog.Errorf("Failed to get /configz, retrying. Error: %v", err)
+			return false
+		}
+		if resp.StatusCode != 200 {
+			glog.Errorf("/configz response status not 200, retrying. Response was: %+v", resp)
+			return false
+		}
+		return true
+	}, timeout, pollInterval).Should(Equal(true))
+	return resp
+}
+
+// Decodes the http response  from /configz and returns a componentconfig.KubeletConfiguration (internal type).
+func decodeConfigz(resp *http.Response) (*componentconfig.KubeletConfiguration, error) {
+	// This hack because /configz reports the following structure:
+	// {"componentconfig": {the JSON representation of v1alpha1.KubeletConfiguration}}
+	type configzWrapper struct {
+		ComponentConfig v1alpha1.KubeletConfiguration `json:"componentconfig"`
+	}
+
+	configz := configzWrapper{}
+	kubeCfg := componentconfig.KubeletConfiguration{}
+
+	contentsBytes, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	err = json.Unmarshal(contentsBytes, &configz)
+	if err != nil {
+		return nil, err
+	}
+
+	err = api.Scheme.Convert(&configz.ComponentConfig, &kubeCfg, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return &kubeCfg, nil
+}
+
+// Uses KubeletConfiguration to create a `kubelet-<node-name>` ConfigMap in the "kube-system" namespace.
+func createConfigMap(f *framework.Framework, kubeCfg *componentconfig.KubeletConfiguration) (*api.ConfigMap, error) {
+	kubeCfgExt := v1alpha1.KubeletConfiguration{}
+	api.Scheme.Convert(kubeCfg, &kubeCfgExt, nil)
+
+	bytes, err := json.Marshal(kubeCfgExt)
+	framework.ExpectNoError(err)
+
+	cmap, err := f.Client.ConfigMaps("kube-system").Create(&api.ConfigMap{
+		ObjectMeta: api.ObjectMeta{
+			Name: fmt.Sprintf("kubelet-%s", framework.TestContext.NodeName),
+		},
+		Data: map[string]string{
+			"kubelet.config": string(bytes),
+		},
+	})
+	if err != nil {
+		return nil, err
+	}
+	return cmap, nil
+}
+
+// Similar to createConfigMap, except this updates an existing ConfigMap.
+func updateConfigMap(f *framework.Framework, kubeCfg *componentconfig.KubeletConfiguration) (*api.ConfigMap, error) {
+	kubeCfgExt := v1alpha1.KubeletConfiguration{}
+	api.Scheme.Convert(kubeCfg, &kubeCfgExt, nil)
+
+	bytes, err := json.Marshal(kubeCfgExt)
+	framework.ExpectNoError(err)
+
+	cmap, err := f.Client.ConfigMaps("kube-system").Update(&api.ConfigMap{
+		ObjectMeta: api.ObjectMeta{
+			Name: fmt.Sprintf("kubelet-%s", framework.TestContext.NodeName),
+		},
+		Data: map[string]string{
+			"kubelet.config": string(bytes),
+		},
+	})
+	if err != nil {
+		return nil, err
+	}
+	return cmap, nil
+}