Add phase command for dynamic kubelet configuration in kubeadm.

cmd/kubeadm/app/cmd/phases/kubelet.go

@@ -0,0 +1,200 @@
+/*
+Copyright 2018 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 phases
+
+import (
+	"fmt"
+	"io/ioutil"
+
+	"github.com/spf13/cobra"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	kubeadmapiext "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha1"
+	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
+	"k8s.io/kubernetes/cmd/kubeadm/app/features"
+	kubeletphase "k8s.io/kubernetes/cmd/kubeadm/app/phases/kubelet"
+	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
+	configutil "k8s.io/kubernetes/cmd/kubeadm/app/util/config"
+	kubeconfigutil "k8s.io/kubernetes/cmd/kubeadm/app/util/kubeconfig"
+	"k8s.io/kubernetes/pkg/api/legacyscheme"
+	nodeutil "k8s.io/kubernetes/pkg/util/node"
+	"k8s.io/kubernetes/pkg/util/normalizer"
+)
+
+var (
+	kubeletWriteInitConfigLongDesc = normalizer.LongDesc(`
+		Writes init kubelet configuration to disk for dynamic kubelet configuration feature.
+		Please note that the kubelet configuration can be passed to kubeadm as a value into the master configuration file.
+		` + cmdutil.AlphaDisclaimer)
+
+	kubeletWriteInitConfigExample = normalizer.Examples(`
+		# Writes init kubelet configuration to disk.
+		kubeadm alpha phase kubelet init
+		`)
+
+	kubeletUploadDynamicConfigLongDesc = normalizer.LongDesc(`
+		Uploads dynamic kubelet configuration as ConfigMap and links it to the current node as ConfigMapRef.
+		Please note that the kubelet configuration can be passed to kubeadm as a value into the master configuration file.
+		` + cmdutil.AlphaDisclaimer)
+
+	kubeletUploadDynamicConfigExample = normalizer.Examples(`
+		# Uploads dynamic kubelet configuration as ConfigMap.
+		kubeadm alpha phase kubelet upload
+		`)
+
+	kubeletEnableDynamicConfigLongDesc = normalizer.LongDesc(`
+		Enables dynamic kubelet configuration on node. This should be run on nodes.
+		Please note that the kubelet configuration can be passed to kubeadm as a value into the master configuration file.
+		` + cmdutil.AlphaDisclaimer)
+
+	kubeletEnableDynamicConfigExample = normalizer.Examples(`
+		# Enables dynamic kubelet configuration on node.
+		kubeadm alpha phase kubelet enable
+		`)
+)
+
+// NewCmdKubelet returns main command for Kubelet phase
+func NewCmdKubelet() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "kubelet",
+		Short: "Adopts dynamic kubelet configuration.",
+		Long:  cmdutil.MacroCommandLongDescription,
+	}
+
+	cmd.AddCommand(NewCmdKubeletWriteInitConfig())
+	cmd.AddCommand(NewCmdKubeletUploadDynamicConfig())
+	cmd.AddCommand(NewCmdKubeletEnableDynamicConfig())
+
+	return cmd
+}
+
+// NewCmdKubeletWriteInitConfig calls cobra.Command for writing init kubelet configuration
+func NewCmdKubeletWriteInitConfig() *cobra.Command {
+	var cfgPath string
+	cmd := &cobra.Command{
+		Use:     "init",
+		Short:   "Writes init kubelet configuration to disk",
+		Long:    kubeletWriteInitConfigLongDesc,
+		Example: kubeletWriteInitConfigExample,
+		Run: func(cmd *cobra.Command, args []string) {
+			cfg := &kubeadmapiext.MasterConfiguration{
+				// KubernetesVersion is not used by kubelet init, but we set this explicitly to avoid
+				// the lookup of the version from the internet when executing ConfigFileAndDefaultsToInternalConfig
+				KubernetesVersion: "v1.9.0",
+			}
+			legacyscheme.Scheme.Default(cfg)
+
+			// This call returns the ready-to-use configuration based on the configuration file that might or might not exist and the default cfg populated by flags
+			internalcfg, err := configutil.ConfigFileAndDefaultsToInternalConfig(cfgPath, cfg)
+			kubeadmutil.CheckErr(err)
+			if features.Enabled(internalcfg.FeatureGates, features.DynamicKubeletConfig) {
+				err = kubeletphase.WriteInitKubeletConfigToDiskOnMaster(internalcfg)
+				kubeadmutil.CheckErr(err)
+			} else {
+				fmt.Println("[kubelet] feature gate DynamicKubeletConfig is not enabled, do nothing.")
+			}
+		},
+	}
+
+	cmd.Flags().StringVar(&cfgPath, "config", cfgPath, "Path to kubeadm config file (WARNING: Usage of a configuration file is experimental)")
+
+	return cmd
+}
+
+// NewCmdKubeletUploadDynamicConfig calls cobra.Command for uploading dynamic kubelet configuration
+func NewCmdKubeletUploadDynamicConfig() *cobra.Command {
+	var cfgPath, kubeConfigFile string
+
+	cmd := &cobra.Command{
+		Use:     "upload",
+		Short:   "Uploads dynamic kubelet configuration as ConfigMap",
+		Long:    kubeletUploadDynamicConfigLongDesc,
+		Example: kubeletUploadDynamicConfigExample,
+		Run: func(cmd *cobra.Command, args []string) {
+			cfg := &kubeadmapiext.MasterConfiguration{
+				// KubernetesVersion is not used by kubelet upload, but we set this explicitly to avoid
+				// the lookup of the version from the internet when executing ConfigFileAndDefaultsToInternalConfig
+				KubernetesVersion: "v1.9.0",
+			}
+			legacyscheme.Scheme.Default(cfg)
+
+			// This call returns the ready-to-use configuration based on the configuration file that might or might not exist and the default cfg populated by flags
+			internalcfg, err := configutil.ConfigFileAndDefaultsToInternalConfig(cfgPath, cfg)
+			kubeadmutil.CheckErr(err)
+			if features.Enabled(internalcfg.FeatureGates, features.DynamicKubeletConfig) {
+				client, err := kubeconfigutil.ClientSetFromFile(kubeConfigFile)
+				kubeadmutil.CheckErr(err)
+				err = kubeletphase.CreateBaseKubeletConfiguration(internalcfg, client)
+				kubeadmutil.CheckErr(err)
+			} else {
+				fmt.Println("[kubelet] feature gate DynamicKubeletConfig is not enabled, do nothing.")
+			}
+		},
+	}
+
+	cmd.Flags().StringVar(&cfgPath, "config", cfgPath, "Path to kubeadm config file (WARNING: Usage of a configuration file is experimental)")
+	cmd.Flags().StringVar(&kubeConfigFile, "kubeconfig", "/etc/kubernetes/admin.conf", "The KubeConfig file to use when talking to the cluster")
+
+	return cmd
+}
+
+// NewCmdKubeletEnableDynamicConfig calls cobra.Command for enabling dynamic kubelet configuration on node
+func NewCmdKubeletEnableDynamicConfig() *cobra.Command {
+	cfg := &kubeadmapiext.NodeConfiguration{}
+	legacyscheme.Scheme.Default(cfg)
+
+	var cfgPath string
+	cmd := &cobra.Command{
+		Use:     "enable",
+		Short:   "Enables dynamic kubelet configuration on node",
+		Long:    kubeletEnableDynamicConfigLongDesc,
+		Example: kubeletEnableDynamicConfigExample,
+		Run: func(cmd *cobra.Command, args []string) {
+			nodeName, err := getNodeName(cfgPath, cfg)
+			kubeadmutil.CheckErr(err)
+			if features.Enabled(cfg.FeatureGates, features.DynamicKubeletConfig) {
+				err = kubeletphase.ConsumeBaseKubeletConfiguration(nodeName)
+				kubeadmutil.CheckErr(err)
+			} else {
+				fmt.Println("[kubelet] feature gate DynamicKubeletConfig is not enabled, do nothing.")
+			}
+		},
+	}
+
+	cmd.Flags().StringVar(&cfgPath, "config", cfgPath, "Path to kubeadm config file (WARNING: Usage of a configuration file is experimental)")
+	cmd.Flags().StringVar(&cfg.NodeName, "node-name", cfg.NodeName, "Name of the node that should enable the dynamic kubelet configuration")
+
+	return cmd
+}
+
+func getNodeName(cfgPath string, cfg *kubeadmapiext.NodeConfiguration) (string, error) {
+	if cfgPath != "" {
+		b, err := ioutil.ReadFile(cfgPath)
+		if err != nil {
+			return "", fmt.Errorf("unable to read config from %q [%v]", cfgPath, err)
+		}
+		if err := runtime.DecodeInto(legacyscheme.Codecs.UniversalDecoder(), b, cfg); err != nil {
+			return "", fmt.Errorf("unable to decode config from %q [%v]", cfgPath, err)
+		}
+	}
+
+	if cfg.NodeName == "" {
+		cfg.NodeName = nodeutil.GetHostname("")
+	}
+
+	return cfg.NodeName, nil
+}

cmd/kubeadm/app/cmd/phases/phase.go

@@ -36,6 +36,7 @@ func NewCmdPhase(out io.Writer) *cobra.Command {
 	cmd.AddCommand(NewCmdCerts())
 	cmd.AddCommand(NewCmdControlplane())
 	cmd.AddCommand(NewCmdEtcd())
+	cmd.AddCommand(NewCmdKubelet())
 	cmd.AddCommand(NewCmdKubeConfig(out))
 	cmd.AddCommand(NewCmdMarkMaster())
 	cmd.AddCommand(NewCmdPreFlight())