8ec1958667
This explicitly registers Kubelet flags from libraries that were registering flags globally, and stops parsing the global flag set. In general, we should always be explicit about flags we register and parse, so that we maintain control over our command-line API.
129 lines
4.0 KiB
Go
129 lines
4.0 KiB
Go
/*
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Copyright 2014 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// The kubelet binary is responsible for maintaining a set of containers on a particular host VM.
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// It syncs data from both configuration file(s) as well as from a quorum of etcd servers.
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// It then queries Docker to see what is currently running. It synchronizes the configuration data,
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// with the running set of containers by starting or stopping Docker containers.
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package main
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import (
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"fmt"
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"os"
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"github.com/golang/glog"
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"github.com/spf13/pflag"
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utilfeature "k8s.io/apiserver/pkg/util/feature"
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"k8s.io/apiserver/pkg/util/flag"
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"k8s.io/apiserver/pkg/util/logs"
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"k8s.io/kubernetes/cmd/kubelet/app"
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"k8s.io/kubernetes/cmd/kubelet/app/options"
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_ "k8s.io/kubernetes/pkg/client/metrics/prometheus" // for client metric registration
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_ "k8s.io/kubernetes/pkg/version/prometheus" // for version metric registration
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"k8s.io/kubernetes/pkg/version/verflag"
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)
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func parseFlagSet(fs *pflag.FlagSet, args []string) error {
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if err := fs.Parse(args); err != nil {
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return err
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}
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fs.VisitAll(func(flag *pflag.Flag) {
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glog.V(2).Infof("FLAG: --%s=%q", flag.Name, flag.Value)
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})
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return nil
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}
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func die(err error) {
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fmt.Fprintf(os.Stderr, "error: %v\n", err)
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os.Exit(1)
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}
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func main() {
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fs := pflag.NewFlagSet(os.Args[0], pflag.ExitOnError)
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// set the normalize func, similar to k8s.io/apiserver/pkg/util/flag/flags.go:InitFlags
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fs.SetNormalizeFunc(flag.WordSepNormalizeFunc)
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// explicitly add flags from libs that register global flags
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options.AddGlobalFlags(fs)
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// register kubelet flags
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kubeletFlags := options.NewKubeletFlags()
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kubeletFlags.AddFlags(fs)
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// register kubelet config flags
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defaultConfig, err := options.NewKubeletConfiguration()
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if err != nil {
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die(err)
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}
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options.AddKubeletConfigFlags(fs, defaultConfig)
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// parse flags
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if err := parseFlagSet(fs, os.Args[1:]); err != nil {
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die(err)
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}
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// initialize logging and defer flush
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logs.InitLogs()
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defer logs.FlushLogs()
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// short-circuit on verflag
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verflag.PrintAndExitIfRequested()
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// TODO(mtaufen): won't need this this once dynamic config is GA
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// set feature gates so we can check if dynamic config is enabled
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if err := utilfeature.DefaultFeatureGate.SetFromMap(defaultConfig.FeatureGates); err != nil {
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die(err)
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}
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// validate the initial KubeletFlags, to make sure the dynamic-config-related flags aren't used unless the feature gate is on
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if err := options.ValidateKubeletFlags(kubeletFlags); err != nil {
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die(err)
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}
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// bootstrap the kubelet config controller, app.BootstrapKubeletConfigController will check
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// feature gates and only turn on relevant parts of the controller
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kubeletConfig, kubeletConfigController, err := app.BootstrapKubeletConfigController(
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defaultConfig, kubeletFlags.KubeletConfigFile, kubeletFlags.DynamicConfigDir)
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if err != nil {
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die(err)
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}
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// construct a KubeletServer from kubeletFlags and kubeletConfig
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kubeletServer := &options.KubeletServer{
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KubeletFlags: *kubeletFlags,
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KubeletConfiguration: *kubeletConfig,
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}
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// use kubeletServer to construct the default KubeletDeps
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kubeletDeps, err := app.UnsecuredDependencies(kubeletServer)
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if err != nil {
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die(err)
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}
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// add the kubelet config controller to kubeletDeps
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kubeletDeps.KubeletConfigController = kubeletConfigController
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// start the experimental docker shim, if enabled
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if kubeletFlags.ExperimentalDockershim {
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if err := app.RunDockershim(kubeletFlags, kubeletConfig); err != nil {
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die(err)
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}
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}
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// run the kubelet
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if err := app.Run(kubeletServer, kubeletDeps); err != nil {
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die(err)
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}
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}
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