ceph-csi/vendor/k8s.io/kubernetes/cmd/kubelet/kubelet.go
Serguei Bezverkhi 7b24313bd6 vendor files
2018-01-10 13:42:26 -05:00

110 lines
3.6 KiB
Go

/*
Copyright 2014 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.
*/
// The kubelet binary is responsible for maintaining a set of containers on a particular host VM.
// It syncs data from both configuration file(s) as well as from a quorum of etcd servers.
// It then queries Docker to see what is currently running. It synchronizes the configuration data,
// with the running set of containers by starting or stopping Docker containers.
package main
import (
"fmt"
"os"
"github.com/spf13/pflag"
utilfeature "k8s.io/apiserver/pkg/util/feature"
"k8s.io/apiserver/pkg/util/flag"
"k8s.io/apiserver/pkg/util/logs"
"k8s.io/kubernetes/cmd/kubelet/app"
"k8s.io/kubernetes/cmd/kubelet/app/options"
_ "k8s.io/kubernetes/pkg/client/metrics/prometheus" // for client metric registration
_ "k8s.io/kubernetes/pkg/version/prometheus" // for version metric registration
"k8s.io/kubernetes/pkg/version/verflag"
)
func die(err error) {
fmt.Fprintf(os.Stderr, "error: %v\n", err)
os.Exit(1)
}
func main() {
// construct KubeletFlags object and register command line flags mapping
kubeletFlags := options.NewKubeletFlags()
kubeletFlags.AddFlags(pflag.CommandLine)
// construct KubeletConfiguration object and register command line flags mapping
defaultConfig, err := options.NewKubeletConfiguration()
if err != nil {
die(err)
}
options.AddKubeletConfigFlags(pflag.CommandLine, defaultConfig)
// parse the command line flags into the respective objects
flag.InitFlags()
// initialize logging and defer flush
logs.InitLogs()
defer logs.FlushLogs()
// short-circuit on verflag
verflag.PrintAndExitIfRequested()
// TODO(mtaufen): won't need this this once dynamic config is GA
// set feature gates so we can check if dynamic config is enabled
if err := utilfeature.DefaultFeatureGate.SetFromMap(defaultConfig.FeatureGates); err != nil {
die(err)
}
// validate the initial KubeletFlags, to make sure the dynamic-config-related flags aren't used unless the feature gate is on
if err := options.ValidateKubeletFlags(kubeletFlags); err != nil {
die(err)
}
// bootstrap the kubelet config controller, app.BootstrapKubeletConfigController will check
// feature gates and only turn on relevant parts of the controller
kubeletConfig, kubeletConfigController, err := app.BootstrapKubeletConfigController(
defaultConfig, kubeletFlags.InitConfigDir, kubeletFlags.DynamicConfigDir)
if err != nil {
die(err)
}
// construct a KubeletServer from kubeletFlags and kubeletConfig
kubeletServer := &options.KubeletServer{
KubeletFlags: *kubeletFlags,
KubeletConfiguration: *kubeletConfig,
}
// use kubeletServer to construct the default KubeletDeps
kubeletDeps, err := app.UnsecuredDependencies(kubeletServer)
if err != nil {
die(err)
}
// add the kubelet config controller to kubeletDeps
kubeletDeps.KubeletConfigController = kubeletConfigController
// start the experimental docker shim, if enabled
if kubeletFlags.ExperimentalDockershim {
if err := app.RunDockershim(kubeletFlags, kubeletConfig); err != nil {
die(err)
}
}
// run the kubelet
if err := app.Run(kubeletServer, kubeletDeps); err != nil {
die(err)
}
}