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controllermanager.go
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controllermanager.go
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/*
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.
*/
// Package app implements a server that runs a set of active
// components. This includes replication controllers, service endpoints and
// nodes.
//
package app
import (
"fmt"
"io/ioutil"
"math/rand"
"net"
"net/http"
"net/http/pprof"
"os"
goruntime "runtime"
"strconv"
"time"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apimachinery/pkg/util/sets"
"k8s.io/apimachinery/pkg/util/wait"
"k8s.io/apiserver/pkg/server/healthz"
"k8s.io/client-go/discovery"
v1core "k8s.io/client-go/kubernetes/typed/core/v1"
clientv1 "k8s.io/client-go/pkg/api/v1"
restclient "k8s.io/client-go/rest"
"k8s.io/client-go/tools/clientcmd"
"k8s.io/client-go/tools/record"
certutil "k8s.io/client-go/util/cert"
"k8s.io/kubernetes/cmd/kube-controller-manager/app/options"
"k8s.io/kubernetes/pkg/api"
"k8s.io/kubernetes/pkg/client/clientset_generated/clientset"
informers "k8s.io/kubernetes/pkg/client/informers/informers_generated/externalversions"
"k8s.io/kubernetes/pkg/client/leaderelection"
"k8s.io/kubernetes/pkg/client/leaderelection/resourcelock"
"k8s.io/kubernetes/pkg/cloudprovider"
"k8s.io/kubernetes/pkg/controller"
serviceaccountcontroller "k8s.io/kubernetes/pkg/controller/serviceaccount"
"k8s.io/kubernetes/pkg/serviceaccount"
"k8s.io/kubernetes/pkg/util/configz"
"k8s.io/kubernetes/pkg/version"
"github.com/golang/glog"
"github.com/prometheus/client_golang/prometheus"
"github.com/spf13/cobra"
"github.com/spf13/pflag"
)
const (
// Jitter used when starting controller managers
ControllerStartJitter = 1.0
)
// NewControllerManagerCommand creates a *cobra.Command object with default parameters
func NewControllerManagerCommand() *cobra.Command {
s := options.NewCMServer()
s.AddFlags(pflag.CommandLine, KnownControllers(), ControllersDisabledByDefault.List())
cmd := &cobra.Command{
Use: "kube-controller-manager",
Long: `The Kubernetes controller manager is a daemon that embeds
the core control loops shipped with Kubernetes. In applications of robotics and
automation, a control loop is a non-terminating loop that regulates the state of
the system. In Kubernetes, a controller is a control loop that watches the shared
state of the cluster through the apiserver and makes changes attempting to move the
current state towards the desired state. Examples of controllers that ship with
Kubernetes today are the replication controller, endpoints controller, namespace
controller, and serviceaccounts controller.`,
Run: func(cmd *cobra.Command, args []string) {
},
}
return cmd
}
// ResyncPeriod returns a function which generates a duration each time it is
// invoked; this is so that multiple controllers don't get into lock-step and all
// hammer the apiserver with list requests simultaneously.
func ResyncPeriod(s *options.CMServer) func() time.Duration {
return func() time.Duration {
factor := rand.Float64() + 1
return time.Duration(float64(s.MinResyncPeriod.Nanoseconds()) * factor)
}
}
// Run runs the CMServer. This should never exit.
func Run(s *options.CMServer) error {
// To help debugging, immediately log version
glog.Infof("Version: %+v", version.Get())
if err := s.Validate(KnownControllers(), ControllersDisabledByDefault.List()); err != nil {
return err
}
if c, err := configz.New("componentconfig"); err == nil {
c.Set(s.KubeControllerManagerConfiguration)
} else {
glog.Errorf("unable to register configz: %s", err)
}
kubeconfig, err := clientcmd.BuildConfigFromFlags(s.Master, s.Kubeconfig)
if err != nil {
return err
}
kubeconfig.ContentConfig.ContentType = s.ContentType
// Override kubeconfig qps/burst settings from flags
kubeconfig.QPS = s.KubeAPIQPS
kubeconfig.Burst = int(s.KubeAPIBurst)
kubeClient, err := clientset.NewForConfig(restclient.AddUserAgent(kubeconfig, "controller-manager"))
if err != nil {
glog.Fatalf("Invalid API configuration: %v", err)
}
leaderElectionClient := clientset.NewForConfigOrDie(restclient.AddUserAgent(kubeconfig, "leader-election"))
go func() {
mux := http.NewServeMux()
healthz.InstallHandler(mux)
if s.EnableProfiling {
mux.HandleFunc("/debug/pprof/", pprof.Index)
mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
if s.EnableContentionProfiling {
goruntime.SetBlockProfileRate(1)
}
}
configz.InstallHandler(mux)
mux.Handle("/metrics", prometheus.Handler())
server := &http.Server{
Addr: net.JoinHostPort(s.Address, strconv.Itoa(int(s.Port))),
Handler: mux,
}
glog.Fatal(server.ListenAndServe())
}()
eventBroadcaster := record.NewBroadcaster()
eventBroadcaster.StartLogging(glog.Infof)
eventBroadcaster.StartRecordingToSink(&v1core.EventSinkImpl{Interface: v1core.New(kubeClient.Core().RESTClient()).Events("")})
recorder := eventBroadcaster.NewRecorder(api.Scheme, clientv1.EventSource{Component: "controller-manager"})
run := func(stop <-chan struct{}) {
rootClientBuilder := controller.SimpleControllerClientBuilder{
ClientConfig: kubeconfig,
}
var clientBuilder controller.ControllerClientBuilder
if len(s.ServiceAccountKeyFile) > 0 && s.UseServiceAccountCredentials {
clientBuilder = controller.SAControllerClientBuilder{
ClientConfig: restclient.AnonymousClientConfig(kubeconfig),
CoreClient: kubeClient.Core(),
AuthenticationClient: kubeClient.Authentication(),
Namespace: "kube-system",
}
} else {
clientBuilder = rootClientBuilder
}
ctx, err := CreateControllerContext(s, rootClientBuilder, clientBuilder, stop)
if err != nil {
glog.Fatalf("error building controller context: %v", err)
}
saTokenControllerInitFunc := serviceAccountTokenControllerStarter{rootClientBuilder: rootClientBuilder}.startServiceAccountTokenController
if err := StartControllers(ctx, saTokenControllerInitFunc, NewControllerInitializers()); err != nil {
glog.Fatalf("error starting controllers: %v", err)
}
ctx.InformerFactory.Start(ctx.Stop)
select {}
}
if !s.LeaderElection.LeaderElect {
run(nil)
panic("unreachable")
}
id, err := os.Hostname()
if err != nil {
return err
}
rl, err := resourcelock.New(s.LeaderElection.ResourceLock,
"kube-system",
"kube-controller-manager",
leaderElectionClient,
resourcelock.ResourceLockConfig{
Identity: id,
EventRecorder: recorder,
})
if err != nil {
glog.Fatalf("error creating lock: %v", err)
}
leaderelection.RunOrDie(leaderelection.LeaderElectionConfig{
Lock: rl,
LeaseDuration: s.LeaderElection.LeaseDuration.Duration,
RenewDeadline: s.LeaderElection.RenewDeadline.Duration,
RetryPeriod: s.LeaderElection.RetryPeriod.Duration,
Callbacks: leaderelection.LeaderCallbacks{
OnStartedLeading: run,
OnStoppedLeading: func() {
glog.Fatalf("leaderelection lost")
},
},
})
panic("unreachable")
}
type ControllerContext struct {
// ClientBuilder will provide a client for this controller to use
ClientBuilder controller.ControllerClientBuilder
// InformerFactory gives access to informers for the controller.
InformerFactory informers.SharedInformerFactory
// Options provides access to init options for a given controller
Options options.CMServer
// AvailableResources is a map listing currently available resources
AvailableResources map[schema.GroupVersionResource]bool
// Cloud is the cloud provider interface for the controllers to use.
// It must be initialized and ready to use.
Cloud cloudprovider.Interface
// Stop is the stop channel
Stop <-chan struct{}
}
func (c ControllerContext) IsControllerEnabled(name string) bool {
return IsControllerEnabled(name, ControllersDisabledByDefault, c.Options.Controllers...)
}
func IsControllerEnabled(name string, disabledByDefaultControllers sets.String, controllers ...string) bool {
hasStar := false
for _, ctrl := range controllers {
if ctrl == name {
return true
}
if ctrl == "-"+name {
return false
}
if ctrl == "*" {
hasStar = true
}
}
// if we get here, there was no explicit choice
if !hasStar {
// nothing on by default
return false
}
if disabledByDefaultControllers.Has(name) {
return false
}
return true
}
// InitFunc is used to launch a particular controller. It may run additional "should I activate checks".
// Any error returned will cause the controller process to `Fatal`
// The bool indicates whether the controller was enabled.
type InitFunc func(ctx ControllerContext) (bool, error)
func KnownControllers() []string {
ret := sets.StringKeySet(NewControllerInitializers())
// add "special" controllers that aren't initialized normally. These controllers cannot be initialized
// using a normal function. The only known special case is the SA token controller which *must* be started
// first to ensure that the SA tokens for future controllers will exist. Think very carefully before adding
// to this list.
ret.Insert(
saTokenControllerName,
)
return ret.List()
}
var ControllersDisabledByDefault = sets.NewString(
"bootstrapsigner",
"tokencleaner",
)
const (
saTokenControllerName = "serviceaccount-token"
)
// NewControllerInitializers is a public map of named controller groups (you can start more than one in an init func)
// paired to their InitFunc. This allows for structured downstream composition and subdivision.
func NewControllerInitializers() map[string]InitFunc {
controllers := map[string]InitFunc{}
controllers["endpoint"] = startEndpointController
controllers["replicationcontroller"] = startReplicationController
controllers["podgc"] = startPodGCController
controllers["resourcequota"] = startResourceQuotaController
controllers["namespace"] = startNamespaceController
controllers["serviceaccount"] = startServiceAccountController
controllers["garbagecollector"] = startGarbageCollectorController
controllers["daemonset"] = startDaemonSetController
controllers["job"] = startJobController
controllers["deployment"] = startDeploymentController
controllers["replicaset"] = startReplicaSetController
controllers["horizontalpodautoscaling"] = startHPAController
controllers["disruption"] = startDisruptionController
controllers["statefulset"] = startStatefulSetController
controllers["cronjob"] = startCronJobController
controllers["csrsigning"] = startCSRSigningController
controllers["csrapproving"] = startCSRApprovingController
controllers["ttl"] = startTTLController
controllers["bootstrapsigner"] = startBootstrapSignerController
controllers["tokencleaner"] = startTokenCleanerController
controllers["service"] = startServiceController
controllers["node"] = startNodeController
controllers["route"] = startRouteController
controllers["persistentvolume-binder"] = startPersistentVolumeBinderController
controllers["attachdetach"] = startAttachDetachController
return controllers
}
// TODO: In general, any controller checking this needs to be dynamic so
// users don't have to restart their controller manager if they change the apiserver.
// Until we get there, the structure here needs to be exposed for the construction of a proper ControllerContext.
func GetAvailableResources(clientBuilder controller.ControllerClientBuilder) (map[schema.GroupVersionResource]bool, error) {
var discoveryClient discovery.DiscoveryInterface
// If apiserver is not running we should wait for some time and fail only then. This is particularly
// important when we start apiserver and controller manager at the same time.
err := wait.PollImmediate(time.Second, 10*time.Second, func() (bool, error) {
client, err := clientBuilder.Client("controller-discovery")
if err != nil {
glog.Errorf("Failed to get api versions from server: %v", err)
return false, nil
}
healthStatus := 0
client.Discovery().RESTClient().Get().AbsPath("/healthz").Do().StatusCode(&healthStatus)
if healthStatus != http.StatusOK {
glog.Errorf("Server isn't healthy yet. Waiting a little while.")
return false, nil
}
discoveryClient = client.Discovery()
return true, nil
})
if err != nil {
return nil, fmt.Errorf("failed to get api versions from server: %v", err)
}
resourceMap, err := discoveryClient.ServerResources()
if err != nil {
return nil, fmt.Errorf("failed to get supported resources from server: %v", err)
}
allResources := map[schema.GroupVersionResource]bool{}
for _, apiResourceList := range resourceMap {
version, err := schema.ParseGroupVersion(apiResourceList.GroupVersion)
if err != nil {
return nil, err
}
for _, apiResource := range apiResourceList.APIResources {
allResources[version.WithResource(apiResource.Name)] = true
}
}
return allResources, nil
}
func CreateControllerContext(s *options.CMServer, rootClientBuilder, clientBuilder controller.ControllerClientBuilder, stop <-chan struct{}) (ControllerContext, error) {
versionedClient := rootClientBuilder.ClientOrDie("shared-informers")
sharedInformers := informers.NewSharedInformerFactory(versionedClient, ResyncPeriod(s)())
availableResources, err := GetAvailableResources(rootClientBuilder)
if err != nil {
return ControllerContext{}, err
}
cloud, err := cloudprovider.InitCloudProvider(s.CloudProvider, s.CloudConfigFile)
if err != nil {
return ControllerContext{}, fmt.Errorf("cloud provider could not be initialized: %v", err)
}
if cloud != nil {
// Initialize the cloud provider with a reference to the clientBuilder
cloud.Initialize(rootClientBuilder)
}
ctx := ControllerContext{
ClientBuilder: clientBuilder,
InformerFactory: sharedInformers,
Options: *s,
AvailableResources: availableResources,
Cloud: cloud,
Stop: stop,
}
return ctx, nil
}
func StartControllers(ctx ControllerContext, startSATokenController InitFunc, controllers map[string]InitFunc) error {
// Always start the SA token controller first using a full-power client, since it needs to mint tokens for the rest
// If this fails, just return here and fail since other controllers won't be able to get credentials.
if _, err := startSATokenController(ctx); err != nil {
return err
}
for controllerName, initFn := range controllers {
if !ctx.IsControllerEnabled(controllerName) {
glog.Warningf("%q is disabled", controllerName)
continue
}
time.Sleep(wait.Jitter(ctx.Options.ControllerStartInterval.Duration, ControllerStartJitter))
glog.V(1).Infof("Starting %q", controllerName)
started, err := initFn(ctx)
if err != nil {
glog.Errorf("Error starting %q", controllerName)
return err
}
if !started {
glog.Warningf("Skipping %q", controllerName)
continue
}
glog.Infof("Started %q", controllerName)
}
return nil
}
// serviceAccountTokenControllerStarter is special because it must run first to set up permissions for other controllers.
// It cannot use the "normal" client builder, so it tracks its own. It must also avoid being included in the "normal"
// init map so that it can always run first.
type serviceAccountTokenControllerStarter struct {
rootClientBuilder controller.ControllerClientBuilder
}
func (c serviceAccountTokenControllerStarter) startServiceAccountTokenController(ctx ControllerContext) (bool, error) {
if !ctx.IsControllerEnabled(saTokenControllerName) {
glog.Warningf("%q is disabled", saTokenControllerName)
return false, nil
}
if len(ctx.Options.ServiceAccountKeyFile) == 0 {
glog.Warningf("%q is disabled because there is no private key", saTokenControllerName)
return false, nil
}
privateKey, err := serviceaccount.ReadPrivateKey(ctx.Options.ServiceAccountKeyFile)
if err != nil {
return true, fmt.Errorf("error reading key for service account token controller: %v", err)
}
var rootCA []byte
if ctx.Options.RootCAFile != "" {
rootCA, err = ioutil.ReadFile(ctx.Options.RootCAFile)
if err != nil {
return true, fmt.Errorf("error reading root-ca-file at %s: %v", ctx.Options.RootCAFile, err)
}
if _, err := certutil.ParseCertsPEM(rootCA); err != nil {
return true, fmt.Errorf("error parsing root-ca-file at %s: %v", ctx.Options.RootCAFile, err)
}
} else {
rootCA = c.rootClientBuilder.ConfigOrDie("tokens-controller").CAData
}
controller := serviceaccountcontroller.NewTokensController(
ctx.InformerFactory.Core().V1().ServiceAccounts(),
ctx.InformerFactory.Core().V1().Secrets(),
c.rootClientBuilder.ClientOrDie("tokens-controller"),
serviceaccountcontroller.TokensControllerOptions{
TokenGenerator: serviceaccount.JWTTokenGenerator(privateKey),
RootCA: rootCA,
},
)
go controller.Run(int(ctx.Options.ConcurrentSATokenSyncs), ctx.Stop)
// start the first set of informers now so that other controllers can start
ctx.InformerFactory.Start(ctx.Stop)
return true, nil
}