mirror of https://github.com/k3s-io/k3s
266 lines
10 KiB
Go
266 lines
10 KiB
Go
/*
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Copyright 2017 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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package kubeletconfig
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import (
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"fmt"
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"os"
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"time"
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"k8s.io/klog"
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apiv1 "k8s.io/api/core/v1"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/types"
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clientset "k8s.io/client-go/kubernetes"
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v1core "k8s.io/client-go/kubernetes/typed/core/v1"
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"k8s.io/client-go/tools/cache"
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"k8s.io/kubernetes/pkg/kubelet/kubeletconfig/checkpoint"
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"k8s.io/kubernetes/pkg/kubelet/kubeletconfig/status"
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utillog "k8s.io/kubernetes/pkg/kubelet/kubeletconfig/util/log"
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)
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const (
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// KubeletConfigChangedEventReason identifies an event as a change of Kubelet configuration
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KubeletConfigChangedEventReason = "KubeletConfigChanged"
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// LocalEventMessage is sent when the Kubelet restarts to use local config
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LocalEventMessage = "Kubelet restarting to use local config"
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// RemoteEventMessageFmt is sent when the Kubelet restarts to use a remote config
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RemoteEventMessageFmt = "Kubelet restarting to use %s, UID: %s, ResourceVersion: %s, KubeletConfigKey: %s"
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)
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// pokeConfiSourceWorker tells the worker thread that syncs config sources that work needs to be done
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func (cc *Controller) pokeConfigSourceWorker() {
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select {
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case cc.pendingConfigSource <- true:
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default:
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}
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}
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// syncConfigSource checks if work needs to be done to use a new configuration, and does that work if necessary
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func (cc *Controller) syncConfigSource(client clientset.Interface, eventClient v1core.EventsGetter, nodeName string) {
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select {
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case <-cc.pendingConfigSource:
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default:
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// no work to be done, return
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return
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}
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// if the sync fails, we want to retry
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var syncerr error
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defer func() {
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if syncerr != nil {
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utillog.Errorf(syncerr.Error())
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cc.pokeConfigSourceWorker()
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}
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}()
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// get the latest Node.Spec.ConfigSource from the informer
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source, err := latestNodeConfigSource(cc.nodeInformer.GetStore(), nodeName)
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if err != nil {
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cc.configStatus.SetErrorOverride(fmt.Sprintf(status.SyncErrorFmt, status.InternalError))
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syncerr = fmt.Errorf("%s, error: %v", status.InternalError, err)
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return
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}
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// a nil source simply means we reset to local defaults
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if source == nil {
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utillog.Infof("Node.Spec.ConfigSource is empty, will reset assigned and last-known-good to defaults")
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if updated, reason, err := cc.resetConfig(); err != nil {
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reason = fmt.Sprintf(status.SyncErrorFmt, reason)
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cc.configStatus.SetErrorOverride(reason)
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syncerr = fmt.Errorf("%s, error: %v", reason, err)
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return
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} else if updated {
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restartForNewConfig(eventClient, nodeName, nil)
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}
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return
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}
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// a non-nil source means we should attempt to download the config, and checkpoint it if necessary
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utillog.Infof("Node.Spec.ConfigSource is non-empty, will checkpoint source and update config if necessary")
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// TODO(mtaufen): It would be nice if we could check the payload's metadata before (re)downloading the whole payload
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// we at least try pulling the latest configmap out of the local informer store.
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// construct the interface that can dynamically dispatch the correct Download, etc. methods for the given source type
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remote, reason, err := checkpoint.NewRemoteConfigSource(source)
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if err != nil {
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reason = fmt.Sprintf(status.SyncErrorFmt, reason)
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cc.configStatus.SetErrorOverride(reason)
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syncerr = fmt.Errorf("%s, error: %v", reason, err)
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return
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}
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// "download" source, either from informer's in-memory store or directly from the API server, if the informer doesn't have a copy
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payload, reason, err := cc.downloadConfigPayload(client, remote)
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if err != nil {
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reason = fmt.Sprintf(status.SyncErrorFmt, reason)
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cc.configStatus.SetErrorOverride(reason)
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syncerr = fmt.Errorf("%s, error: %v", reason, err)
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return
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}
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// save a checkpoint for the payload, if one does not already exist
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if reason, err := cc.saveConfigCheckpoint(remote, payload); err != nil {
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reason = fmt.Sprintf(status.SyncErrorFmt, reason)
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cc.configStatus.SetErrorOverride(reason)
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syncerr = fmt.Errorf("%s, error: %v", reason, err)
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return
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}
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// update the local, persistent record of assigned config
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if updated, reason, err := cc.setAssignedConfig(remote); err != nil {
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reason = fmt.Sprintf(status.SyncErrorFmt, reason)
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cc.configStatus.SetErrorOverride(reason)
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syncerr = fmt.Errorf("%s, error: %v", reason, err)
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return
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} else if updated {
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restartForNewConfig(eventClient, nodeName, remote)
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}
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// If we get here:
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// - there is no need to restart to use new config
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// - there was no error trying to sync configuration
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// - if, previously, there was an error trying to sync configuration, we need to clear that error from the status
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cc.configStatus.SetErrorOverride("")
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}
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// Note: source has up-to-date uid and resourceVersion after calling downloadConfigPayload.
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func (cc *Controller) downloadConfigPayload(client clientset.Interface, source checkpoint.RemoteConfigSource) (checkpoint.Payload, string, error) {
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var store cache.Store
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if cc.remoteConfigSourceInformer != nil {
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store = cc.remoteConfigSourceInformer.GetStore()
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}
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return source.Download(client, store)
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}
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func (cc *Controller) saveConfigCheckpoint(source checkpoint.RemoteConfigSource, payload checkpoint.Payload) (string, error) {
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ok, err := cc.checkpointStore.Exists(source)
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if err != nil {
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return status.InternalError, fmt.Errorf("%s, error: %v", status.InternalError, err)
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}
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if ok {
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utillog.Infof("checkpoint already exists for %s, UID: %s, ResourceVersion: %s", source.APIPath(), payload.UID(), payload.ResourceVersion())
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return "", nil
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}
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if err := cc.checkpointStore.Save(payload); err != nil {
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return status.InternalError, fmt.Errorf("%s, error: %v", status.InternalError, err)
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}
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return "", nil
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}
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// setAssignedConfig updates the assigned checkpoint config in the store.
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// Returns whether the assigned config changed as a result, or a sanitized failure reason and an error.
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func (cc *Controller) setAssignedConfig(source checkpoint.RemoteConfigSource) (bool, string, error) {
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assigned, err := cc.checkpointStore.Assigned()
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if err != nil {
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return false, status.InternalError, err
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}
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if err := cc.checkpointStore.SetAssigned(source); err != nil {
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return false, status.InternalError, err
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}
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return !checkpoint.EqualRemoteConfigSources(assigned, source), "", nil
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}
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// resetConfig resets the assigned and last-known-good checkpoints in the checkpoint store to their default values and
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// returns whether the assigned checkpoint changed as a result, or a sanitized failure reason and an error.
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func (cc *Controller) resetConfig() (bool, string, error) {
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updated, err := cc.checkpointStore.Reset()
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if err != nil {
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return false, status.InternalError, err
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}
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return updated, "", nil
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}
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// restartForNewConfig presumes the Kubelet is managed by a babysitter, e.g. systemd
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// It will send an event before exiting.
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func restartForNewConfig(eventClient v1core.EventsGetter, nodeName string, source checkpoint.RemoteConfigSource) {
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message := LocalEventMessage
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if source != nil {
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message = fmt.Sprintf(RemoteEventMessageFmt, source.APIPath(), source.UID(), source.ResourceVersion(), source.KubeletFilename())
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}
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// we directly log and send the event, instead of using the event recorder,
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// because the event recorder won't flush its queue before we exit (we'd lose the event)
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event := makeEvent(nodeName, apiv1.EventTypeNormal, KubeletConfigChangedEventReason, message)
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klog.V(3).Infof("Event(%#v): type: '%v' reason: '%v' %v", event.InvolvedObject, event.Type, event.Reason, event.Message)
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if _, err := eventClient.Events(apiv1.NamespaceDefault).Create(event); err != nil {
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utillog.Errorf("failed to send event, error: %v", err)
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}
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utillog.Infof(message)
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os.Exit(0)
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}
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// latestNodeConfigSource returns a copy of the most recent NodeConfigSource from the Node with `nodeName` in `store`
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func latestNodeConfigSource(store cache.Store, nodeName string) (*apiv1.NodeConfigSource, error) {
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obj, ok, err := store.GetByKey(nodeName)
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if err != nil {
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err := fmt.Errorf("failed to retrieve Node %q from informer's store, error: %v", nodeName, err)
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utillog.Errorf(err.Error())
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return nil, err
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} else if !ok {
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err := fmt.Errorf("Node %q does not exist in the informer's store, can't sync config source", nodeName)
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utillog.Errorf(err.Error())
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return nil, err
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}
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node, ok := obj.(*apiv1.Node)
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if !ok {
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err := fmt.Errorf("failed to cast object from informer's store to Node, can't sync config source for Node %q", nodeName)
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utillog.Errorf(err.Error())
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return nil, err
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}
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// Copy the source, so anyone who modifies it after here doesn't mess up the informer's store!
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// This was previously the cause of a bug that made the Kubelet frequently resync config; Download updated
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// the UID and ResourceVersion on the NodeConfigSource, but the pointer was still drilling all the way
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// into the informer's copy!
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return node.Spec.ConfigSource.DeepCopy(), nil
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}
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// makeEvent constructs an event
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// similar to makeEvent in k8s.io/client-go/tools/record/event.go
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func makeEvent(nodeName, eventtype, reason, message string) *apiv1.Event {
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const componentKubelet = "kubelet"
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// NOTE(mtaufen): This is consistent with pkg/kubelet/kubelet.go. Even though setting the node
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// name as the UID looks strange, it appears to be conventional for events sent by the Kubelet.
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ref := apiv1.ObjectReference{
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Kind: "Node",
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Name: nodeName,
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UID: types.UID(nodeName),
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Namespace: "",
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}
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t := metav1.Time{Time: time.Now()}
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namespace := ref.Namespace
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if namespace == "" {
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namespace = metav1.NamespaceDefault
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}
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return &apiv1.Event{
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ObjectMeta: metav1.ObjectMeta{
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Name: fmt.Sprintf("%v.%x", ref.Name, t.UnixNano()),
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Namespace: namespace,
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},
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InvolvedObject: ref,
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Reason: reason,
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Message: message,
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FirstTimestamp: t,
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LastTimestamp: t,
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Count: 1,
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Type: eventtype,
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Source: apiv1.EventSource{Component: componentKubelet, Host: string(nodeName)},
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}
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}
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