371 lines
12 KiB
Go
371 lines
12 KiB
Go
/*
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Copyright 2016 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 statefulset
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import (
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"fmt"
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"reflect"
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"sort"
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"time"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/kubernetes/pkg/api/v1"
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apps "k8s.io/kubernetes/pkg/apis/apps/v1beta1"
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"k8s.io/kubernetes/pkg/client/cache"
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"k8s.io/kubernetes/pkg/client/clientset_generated/clientset"
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v1core "k8s.io/kubernetes/pkg/client/clientset_generated/clientset/typed/core/v1"
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"k8s.io/kubernetes/pkg/client/legacylisters"
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"k8s.io/kubernetes/pkg/client/record"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/util/errors"
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utilruntime "k8s.io/apimachinery/pkg/util/runtime"
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"k8s.io/apimachinery/pkg/util/wait"
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"k8s.io/apimachinery/pkg/watch"
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"k8s.io/kubernetes/pkg/controller"
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"k8s.io/kubernetes/pkg/util/workqueue"
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"github.com/golang/glog"
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)
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const (
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// Time to sleep before polling to see if the pod cache has synced.
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PodStoreSyncedPollPeriod = 100 * time.Millisecond
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// number of retries for a status update.
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statusUpdateRetries = 2
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// period to relist statefulsets and verify pets
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statefulSetResyncPeriod = 30 * time.Second
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)
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// StatefulSetController controls statefulsets.
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type StatefulSetController struct {
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kubeClient clientset.Interface
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// newSyncer returns an interface capable of syncing a single pet.
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// Abstracted out for testing.
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newSyncer func(*pcb) *petSyncer
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// podStore is a cache of watched pods.
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podStore listers.StoreToPodLister
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// podStoreSynced returns true if the pod store has synced at least once.
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podStoreSynced func() bool
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// Watches changes to all pods.
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podController cache.Controller
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// A store of StatefulSets, populated by the psController.
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psStore listers.StoreToStatefulSetLister
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// Watches changes to all StatefulSets.
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psController cache.Controller
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// A store of the 1 unhealthy pet blocking progress for a given ps
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blockingPetStore *unhealthyPetTracker
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// Controllers that need to be synced.
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queue workqueue.RateLimitingInterface
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// syncHandler handles sync events for statefulsets.
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// Abstracted as a func to allow injection for testing.
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syncHandler func(psKey string) error
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}
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// NewStatefulSetController creates a new statefulset controller.
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func NewStatefulSetController(podInformer cache.SharedIndexInformer, kubeClient clientset.Interface, resyncPeriod time.Duration) *StatefulSetController {
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eventBroadcaster := record.NewBroadcaster()
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eventBroadcaster.StartLogging(glog.Infof)
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eventBroadcaster.StartRecordingToSink(&v1core.EventSinkImpl{Interface: kubeClient.Core().Events("")})
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recorder := eventBroadcaster.NewRecorder(v1.EventSource{Component: "statefulset"})
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pc := &apiServerPetClient{kubeClient, recorder, &defaultPetHealthChecker{}}
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psc := &StatefulSetController{
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kubeClient: kubeClient,
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blockingPetStore: newUnHealthyPetTracker(pc),
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newSyncer: func(blockingPet *pcb) *petSyncer {
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return &petSyncer{pc, blockingPet}
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},
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queue: workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "statefulset"),
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}
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podInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
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// lookup the statefulset and enqueue
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AddFunc: psc.addPod,
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// lookup current and old statefulset if labels changed
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UpdateFunc: psc.updatePod,
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// lookup statefulset accounting for deletion tombstones
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DeleteFunc: psc.deletePod,
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})
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psc.podStore.Indexer = podInformer.GetIndexer()
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psc.podController = podInformer.GetController()
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psc.psStore.Store, psc.psController = cache.NewInformer(
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&cache.ListWatch{
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ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
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return psc.kubeClient.Apps().StatefulSets(metav1.NamespaceAll).List(options)
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},
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WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
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return psc.kubeClient.Apps().StatefulSets(metav1.NamespaceAll).Watch(options)
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},
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},
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&apps.StatefulSet{},
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statefulSetResyncPeriod,
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cache.ResourceEventHandlerFuncs{
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AddFunc: psc.enqueueStatefulSet,
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UpdateFunc: func(old, cur interface{}) {
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oldPS := old.(*apps.StatefulSet)
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curPS := cur.(*apps.StatefulSet)
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if oldPS.Status.Replicas != curPS.Status.Replicas {
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glog.V(4).Infof("Observed updated replica count for StatefulSet: %v, %d->%d", curPS.Name, oldPS.Status.Replicas, curPS.Status.Replicas)
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}
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psc.enqueueStatefulSet(cur)
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},
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DeleteFunc: psc.enqueueStatefulSet,
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},
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)
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// TODO: Watch volumes
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psc.podStoreSynced = psc.podController.HasSynced
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psc.syncHandler = psc.Sync
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return psc
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}
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// Run runs the statefulset controller.
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func (psc *StatefulSetController) Run(workers int, stopCh <-chan struct{}) {
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defer utilruntime.HandleCrash()
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glog.Infof("Starting statefulset controller")
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go psc.podController.Run(stopCh)
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go psc.psController.Run(stopCh)
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for i := 0; i < workers; i++ {
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go wait.Until(psc.worker, time.Second, stopCh)
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}
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<-stopCh
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glog.Infof("Shutting down statefulset controller")
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psc.queue.ShutDown()
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}
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// addPod adds the statefulset for the pod to the sync queue
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func (psc *StatefulSetController) addPod(obj interface{}) {
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pod := obj.(*v1.Pod)
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glog.V(4).Infof("Pod %s created, labels: %+v", pod.Name, pod.Labels)
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ps := psc.getStatefulSetForPod(pod)
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if ps == nil {
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return
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}
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psc.enqueueStatefulSet(ps)
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}
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// updatePod adds the statefulset for the current and old pods to the sync queue.
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// If the labels of the pod didn't change, this method enqueues a single statefulset.
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func (psc *StatefulSetController) updatePod(old, cur interface{}) {
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curPod := cur.(*v1.Pod)
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oldPod := old.(*v1.Pod)
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if curPod.ResourceVersion == oldPod.ResourceVersion {
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// Periodic resync will send update events for all known pods.
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// Two different versions of the same pod will always have different RVs.
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return
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}
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ps := psc.getStatefulSetForPod(curPod)
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if ps == nil {
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return
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}
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psc.enqueueStatefulSet(ps)
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if !reflect.DeepEqual(curPod.Labels, oldPod.Labels) {
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if oldPS := psc.getStatefulSetForPod(oldPod); oldPS != nil {
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psc.enqueueStatefulSet(oldPS)
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}
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}
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}
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// deletePod enqueues the statefulset for the pod accounting for deletion tombstones.
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func (psc *StatefulSetController) deletePod(obj interface{}) {
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pod, ok := obj.(*v1.Pod)
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// When a delete is dropped, the relist will notice a pod in the store not
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// in the list, leading to the insertion of a tombstone object which contains
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// the deleted key/value. Note that this value might be stale. If the pod
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// changed labels the new StatefulSet will not be woken up till the periodic resync.
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if !ok {
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tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
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if !ok {
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glog.Errorf("couldn't get object from tombstone %+v", obj)
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return
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}
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pod, ok = tombstone.Obj.(*v1.Pod)
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if !ok {
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glog.Errorf("tombstone contained object that is not a pod %+v", obj)
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return
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}
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}
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glog.V(4).Infof("Pod %s/%s deleted through %v.", pod.Namespace, pod.Name, utilruntime.GetCaller())
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if ps := psc.getStatefulSetForPod(pod); ps != nil {
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psc.enqueueStatefulSet(ps)
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}
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}
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// getPodsForStatefulSets returns the pods that match the selectors of the given statefulset.
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func (psc *StatefulSetController) getPodsForStatefulSet(ps *apps.StatefulSet) ([]*v1.Pod, error) {
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// TODO: Do we want the statefulset to fight with RCs? check parent statefulset annotation, or name prefix?
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sel, err := metav1.LabelSelectorAsSelector(ps.Spec.Selector)
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if err != nil {
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return []*v1.Pod{}, err
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}
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pods, err := psc.podStore.Pods(ps.Namespace).List(sel)
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if err != nil {
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return []*v1.Pod{}, err
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}
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// TODO: Do we need to copy?
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result := make([]*v1.Pod, 0, len(pods))
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for i := range pods {
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result = append(result, &(*pods[i]))
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}
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return result, nil
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}
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// getStatefulSetForPod returns the pet set managing the given pod.
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func (psc *StatefulSetController) getStatefulSetForPod(pod *v1.Pod) *apps.StatefulSet {
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ps, err := psc.psStore.GetPodStatefulSets(pod)
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if err != nil {
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glog.V(4).Infof("No StatefulSets found for pod %v, StatefulSet controller will avoid syncing", pod.Name)
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return nil
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}
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// Resolve a overlapping statefulset tie by creation timestamp.
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// Let's hope users don't create overlapping statefulsets.
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if len(ps) > 1 {
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glog.Errorf("user error! more than one StatefulSet is selecting pods with labels: %+v", pod.Labels)
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sort.Sort(overlappingStatefulSets(ps))
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}
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return &ps[0]
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}
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// enqueueStatefulSet enqueues the given statefulset in the work queue.
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func (psc *StatefulSetController) enqueueStatefulSet(obj interface{}) {
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key, err := controller.KeyFunc(obj)
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if err != nil {
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glog.Errorf("Cound't get key for object %+v: %v", obj, err)
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return
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}
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psc.queue.Add(key)
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}
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// worker runs a worker thread that just dequeues items, processes them, and marks them done.
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// It enforces that the syncHandler is never invoked concurrently with the same key.
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func (psc *StatefulSetController) worker() {
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for {
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func() {
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key, quit := psc.queue.Get()
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if quit {
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return
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}
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defer psc.queue.Done(key)
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if err := psc.syncHandler(key.(string)); err != nil {
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glog.Errorf("Error syncing StatefulSet %v, requeuing: %v", key.(string), err)
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psc.queue.AddRateLimited(key)
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} else {
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psc.queue.Forget(key)
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}
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}()
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}
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}
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// Sync syncs the given statefulset.
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func (psc *StatefulSetController) Sync(key string) error {
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startTime := time.Now()
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defer func() {
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glog.V(4).Infof("Finished syncing statefulset %q (%v)", key, time.Now().Sub(startTime))
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}()
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if !psc.podStoreSynced() {
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// Sleep so we give the pod reflector goroutine a chance to run.
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time.Sleep(PodStoreSyncedPollPeriod)
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return fmt.Errorf("waiting for pods controller to sync")
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}
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obj, exists, err := psc.psStore.Store.GetByKey(key)
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if !exists {
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if err = psc.blockingPetStore.store.Delete(key); err != nil {
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return err
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}
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glog.Infof("StatefulSet has been deleted %v", key)
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return nil
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}
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if err != nil {
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glog.Errorf("Unable to retrieve StatefulSet %v from store: %v", key, err)
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return err
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}
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ps := *obj.(*apps.StatefulSet)
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petList, err := psc.getPodsForStatefulSet(&ps)
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if err != nil {
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return err
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}
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numPets, syncErr := psc.syncStatefulSet(&ps, petList)
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if updateErr := updatePetCount(psc.kubeClient.Apps(), ps, numPets); updateErr != nil {
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glog.Infof("Failed to update replica count for statefulset %v/%v; requeuing; error: %v", ps.Namespace, ps.Name, updateErr)
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return errors.NewAggregate([]error{syncErr, updateErr})
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}
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return syncErr
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}
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// syncStatefulSet syncs a tuple of (statefulset, pets).
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func (psc *StatefulSetController) syncStatefulSet(ps *apps.StatefulSet, pets []*v1.Pod) (int, error) {
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glog.V(2).Infof("Syncing StatefulSet %v/%v with %d pods", ps.Namespace, ps.Name, len(pets))
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it := NewStatefulSetIterator(ps, pets)
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blockingPet, err := psc.blockingPetStore.Get(ps, pets)
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if err != nil {
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return 0, err
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}
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if blockingPet != nil {
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glog.Infof("StatefulSet %v blocked from scaling on pod %v", ps.Name, blockingPet.pod.Name)
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}
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petManager := psc.newSyncer(blockingPet)
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numPets := 0
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for it.Next() {
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pet := it.Value()
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if pet == nil {
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continue
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}
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switch pet.event {
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case syncPet:
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err = petManager.Sync(pet)
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if err == nil {
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numPets++
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}
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case deletePet:
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err = petManager.Delete(pet)
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}
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switch err.(type) {
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case errUnhealthyPet:
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// We are not passing this error up, but we don't increment numPets if we encounter it,
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// since numPets directly translates to statefulset.status.replicas
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continue
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case nil:
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continue
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default:
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it.errs = append(it.errs, err)
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}
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}
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if err := psc.blockingPetStore.Add(petManager.blockingPet); err != nil {
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it.errs = append(it.errs, err)
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}
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// TODO: GC pvcs. We can't delete them per pet because of grace period, and
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// in fact we *don't want to* till statefulset is stable to guarantee that bugs
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// in the controller don't corrupt user data.
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return numPets, errors.NewAggregate(it.errs)
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}
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