2022-03-22 k8s的pvController的处理流程

摘要:

记录k8s的pv-controller的核心处理

参考:

从零开始入门 K8s | Kubernetes 存储架构及插件使用 - 知乎

核心处理:

入口Run

// Run starts all of this controller's control loops
func (ctrl *PersistentVolumeController) Run(ctx context.Context) {
	defer utilruntime.HandleCrash()
	defer ctrl.claimQueue.ShutDown()
	defer ctrl.volumeQueue.ShutDown()

	klog.Infof("Starting persistent volume controller")
	defer klog.Infof("Shutting down persistent volume controller")

	if !cache.WaitForNamedCacheSync("persistent volume", ctx.Done(), ctrl.volumeListerSynced, ctrl.claimListerSynced, ctrl.classListerSynced, ctrl.podListerSynced, ctrl.NodeListerSynced) {
		return
	}

	ctrl.initializeCaches(ctrl.volumeLister, ctrl.claimLister)

	go wait.Until(ctrl.resync, ctrl.resyncPeriod, ctx.Done())
	go wait.UntilWithContext(ctx, ctrl.volumeWorker, time.Second)
	go wait.UntilWithContext(ctx, ctrl.claimWorker, time.Second)

	metrics.Register(ctrl.volumes.store, ctrl.claims, &ctrl.volumePluginMgr)

	<-ctx.Done()
}

volumeWorker

// volumeWorker processes items from volumeQueue. It must run only once,
// syncVolume is not assured to be reentrant.
func (ctrl *PersistentVolumeController) volumeWorker(ctx context.Context) {
	workFunc := func(ctx context.Context) bool {
		keyObj, quit := ctrl.volumeQueue.Get()
		if quit {
			return true
		}
		defer ctrl.volumeQueue.Done(keyObj)
		key := keyObj.(string)
		klog.V(5).Infof("volumeWorker[%s]", key)

		_, name, err := cache.SplitMetaNamespaceKey(key)
		if err != nil {
			klog.V(4).Infof("error getting name of volume %q to get volume from informer: %v", key, err)
			return false
		}
		volume, err := ctrl.volumeLister.Get(name)
		if err == nil {
			// The volume still exists in informer cache, the event must have
			// been add/update/sync
			ctrl.updateVolume(ctx, volume)
			return false
		}
		if !errors.IsNotFound(err) {
			klog.V(2).Infof("error getting volume %q from informer: %v", key, err)
			return false
		}

		// The volume is not in informer cache, the event must have been
		// "delete"
		volumeObj, found, err := ctrl.volumes.store.GetByKey(key)
		if err != nil {
			klog.V(2).Infof("error getting volume %q from cache: %v", key, err)
			return false
		}
		if !found {
			// The controller has already processed the delete event and
			// deleted the volume from its cache
			klog.V(2).Infof("deletion of volume %q was already processed", key)
			return false
		}
		volume, ok := volumeObj.(*v1.PersistentVolume)
		if !ok {
			klog.Errorf("expected volume, got %+v", volumeObj)
			return false
		}
		ctrl.deleteVolume(volume)
		return false
	}
	for {
		if quit := workFunc(ctx); quit {
			klog.Infof("volume worker queue shutting down")
			return
		}
	}
}

// updateIndices modifies the objects location in the managed indexes:
// - for create you must provide only the newObj
// - for update you must provide both the oldObj and the newObj
// - for delete you must provide only the oldObj
// updateIndices must be called from a function that already has a lock on the cache
func (c *threadSafeMap) updateIndices(oldObj interface{}, newObj interface{}, key string) {
	var oldIndexValues, indexValues []string
	var err error
	for name, indexFunc := range c.indexers {
		if oldObj != nil {
			oldIndexValues, err = indexFunc(oldObj)
		} else {
			oldIndexValues = oldIndexValues[:0]
		}
		if err != nil {
			panic(fmt.Errorf("unable to calculate an index entry for key %q on index %q: %v", key, name, err))
		}

		if newObj != nil {
			indexValues, err = indexFunc(newObj)
		} else {
			indexValues = indexValues[:0]
		}
		if err != nil {
			panic(fmt.Errorf("unable to calculate an index entry for key %q on index %q: %v", key, name, err))
		}

		index := c.indices[name]
		if index == nil {
			index = Index{}
			c.indices[name] = index
		}

		for _, value := range oldIndexValues {
			// We optimize for the most common case where index returns a single value.
			if len(indexValues) == 1 && value == indexValues[0] {
				continue
			}
			c.deleteKeyFromIndex(key, value, index)
		}
		for _, value := range indexValues {
			// We optimize for the most common case where index returns a single value.
			if len(oldIndexValues) == 1 && value == oldIndexValues[0] {
				continue
			}
			c.addKeyToIndex(key, value, index)
		}
	}
}

claimWorker

// claimWorker processes items from claimQueue. It must run only once,
// syncClaim is not reentrant.
func (ctrl *PersistentVolumeController) claimWorker(ctx context.Context) {
	workFunc := func() bool {
		keyObj, quit := ctrl.claimQueue.Get()
		if quit {
			return true
		}
		defer ctrl.claimQueue.Done(keyObj)
		key := keyObj.(string)
		klog.V(5).Infof("claimWorker[%s]", key)

		namespace, name, err := cache.SplitMetaNamespaceKey(key)
		if err != nil {
			klog.V(4).Infof("error getting namespace & name of claim %q to get claim from informer: %v", key, err)
			return false
		}
		claim, err := ctrl.claimLister.PersistentVolumeClaims(namespace).Get(name)
		if err == nil {
			// The claim still exists in informer cache, the event must have
			// been add/update/sync
			ctrl.updateClaim(ctx, claim)
			return false
		}
		if !errors.IsNotFound(err) {
			klog.V(2).Infof("error getting claim %q from informer: %v", key, err)
			return false
		}

		// The claim is not in informer cache, the event must have been "delete"
		claimObj, found, err := ctrl.claims.GetByKey(key)
		if err != nil {
			klog.V(2).Infof("error getting claim %q from cache: %v", key, err)
			return false
		}
		if !found {
			// The controller has already processed the delete event and
			// deleted the claim from its cache
			klog.V(2).Infof("deletion of claim %q was already processed", key)
			return false
		}
		claim, ok := claimObj.(*v1.PersistentVolumeClaim)
		if !ok {
			klog.Errorf("expected claim, got %+v", claimObj)
			return false
		}
		ctrl.deleteClaim(claim)
		return false
	}
	for {
		if quit := workFunc(); quit {
			klog.Infof("claim worker queue shutting down")
			return
		}
	}
}