external-resizer 源码分析 -pvc 扩容分析

// pkg/controller/controller.go
// Run starts the controller.func (ctrl *resizeController) Run(  workers int, ctx context.Context) {  defer ctrl.claimQueue.ShutDown()
  klog.Infof("Starting external resizer %s", ctrl.name)  defer klog.Infof("Shutting down external resizer %s", ctrl.name)
  stopCh := ctx.Done()
  if !cache.WaitForCacheSync(stopCh, ctrl.pvSynced, ctrl.pvcSynced) {    klog.Errorf("Cannot sync pv/pvc caches")    return  }
  for i := 0; i < workers; i++ {    go wait.Until(ctrl.syncPVCs, 0, stopCh)  }
  <-stopCh}

// syncPVCs is the main worker.func (ctrl *resizeController) syncPVCs() {  key, quit := ctrl.claimQueue.Get()  if quit {    return  }  defer ctrl.claimQueue.Done(key)
  if err := ctrl.syncPVC(key.(string)); err != nil {    // Put PVC back to the queue so that we can retry later.    ctrl.claimQueue.AddRateLimited(key)  } else {    ctrl.claimQueue.Forget(key)  }}

// syncPVC checks if a pvc requests resizing, and execute the resize operation if requested.func (ctrl *resizeController) syncPVC(key string) error {  klog.V(4).Infof("Started PVC processing %q", key)
  namespace, name, err := cache.SplitMetaNamespaceKey(key)  if err != nil {    klog.Errorf("Split meta namespace key of pvc %s failed: %v", key, err)    return err  }
  pvc, err := ctrl.pvcLister.PersistentVolumeClaims(namespace).Get(name)  if err != nil {    if k8serrors.IsNotFound(err) {      klog.V(3).Infof("PVC %s/%s is deleted, no need to process it", namespace, name)      return nil    }    klog.Errorf("Get PVC %s/%s failed: %v", namespace, name, err)    return err  }
  if !ctrl.pvcNeedResize(pvc) {    klog.V(4).Infof("No need to resize PVC %q", util.PVCKey(pvc))    return nil  }
  pv, err := ctrl.pvLister.Get(pvc.Spec.VolumeName)  if err != nil {    if k8serrors.IsNotFound(err) {      klog.V(3).Infof("PV %s is deleted, no need to process it", pvc.Spec.VolumeName)      return nil    }    klog.Errorf("Get PV %q of pvc %q failed: %v", pvc.Spec.VolumeName, util.PVCKey(pvc), err)    return err  }
  if !ctrl.pvNeedResize(pvc, pv) {    klog.V(4).Infof("No need to resize PV %q", pv.Name)    return nil  }
  return ctrl.resizePVC(pvc, pv)}

// pvcNeedResize returns true is a pvc requests a resize operation.func (ctrl *resizeController) pvcNeedResize(pvc *v1.PersistentVolumeClaim) bool {  // Only Bound pvc can be expanded.  if pvc.Status.Phase != v1.ClaimBound {    return false  }  if pvc.Spec.VolumeName == "" {    return false  }  actualSize := pvc.Status.Capacity[v1.ResourceStorage]  requestSize := pvc.Spec.Resources.Requests[v1.ResourceStorage]  return requestSize.Cmp(actualSize) > 0}

// pvNeedResize returns true if a pv supports and also requests resize.func (ctrl *resizeController) pvNeedResize(pvc *v1.PersistentVolumeClaim, pv *v1.PersistentVolume) bool {  if !ctrl.resizer.CanSupport(pv, pvc) {    klog.V(4).Infof("Resizer %q doesn't support PV %q", ctrl.name, pv.Name)    return false  }
  if (pv.Spec.ClaimRef == nil) || (pvc.Namespace != pv.Spec.ClaimRef.Namespace) || (pvc.UID != pv.Spec.ClaimRef.UID) {    klog.V(4).Infof("persistent volume is not bound to PVC being updated: %s", util.PVCKey(pvc))    return false  }
  pvSize := pv.Spec.Capacity[v1.ResourceStorage]  requestSize := pvc.Spec.Resources.Requests[v1.ResourceStorage]  if pvSize.Cmp(requestSize) >= 0 {    // If PV size is equal or bigger than request size, that means we have already resized PV.    // In this case we need to check PVC's condition.    // 1. If PVC in PersistentVolumeClaimResizing condition, we should continue to perform the    //    resizing operation as we need to know if file system resize if required. (What's more,    //    we hope the driver can find that the actual size already matched the request size and do nothing).    // 2. If PVC in PersistentVolumeClaimFileSystemResizePending condition, we need to    //    do nothing as kubelet will finish file system resizing and mark resize as finished.    if util.HasFileSystemResizePendingCondition(pvc) {      // This is case 2.      return false    }    // This is case 1.    return true  }
  // PV size is smaller than request size, we need to resize the volume.  return true}

const (  // PersistentVolumeClaimFileSystemResizePending - controller resize is finished and a file system resize is pending on node  PersistentVolumeClaimFileSystemResizePending PersistentVolumeClaimConditionType = "FileSystemResizePending")

// HasFileSystemResizePendingCondition returns true if a pvc has a FileSystemResizePending condition.// This means the controller side resize operation is finished, and kublete side operation is in progress.func HasFileSystemResizePendingCondition(pvc *v1.PersistentVolumeClaim) bool {  for _, condition := range pvc.Status.Conditions {    if condition.Type == v1.PersistentVolumeClaimFileSystemResizePending && condition.Status == v1.ConditionTrue {      return true    }  }  return false}

// resizePVC will:// 1. Mark pvc as resizing.// 2. Resize the volume and the pv object.// 3. Mark pvc as resizing finished(no error, no need to resize fs), need resizing fs or resize failed.func (ctrl *resizeController) resizePVC(pvc *v1.PersistentVolumeClaim, pv *v1.PersistentVolume) error {  if updatedPVC, err := ctrl.markPVCResizeInProgress(pvc); err != nil {    klog.Errorf("Mark pvc %q as resizing failed: %v", util.PVCKey(pvc), err)    return err  } else if updatedPVC != nil {    pvc = updatedPVC  }
  // Record an event to indicate that external resizer is resizing this volume.  ctrl.eventRecorder.Event(pvc, v1.EventTypeNormal, util.VolumeResizing,    fmt.Sprintf("External resizer is resizing volume %s", pv.Name))
  err := func() error {    newSize, fsResizeRequired, err := ctrl.resizeVolume(pvc, pv)    if err != nil {      return err    }
    if fsResizeRequired {      // Resize volume succeeded and need to resize file system by kubelet, mark it as file system resizing required.      return ctrl.markPVCAsFSResizeRequired(pvc)    }    // Resize volume succeeded and no need to resize file system by kubelet, mark it as resizing finished.    return ctrl.markPVCResizeFinished(pvc, newSize)  }()
  if err != nil {    // Record an event to indicate that resize operation is failed.    ctrl.eventRecorder.Eventf(pvc, v1.EventTypeWarning, util.VolumeResizeFailed, err.Error())  }
  return err}

// resizeVolume resize the volume to request size, and update PV's capacity if succeeded.func (ctrl *resizeController) resizeVolume(  pvc *v1.PersistentVolumeClaim,  pv *v1.PersistentVolume) (resource.Quantity, bool, error) {  requestSize := pvc.Spec.Resources.Requests[v1.ResourceStorage]
  newSize, fsResizeRequired, err := ctrl.resizer.Resize(pv, requestSize)
  if err != nil {    klog.Errorf("Resize volume %q by resizer %q failed: %v", pv.Name, ctrl.name, err)    return newSize, fsResizeRequired, fmt.Errorf("resize volume %s failed: %v", pv.Name, err)  }  klog.V(4).Infof("Resize volume succeeded for volume %q, start to update PV's capacity", pv.Name)
  if err := util.UpdatePVCapacity(pv, newSize, ctrl.kubeClient); err != nil {    klog.Errorf("Update capacity of PV %q to %s failed: %v", pv.Name, newSize.String(), err)    return newSize, fsResizeRequired, err  }  klog.V(4).Infof("Update capacity of PV %q to %s succeeded", pv.Name, newSize.String())
  return newSize, fsResizeRequired, nil}

// Resize resizes the persistence volume given request size// It supports both CSI volume and migrated in-tree volumefunc (r *csiResizer) Resize(pv *v1.PersistentVolume, requestSize resource.Quantity) (resource.Quantity, bool, error) {  oldSize := pv.Spec.Capacity[v1.ResourceStorage]
  var volumeID string  var source *v1.CSIPersistentVolumeSource  var pvSpec v1.PersistentVolumeSpec  if pv.Spec.CSI != nil {    // handle CSI volume    source = pv.Spec.CSI    volumeID = source.VolumeHandle    pvSpec = pv.Spec  } else {    if csitranslationlib.IsMigratedCSIDriverByName(r.name) {      // handle migrated in-tree volume      csiPV, err := csitranslationlib.TranslateInTreePVToCSI(pv)      if err != nil {        return oldSize, false, fmt.Errorf("failed to translate persistent volume: %v", err)      }      source = csiPV.Spec.CSI      pvSpec = csiPV.Spec      volumeID = source.VolumeHandle    } else {      // non-migrated in-tree volume      return oldSize, false, fmt.Errorf("volume %v is not migrated to CSI", pv.Name)    }  }
  if len(volumeID) == 0 {    return oldSize, false, errors.New("empty volume handle")  }
  var secrets map[string]string  secreRef := source.ControllerExpandSecretRef  if secreRef != nil {    var err error    secrets, err = getCredentials(r.k8sClient, secreRef)    if err != nil {      return oldSize, false, err    }  }
  secrets[pvCephMountPathKey] = pv.Annotations[pvCephMountPathKey]
  capability, err := GetVolumeCapabilities(pvSpec)  if err != nil {    return oldSize, false, fmt.Errorf("failed to get capabilities of volume %s with %v", pv.Name, err)  }
  ctx, cancel := timeoutCtx(r.timeout)  defer cancel()  newSizeBytes, nodeResizeRequired, err := r.client.Expand(ctx, volumeID, requestSize.Value(), secrets, capability)  if err != nil {    return oldSize, nodeResizeRequired, err  }
  return *resource.NewQuantity(newSizeBytes, resource.BinarySI), nodeResizeRequired, err}

// pkg/csi/client.gofunc (c *client) Expand(  ctx context.Context,  volumeID string,  requestBytes int64,  secrets map[string]string,  capability *csi.VolumeCapability) (int64, bool, error) {  req := &csi.ControllerExpandVolumeRequest{    Secrets:          secrets,    VolumeId:         volumeID,    CapacityRange:    &csi.CapacityRange{RequiredBytes: requestBytes},    VolumeCapability: capability,  }  resp, err := c.ctrlClient.ControllerExpandVolume(ctx, req)  if err != nil {    return 0, false, err  }  return resp.CapacityBytes, resp.NodeExpansionRequired, nil}

// UpdatePVCapacity updates PVC capacity with requested size.func UpdatePVCapacity(pv *v1.PersistentVolume, newCapacity resource.Quantity, kubeClient kubernetes.Interface) error {  newPV := pv.DeepCopy()  newPV.Spec.Capacity[v1.ResourceStorage] = newCapacity  patchBytes, err := getPatchData(pv, newPV)  if err != nil {    return fmt.Errorf("can't update capacity of PV %s as generate path data failed: %v", pv.Name, err)  }  _, updateErr := kubeClient.CoreV1().PersistentVolumes().Patch(pv.Name, types.StrategicMergePatchType, patchBytes)  if updateErr != nil {    return fmt.Errorf("update capacity of PV %s failed: %v", pv.Name, updateErr)  }  return nil}