Replicate the persistent volume label admission plugin in a controller in

the cloud-controller-manager

pkg/controller/cloud/pvlcontroller.go

@@ -0,0 +1,373 @@
+/*
+Copyright 2017 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 cloud
+
+import (
+	"encoding/json"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/golang/glog"
+
+	"k8s.io/api/core/v1"
+
+	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/types"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/apimachinery/pkg/util/strategicpatch"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/apimachinery/pkg/watch"
+
+	"k8s.io/client-go/kubernetes"
+	corelisters "k8s.io/client-go/listers/core/v1"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/client-go/util/workqueue"
+
+	"k8s.io/kubernetes/pkg/cloudprovider"
+	"k8s.io/kubernetes/pkg/cloudprovider/providers/aws"
+	"k8s.io/kubernetes/pkg/cloudprovider/providers/gce"
+	"k8s.io/kubernetes/pkg/controller"
+	kubeletapis "k8s.io/kubernetes/pkg/kubelet/apis"
+	vol "k8s.io/kubernetes/pkg/volume"
+)
+
+const initializerName = "pvlabel.kubernetes.io"
+
+// PersistentVolumeLabelController handles adding labels to persistent volumes when they are created
+type PersistentVolumeLabelController struct {
+	// Control access to cloud volumes
+	mutex            sync.Mutex
+	ebsVolumes       aws.Volumes
+	gceCloudProvider *gce.GCECloud
+
+	cloud         cloudprovider.Interface
+	kubeClient    kubernetes.Interface
+	pvlController cache.Controller
+	pvlIndexer    cache.Indexer
+	volumeLister  corelisters.PersistentVolumeLister
+
+	syncHandler func(key string) error
+
+	// queue is where incoming work is placed to de-dup and to allow "easy" rate limited requeues on errors
+	queue workqueue.RateLimitingInterface
+}
+
+// NewPersistentVolumeLabelController creates a PersistentVolumeLabelController object
+func NewPersistentVolumeLabelController(
+	kubeClient kubernetes.Interface,
+	cloud cloudprovider.Interface) *PersistentVolumeLabelController {
+
+	pvlc := &PersistentVolumeLabelController{
+		cloud:      cloud,
+		kubeClient: kubeClient,
+		queue:      workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "pvLabels"),
+	}
+	pvlc.syncHandler = pvlc.addLabels
+	pvlc.pvlIndexer, pvlc.pvlController = cache.NewIndexerInformer(
+		&cache.ListWatch{
+			ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
+				options.IncludeUninitialized = true
+				return kubeClient.CoreV1().PersistentVolumes().List(options)
+			},
+			WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
+				options.IncludeUninitialized = true
+				return kubeClient.CoreV1().PersistentVolumes().Watch(options)
+			},
+		},
+		&v1.PersistentVolume{},
+		0,
+		cache.ResourceEventHandlerFuncs{
+			AddFunc: func(obj interface{}) {
+				key, err := cache.MetaNamespaceKeyFunc(obj)
+				if err == nil {
+					pvlc.queue.Add(key)
+				}
+			},
+		},
+		cache.Indexers{},
+	)
+	pvlc.volumeLister = corelisters.NewPersistentVolumeLister(pvlc.pvlIndexer)
+
+	return pvlc
+}
+
+// Run starts a controller that adds labels to persistent volumes
+func (pvlc *PersistentVolumeLabelController) Run(threadiness int, stopCh <-chan struct{}) {
+	defer utilruntime.HandleCrash()
+	defer pvlc.queue.ShutDown()
+
+	glog.Infof("Starting PersistentVolumeLabelController")
+	defer glog.Infof("Shutting down PersistentVolumeLabelController")
+
+	go pvlc.pvlController.Run(stopCh)
+
+	if !controller.WaitForCacheSync("persistent volume label", stopCh, pvlc.pvlController.HasSynced) {
+		return
+	}
+
+	// start up your worker threads based on threadiness.  Some controllers have multiple kinds of workers
+	for i := 0; i < threadiness; i++ {
+		// runWorker will loop until "something bad" happens.  The .Until will then rekick the worker
+		// after one second
+		go wait.Until(pvlc.runWorker, time.Second, stopCh)
+	}
+
+	// wait until we're told to stop
+	<-stopCh
+}
+
+func (pvlc *PersistentVolumeLabelController) runWorker() {
+	// hot loop until we're told to stop.  processNextWorkItem will automatically wait until there's work
+	// available, so we don't worry about secondary waits
+	for pvlc.processNextWorkItem() {
+	}
+}
+
+// processNextWorkItem deals with one key off the queue.  It returns false when it's time to quit.
+func (pvlc *PersistentVolumeLabelController) processNextWorkItem() bool {
+	// pull the next work item from queue.  It should be a key we use to lookup something in a cache
+	keyObj, quit := pvlc.queue.Get()
+	if quit {
+		return false
+	}
+	// you always have to indicate to the queue that you've completed a piece of work
+	defer pvlc.queue.Done(keyObj)
+
+	key := keyObj.(string)
+	// do your work on the key.  This method will contains your "do stuff" logic
+	err := pvlc.syncHandler(key)
+	if err == nil {
+		// if you had no error, tell the queue to stop tracking history for your key.  This will
+		// reset things like failure counts for per-item rate limiting
+		pvlc.queue.Forget(key)
+		return true
+	}
+
+	// there was a failure so be sure to report it.  This method allows for pluggable error handling
+	// which can be used for things like cluster-monitoring
+	utilruntime.HandleError(fmt.Errorf("%v failed with : %v", key, err))
+
+	// since we failed, we should requeue the item to work on later.  This method will add a backoff
+	// to avoid hotlooping on particular items (they're probably still not going to work right away)
+	// and overall controller protection (everything I've done is broken, this controller needs to
+	// calm down or it can starve other useful work) cases.
+	pvlc.queue.AddRateLimited(key)
+
+	return true
+}
+
+// AddLabels adds appropriate labels to persistent volumes and sets the
+// volume as available if successful.
+func (pvlc *PersistentVolumeLabelController) addLabels(key string) error {
+	_, name, err := cache.SplitMetaNamespaceKey(key)
+	if err != nil {
+		return fmt.Errorf("error getting name of volume %q to get volume from informer: %v", key, err)
+	}
+	volume, err := pvlc.volumeLister.Get(name)
+	if errors.IsNotFound(err) {
+		return nil
+	} else if err != nil {
+		return fmt.Errorf("error getting volume %s from informer: %v", name, err)
+	}
+
+	return pvlc.addLabelsToVolume(volume)
+}
+
+func (pvlc *PersistentVolumeLabelController) addLabelsToVolume(vol *v1.PersistentVolume) error {
+	var volumeLabels map[string]string
+
+	// Only add labels if in the list of initializers
+	if needsInitialization(vol.Initializers, initializerName) {
+		if vol.Spec.AWSElasticBlockStore != nil {
+			labels, err := pvlc.findAWSEBSLabels(vol)
+			if err != nil {
+				return fmt.Errorf("error querying AWS EBS volume %s: %v", vol.Spec.AWSElasticBlockStore.VolumeID, err)
+			}
+			volumeLabels = labels
+		}
+		if vol.Spec.GCEPersistentDisk != nil {
+			labels, err := pvlc.findGCEPDLabels(vol)
+			if err != nil {
+				return fmt.Errorf("error querying GCE PD volume %s: %v", vol.Spec.GCEPersistentDisk.PDName, err)
+			}
+			volumeLabels = labels
+		}
+		return pvlc.updateVolume(vol, volumeLabels)
+	}
+
+	return nil
+}
+
+func (pvlc *PersistentVolumeLabelController) findAWSEBSLabels(volume *v1.PersistentVolume) (map[string]string, error) {
+	// Ignore any volumes that are being provisioned
+	if volume.Spec.AWSElasticBlockStore.VolumeID == vol.ProvisionedVolumeName {
+		return nil, nil
+	}
+	ebsVolumes, err := pvlc.getEBSVolumes()
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO: GetVolumeLabels is actually a method on the Volumes interface
+	// If that gets standardized we can refactor to reduce code duplication
+	spec := aws.KubernetesVolumeID(volume.Spec.AWSElasticBlockStore.VolumeID)
+	labels, err := ebsVolumes.GetVolumeLabels(spec)
+	if err != nil {
+		return nil, err
+	}
+
+	return labels, nil
+}
+
+// getEBSVolumes returns the AWS Volumes interface for ebs
+func (pvlc *PersistentVolumeLabelController) getEBSVolumes() (aws.Volumes, error) {
+	pvlc.mutex.Lock()
+	defer pvlc.mutex.Unlock()
+
+	if pvlc.ebsVolumes == nil {
+		awsCloudProvider := pvlc.cloud.(*aws.Cloud)
+		awsCloudProvider, ok := pvlc.cloud.(*aws.Cloud)
+		if !ok {
+			// GetCloudProvider has gone very wrong
+			return nil, fmt.Errorf("error retrieving AWS cloud provider")
+		}
+		pvlc.ebsVolumes = awsCloudProvider
+	}
+	return pvlc.ebsVolumes, nil
+}
+
+func (pvlc *PersistentVolumeLabelController) findGCEPDLabels(volume *v1.PersistentVolume) (map[string]string, error) {
+	// Ignore any volumes that are being provisioned
+	if volume.Spec.GCEPersistentDisk.PDName == vol.ProvisionedVolumeName {
+		return nil, nil
+	}
+
+	provider, err := pvlc.getGCECloudProvider()
+	if err != nil {
+		return nil, err
+	}
+
+	// If the zone is already labeled, honor the hint
+	zone := volume.Labels[kubeletapis.LabelZoneFailureDomain]
+
+	labels, err := provider.GetAutoLabelsForPD(volume.Spec.GCEPersistentDisk.PDName, zone)
+	if err != nil {
+		return nil, err
+	}
+
+	return labels, nil
+}
+
+// getGCECloudProvider returns the GCE cloud provider, for use for querying volume labels
+func (pvlc *PersistentVolumeLabelController) getGCECloudProvider() (*gce.GCECloud, error) {
+	pvlc.mutex.Lock()
+	defer pvlc.mutex.Unlock()
+
+	if pvlc.gceCloudProvider == nil {
+		gceCloudProvider, ok := pvlc.cloud.(*gce.GCECloud)
+		if !ok {
+			// GetCloudProvider has gone very wrong
+			return nil, fmt.Errorf("error retrieving GCE cloud provider")
+		}
+		pvlc.gceCloudProvider = gceCloudProvider
+	}
+	return pvlc.gceCloudProvider, nil
+}
+
+func (pvlc *PersistentVolumeLabelController) createPatch(vol *v1.PersistentVolume, volLabels map[string]string) ([]byte, error) {
+	volName := vol.Name
+	newVolume := vol.DeepCopyObject().(*v1.PersistentVolume)
+	if newVolume.Labels == nil {
+		newVolume.Labels = make(map[string]string)
+	}
+	for k, v := range volLabels {
+		newVolume.Labels[k] = v
+	}
+	newVolume.Initializers = removeInitializer(newVolume.Initializers, initializerName)
+	glog.V(4).Infof("removed initializer on PersistentVolume %s", newVolume.Name)
+
+	oldData, err := json.Marshal(vol)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal old persistentvolume %#v for persistentvolume %q: %v", vol, volName, err)
+	}
+
+	newData, err := json.Marshal(newVolume)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal new persistentvolume %#v for persistentvolume %q: %v", newVolume, volName, err)
+	}
+
+	patch, err := strategicpatch.CreateTwoWayMergePatch(oldData, newData, v1.PersistentVolume{})
+	if err != nil {
+		return nil, fmt.Errorf("failed to create patch for persistentvolume %q: %v", volName, err)
+	}
+	return patch, nil
+}
+
+func (pvlc *PersistentVolumeLabelController) updateVolume(vol *v1.PersistentVolume, volLabels map[string]string) error {
+	volName := vol.Name
+	glog.V(4).Infof("updating PersistentVolume %s", volName)
+	patchBytes, err := pvlc.createPatch(vol, volLabels)
+	if err != nil {
+		return err
+	}
+
+	_, err = pvlc.kubeClient.Core().PersistentVolumes().Patch(string(volName), types.StrategicMergePatchType, patchBytes)
+	if err != nil {
+		return fmt.Errorf("failed to update PersistentVolume %s: %v", volName, err)
+	}
+	glog.V(4).Infof("updated PersistentVolume %s", volName)
+
+	return err
+}
+
+func removeInitializer(initializers *metav1.Initializers, name string) *metav1.Initializers {
+	if initializers == nil {
+		return nil
+	}
+
+	var updated []metav1.Initializer
+	for _, pending := range initializers.Pending {
+		if pending.Name != name {
+			updated = append(updated, pending)
+		}
+	}
+	if len(updated) == len(initializers.Pending) {
+		return initializers
+	}
+	if len(updated) == 0 {
+		return nil
+	}
+
+	return &metav1.Initializers{Pending: updated}
+}
+
+func needsInitialization(initializers *metav1.Initializers, name string) bool {
+	hasInitializer := false
+
+	if initializers != nil {
+		for _, pending := range initializers.Pending {
+			if pending.Name == name {
+				hasInitializer = true
+				break
+			}
+		}
+	}
+	return hasInitializer
+}