feat(zfspv): adding backup and restore support (#162)

This commit adds support for Backup and Restore controller, which will be watching for
the events. The velero plugin will create a Backup CR to create a backup
with the remote location information, the controller will send the data
to that remote location.

In the same way, the velero plugin will create a Restore CR to restore the
volume from the the remote location and the restore controller will restore
the data.

Steps to use velero plugin for ZFS-LocalPV are :

1. install velero

2. add openebs plugin

velero plugin add openebs/velero-plugin:latest

3. Create the volumesnapshot location :

for full backup :-

```yaml
apiVersion: velero.io/v1
kind: VolumeSnapshotLocation
metadata:
  name: default
  namespace: velero
spec:
  provider: openebs.io/zfspv-blockstore
  config:
    bucket: velero
    prefix: zfs
    namespace: openebs
    provider: aws
    region: minio
    s3ForcePathStyle: "true"
    s3Url: http://minio.velero.svc:9000
```

for incremental backup :-

```yaml
apiVersion: velero.io/v1
kind: VolumeSnapshotLocation
metadata:
  name: default
  namespace: velero
spec:
  provider: openebs.io/zfspv-blockstore
  config:
    bucket: velero
    prefix: zfs
    backup: incremental
    namespace: openebs
    provider: aws
    region: minio
    s3ForcePathStyle: "true"
    s3Url: http://minio.velero.svc:9000
```

4. Create backup

velero backup create my-backup --snapshot-volumes --include-namespaces=velero-ns --volume-snapshot-locations=aws-cloud-default --storage-location=default

5. Create Schedule

velero create schedule newschedule  --schedule="*/1 * * * *" --snapshot-volumes --include-namespaces=velero-ns --volume-snapshot-locations=aws-local-default --storage-location=default

6. Restore from backup

velero restore create --from-backup my-backup --restore-volumes=true --namespace-mappings velero-ns:ns1



Signed-off-by: Pawan <pawan@mayadata.io>

pkg/mgmt/backup/builder.go

@@ -0,0 +1,136 @@
+/*
+Copyright 2020 The OpenEBS 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 backup
+
+import (
+	"k8s.io/klog"
+
+	clientset "github.com/openebs/zfs-localpv/pkg/generated/clientset/internalclientset"
+	openebsScheme "github.com/openebs/zfs-localpv/pkg/generated/clientset/internalclientset/scheme"
+	informers "github.com/openebs/zfs-localpv/pkg/generated/informer/externalversions"
+	listers "github.com/openebs/zfs-localpv/pkg/generated/lister/zfs/v1"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/kubernetes/scheme"
+	typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/client-go/tools/record"
+	"k8s.io/client-go/util/workqueue"
+)
+
+const controllerAgentName = "zfsbackup-controller"
+
+// BkpController is the controller implementation for Bkp resources
+type BkpController struct {
+	// kubeclientset is a standard kubernetes clientset
+	kubeclientset kubernetes.Interface
+
+	// clientset is a openebs custom resource package generated for custom API group.
+	clientset clientset.Interface
+
+	bkpLister listers.ZFSBackupLister
+
+	// backupSynced is used for caches sync to get populated
+	bkpSynced cache.InformerSynced
+
+	// workqueue is a rate limited work queue. This is used to queue work to be
+	// processed instead of performing it as soon as a change happens. This
+	// means we can ensure we only process a fixed amount of resources at a
+	// time, and makes it easy to ensure we are never processing the same item
+	// simultaneously in two different workers.
+	workqueue workqueue.RateLimitingInterface
+
+	// recorder is an event recorder for recording Event resources to the
+	// Kubernetes API.
+	recorder record.EventRecorder
+}
+
+// BkpControllerBuilder is the builder object for controller.
+type BkpControllerBuilder struct {
+	BkpController *BkpController
+}
+
+// NewBkpControllerBuilder returns an empty instance of controller builder.
+func NewBkpControllerBuilder() *BkpControllerBuilder {
+	return &BkpControllerBuilder{
+		BkpController: &BkpController{},
+	}
+}
+
+// withKubeClient fills kube client to controller object.
+func (cb *BkpControllerBuilder) withKubeClient(ks kubernetes.Interface) *BkpControllerBuilder {
+	cb.BkpController.kubeclientset = ks
+	return cb
+}
+
+// withOpenEBSClient fills openebs client to controller object.
+func (cb *BkpControllerBuilder) withOpenEBSClient(cs clientset.Interface) *BkpControllerBuilder {
+	cb.BkpController.clientset = cs
+	return cb
+}
+
+// withBkpLister fills bkp lister to controller object.
+func (cb *BkpControllerBuilder) withBkpLister(sl informers.SharedInformerFactory) *BkpControllerBuilder {
+	bkpInformer := sl.Zfs().V1().ZFSBackups()
+	cb.BkpController.bkpLister = bkpInformer.Lister()
+	return cb
+}
+
+// withBkpSynced adds object sync information in cache to controller object.
+func (cb *BkpControllerBuilder) withBkpSynced(sl informers.SharedInformerFactory) *BkpControllerBuilder {
+	bkpInformer := sl.Zfs().V1().ZFSBackups()
+	cb.BkpController.bkpSynced = bkpInformer.Informer().HasSynced
+	return cb
+}
+
+// withWorkqueue adds workqueue to controller object.
+func (cb *BkpControllerBuilder) withWorkqueueRateLimiting() *BkpControllerBuilder {
+	cb.BkpController.workqueue = workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "Bkp")
+	return cb
+}
+
+// withRecorder adds recorder to controller object.
+func (cb *BkpControllerBuilder) withRecorder(ks kubernetes.Interface) *BkpControllerBuilder {
+	klog.Infof("Creating event broadcaster")
+	eventBroadcaster := record.NewBroadcaster()
+	eventBroadcaster.StartLogging(klog.Infof)
+	eventBroadcaster.StartRecordingToSink(&typedcorev1.EventSinkImpl{Interface: ks.CoreV1().Events("")})
+	recorder := eventBroadcaster.NewRecorder(scheme.Scheme, corev1.EventSource{Component: controllerAgentName})
+	cb.BkpController.recorder = recorder
+	return cb
+}
+
+// withEventHandler adds event handlers controller object.
+func (cb *BkpControllerBuilder) withEventHandler(cvcInformerFactory informers.SharedInformerFactory) *BkpControllerBuilder {
+	cvcInformer := cvcInformerFactory.Zfs().V1().ZFSBackups()
+	// Set up an event handler for when Bkp resources change
+	cvcInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
+		AddFunc:    cb.BkpController.addBkp,
+		UpdateFunc: cb.BkpController.updateBkp,
+		DeleteFunc: cb.BkpController.deleteBkp,
+	})
+	return cb
+}
+
+// Build returns a controller instance.
+func (cb *BkpControllerBuilder) Build() (*BkpController, error) {
+	err := openebsScheme.AddToScheme(scheme.Scheme)
+	if err != nil {
+		return nil, err
+	}
+	return cb.BkpController, nil
+}