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/generated/informer/externalversions/zfs/v1/zfsrestore.go

@@ -0,0 +1,89 @@
+/*
+Copyright 2019 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.
+*/
+
+// Code generated by informer-gen. DO NOT EDIT.
+
+package v1
+
+import (
+	time "time"
+
+	zfsv1 "github.com/openebs/zfs-localpv/pkg/apis/openebs.io/zfs/v1"
+	internalclientset "github.com/openebs/zfs-localpv/pkg/generated/clientset/internalclientset"
+	internalinterfaces "github.com/openebs/zfs-localpv/pkg/generated/informer/externalversions/internalinterfaces"
+	v1 "github.com/openebs/zfs-localpv/pkg/generated/lister/zfs/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	runtime "k8s.io/apimachinery/pkg/runtime"
+	watch "k8s.io/apimachinery/pkg/watch"
+	cache "k8s.io/client-go/tools/cache"
+)
+
+// ZFSRestoreInformer provides access to a shared informer and lister for
+// ZFSRestores.
+type ZFSRestoreInformer interface {
+	Informer() cache.SharedIndexInformer
+	Lister() v1.ZFSRestoreLister
+}
+
+type zFSRestoreInformer struct {
+	factory          internalinterfaces.SharedInformerFactory
+	tweakListOptions internalinterfaces.TweakListOptionsFunc
+	namespace        string
+}
+
+// NewZFSRestoreInformer constructs a new informer for ZFSRestore type.
+// Always prefer using an informer factory to get a shared informer instead of getting an independent
+// one. This reduces memory footprint and number of connections to the server.
+func NewZFSRestoreInformer(client internalclientset.Interface, namespace string, resyncPeriod time.Duration, indexers cache.Indexers) cache.SharedIndexInformer {
+	return NewFilteredZFSRestoreInformer(client, namespace, resyncPeriod, indexers, nil)
+}
+
+// NewFilteredZFSRestoreInformer constructs a new informer for ZFSRestore type.
+// Always prefer using an informer factory to get a shared informer instead of getting an independent
+// one. This reduces memory footprint and number of connections to the server.
+func NewFilteredZFSRestoreInformer(client internalclientset.Interface, namespace string, resyncPeriod time.Duration, indexers cache.Indexers, tweakListOptions internalinterfaces.TweakListOptionsFunc) cache.SharedIndexInformer {
+	return cache.NewSharedIndexInformer(
+		&cache.ListWatch{
+			ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
+				if tweakListOptions != nil {
+					tweakListOptions(&options)
+				}
+				return client.ZfsV1().ZFSRestores(namespace).List(options)
+			},
+			WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
+				if tweakListOptions != nil {
+					tweakListOptions(&options)
+				}
+				return client.ZfsV1().ZFSRestores(namespace).Watch(options)
+			},
+		},
+		&zfsv1.ZFSRestore{},
+		resyncPeriod,
+		indexers,
+	)
+}
+
+func (f *zFSRestoreInformer) defaultInformer(client internalclientset.Interface, resyncPeriod time.Duration) cache.SharedIndexInformer {
+	return NewFilteredZFSRestoreInformer(client, f.namespace, resyncPeriod, cache.Indexers{cache.NamespaceIndex: cache.MetaNamespaceIndexFunc}, f.tweakListOptions)
+}
+
+func (f *zFSRestoreInformer) Informer() cache.SharedIndexInformer {
+	return f.factory.InformerFor(&zfsv1.ZFSRestore{}, f.defaultInformer)
+}
+
+func (f *zFSRestoreInformer) Lister() v1.ZFSRestoreLister {
+	return v1.NewZFSRestoreLister(f.Informer().GetIndexer())
+}