Snapshot

We can create a snapshot of a volume that can be used further for creating a clone and for taking a backup. To create a snapshot, we have to first create a SnapshotClass just like a storage class where you can provide deletionPolicy as Retain or Delete.

$ cat snapshotclass.yaml

kind: VolumeSnapshotClass

apiVersion: snapshot.storage.k8s.io/v1

metadata:

name: zfspv-snapclass

annotations:

snapshot.storage.kubernetes.io/is-default-class: "true"

driver: zfs.csi.openebs.io

deletionPolicy: Delete

Apply the snapshotclass YAML:

$ kubectl apply -f snapshotclass.yaml

volumesnapshotclass.snapshot.storage.k8s.io/zfspv-snapclass created

Find a PVC for which snapshot has to be created.

$ kubectl get pvc

NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE

csi-zfspv Bound pvc-73402f6e-d054-4ec2-95a4-eb8452724afb 4Gi RWO openebs-zfspv 2m35s

Create the snapshot using the created SnapshotClass for the selected PVC.

$ cat snapshot.yaml

apiVersion: snapshot.storage.k8s.io/v1

kind: VolumeSnapshot

metadata:

name: zfspv-snap

spec:

volumeSnapshotClassName: zfspv-snapclass

source:

persistentVolumeClaimName: csi-zfspv

Apply the snapshot.yaml.

$ kubectl apply -f snapshot.yaml

volumesnapshot.snapshot.storage.k8s.io/zfspv-snap created

note

Create the snapshot in the same namespace where the PVC is created. Check the created snapshot resource, make sure readyToUsefield is true, before using this snapshot for any purpose.

$ kubectl get volumesnapshot.snapshot

NAME AGE

zfspv-snap 2m8s

$ kubectl get volumesnapshot.snapshot zfspv-snap -o yaml

apiVersion: snapshot.storage.k8s.io/v1

kind: VolumeSnapshot

metadata:

annotations:

kubectl.kubernetes.io/last-applied-configuration: |

{"apiVersion":"snapshot.storage.k8s.io/v1","kind":

"VolumeSnapshot","metadata":{"annotations":{},"name":

"zfspv-snap","namespace":"default"},"spec":{"source":{"persistentVolumeClaimName":"csi-zfspv"},"volumeSnapshotClassName":"zfspv-snapclass"}}

creationTimestamp: "2020-02-25T08:25:51Z"

finalizers:

- snapshot.storage.kubernetes.io/volumesnapshot-as-source-protection

- snapshot.storage.kubernetes.io/volumesnapshot-bound-protection

generation: 1

name: zfspv-snap

namespace: default

resourceVersion: "447494"

selfLink: /apis/snapshot.storage.k8s.io/v1/namespaces/default/volumesnapshots/zfspv-snap

uid: 3cbd5e59-4c6f-4bd6-95ba-7f72c9f12fcd

spec:

source:

persistentVolumeClaimName: csi-zfspv

volumeSnapshotClassName: zfspv-snapclass

status:

boundVolumeSnapshotContentName: snapcontent-3cbd5e59-4c6f-4bd6-95ba-7f72c9f12fcd

creationTime: "2020-02-25T08:25:51Z"

readyToUse: true

restoreSize: "0"

Check the OpenEBS resource for the created snapshot. The status should be "Ready".

$ kubectl get zfssnap -n openebs

NAME AGE

snapshot-3cbd5e59-4c6f-4bd6-95ba-7f72c9f12fcd 3m32s

$ kubectl get zfssnap snapshot-3cbd5e59-4c6f-4bd6-95ba-7f72c9f12fcd -n openebs -oyaml

apiVersion: openebs.io/v1alpha1

kind: ZFSSnapshot

metadata:

creationTimestamp: "2020-02-25T08:25:51Z"

finalizers:

- zfs.openebs.io/finalizer

generation: 2

labels:

kubernetes.io/nodename: e2e1-node2

openebs.io/persistent-volume: pvc-73402f6e-d054-4ec2-95a4-eb8452724afb

name: snapshot-3cbd5e59-4c6f-4bd6-95ba-7f72c9f12fcd

namespace: openebs

resourceVersion: "447328"

selfLink: /apis/openebs.io/v1alpha1/namespaces/openebs/zfssnapshots/snapshot-3cbd5e59-4c6f-4bd6-95ba-7f72c9f12fcd

uid: 6142492c-3785-498f-aa4a-569ec6c0e2b8

spec:

capacity: "4294967296"

fsType: zfs

ownerNodeID: e2e1-node2

poolName: test-pool

volumeType: DATASET

status:

state: Ready

We can go to the node and confirm that snapshot has been created:

# zfs list -t all

NAME USED AVAIL REFER MOUNTPOINT

test-pool 818K 9.63G 24K /test-pool

test-pool/pvc-73402f6e-d054-4ec2-95a4-eb8452724afb 24K 4.00G 24K /var/lib/kubelet/pods/3862895a-8a67-446e-80f7-f3c18881e391/volumes/kubernetes.io~csi/pvc-73402f6e-d054-4ec2-95a4-eb8452724afb/mount

test-pool/pvc-73402f6e-d054-4ec2-95a4-eb8452724afb@snapshot-3cbd5e59-4c6f-4bd6-95ba-7f72c9f12fcd 0B - 24K -