ceph-csi/docs/cephfs-snap-clone.md
Jeremy Facchetti b9dd54e238 doc: added precisions about snapshotting and cloning
Signed-off-by: Jeremy Facchetti <facchettos@gmail.com>
2020-09-29 12:48:30 +00:00

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# Create CephFS snapshot and Clone Volume
- [Create CephFS snapshot and Clone Volume](#create-cephfs-snapshot-and-clone-volume)
- [Prerequisite](#prerequisite)
- [Snapshot](#snapshot)
- [Create snapshotclass](#create-snapshotclass)
- [Create snapshot](#create-snapshot)
- [Restore snapshot to a new PVC](#restore-snapshot-to-a-new-pvc)
- [Clone PVC](#clone-pvc)
## Prerequisite
- For snapshot functionality to be supported for your Kubernetes cluster, the
Kubernetes version running in your cluster should be >= v1.17. We also need the
`snapshot controller` deployed in your Kubernetes cluster along with `csi-snapshotter`
sidecar container.
Refer [external-snapshotter](https://github.com/kubernetes-csi/external-snapshotter/)
for more information on these sidecar controllers. There should
be a `volumesnapshotclass` object present in the cluster
for snapshot request to be satisified.
**NOTE: At present, there is a limit of 400 snapshots per cephFS filesystem.
Also PVC cannot be deleted if it's having snapshots. Make sure all the snapshots
on the PVC are deleted before you delete the PVC.**
## Snapshot
### Create snapshotclass
```console
kubectl create -f ../examples/cephfs/snapshotclass.yaml
```
### Create snapshot
The snapshot is created on/for an existing PVC. You should
have a PVC in bound state before creating snapshot from it.
It is recommended to create a volume snapshot or a PVC clone
only when the PVC is not in use.
Please refer pvc creation [doc](https://github.com/ceph/ceph-csi/blob/master/docs/deploy-cephfs.md)
for more information on how to create a PVC.
- Verify if PVC is in Bound state
```console
$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
csi-cephfs-pvc Bound pvc-1ea51547-a88b-4ab0-8b4a-812caeaf025d 1Gi RWX csi-cephfs-sc 20h
```
- Create snapshot of the bound PVC
```console
$ kubectl create -f ../examples/cephfs/snapshot.yaml
volumesnapshot.snapshot.storage.k8s.io/cephfs-pvc-snapshot created
```
- Get details about the snapshot
```console
$ kubectl get volumesnapshot
NAME READYTOUSE SOURCEPVC SOURCESNAPSHOTCONTENT RESTORESIZE SNAPSHOTCLASS SNAPSHOTCONTENT CREATIONTIME AGE
cephfs-pvc-snapshot true csi-cephfs-pvc 1Gi csi-cephfsplugin-snapclass snapcontent-34476204-a14a-4d59-bfbc-2bbba695652c 3s 6s
```
- Get details about the volumesnapshotcontent
```console
$ kubectl get volumesnapshotcontent
NAME READYTOUSE RESTORESIZE DELETIONPOLICY DRIVER VOLUMESNAPSHOTCLASS VOLUMESNAPSHOT AGE
snapcontent-34476204-a14a-4d59-bfbc-2bbba695652c true 1073741824 Delete cephfs.csi.ceph.com csi-cephfsplugin-snapclass cephfs-pvc-snapshot 64s
```
## Restore snapshot to a new PVC
```console
$ kubectl create -f ../examples/cephfs/pvc-restore.yaml
$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
csi-cephfs-pvc Bound pvc-1ea51547-a88b-4ab0-8b4a-812caeaf025d 1Gi RWX csi-cephfs-sc 20h
cephfs-pvc-restore Bound pvc-95308c75-6c93-4928-a551-6b5137192209 1Gi RWX csi-cephfs-sc 11m
```
## Clone PVC
```console
$ kubectl create -f ../examples/cephfs/pvc-clone.yaml
$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
csi-cephfs-pvc Bound pvc-1ea51547-a88b-4ab0-8b4a-812caeaf025d 1Gi RWX csi-cephfs-sc 20h
cephfs-pvc-clone Bound pvc-b575bc35-d521-4c41-b4f9-1d733cd28fdf 1Gi RWX csi-cephfs-sc 39s
cephfs-pvc-restore Bound pvc-95308c75-6c93-4928-a551-6b5137192209 1Gi RWX csi-cephfs-sc 55m
```