Volume Restore from Snapshot

Volume restore from an existing snapshot will create an exact replica of a storage volume captured at a specific point in time. They serve as an essential tool for data protection, recovery, and efficient management in Kubernetes environments. This article provides a step-by-step guide on how to create a volume restore.

info

A volume snapshot transcends into taking snapshots on each of the volume's replicas for consistency. For instance, a snapshot on a source volume with three replicas (repl=3) results in snapshot-ting all three replicas of the source volume. Similarly, the replica count of the new volume must be less than or equal to the available replica snapshot count of the corresponding source volume when a restore is initiated, or a new volume is provisioned by specifying the source volume's snapshot as the source.

• Do the following command to find the number of available replicas of a volume:

Command

kubectl mayastor get volume-replica-topology ec4e66fd-3b33-4439-b504-d49aba53da26        

Output

ID                                    NODE         POOL    STATUS  CAPACITY  ALLOCATED  SNAPSHOTS  CHILD-STATUS  REASON  REBUILD 

5de77b1e-56cf-47c9-8fca-e6a5f316684b  io-engine-1  pool-1  Online  12MiB     0 B        12MiB      <none>        <none>  <none> 

78fa3173-175b-4339-9250-47ddccb79201  io-engine-2  pool-2  Online  12MiB     0 B        12MiB      <none>        <none>  <none> 

7b4e678a-e607-40e3-afce-b3b7e99e511a  io-engine-3  pool-3  Online  12MiB     8MiB       0 B        <none>        <none>  <none> 

• Do the following command to check the replica snapshot information for volume snapshots:

Command

kubectl mayastor get volume-snapshot-topology --volume ec4e66fd-3b33-4439-b504-d49aba53da26

Output

SNAPSHOT-ID                           ID                                    POOL    SNAPSHOT_STATUS  SIZE      ALLOCATED_SIZE  SOURCE 

25823425-41fa-434a-9efd-a356b70b5d7c  cb8d200b-c7d8-4ccd-bb62-78f903e444e4  pool-2  Online           12582912  12582912        78fa3173-175b-4339-9250-47ddccb79201 

└─                                    b09f4097-85fa-41c9-a2f8-56198641258d  pool-1  Online           12582912  12582912        5de77b1e-56cf-47c9-8fca-e6a5f316684b 

25823425-41fa-434a-9efd-a356b70b5d7d  1b69b3ca-8f08-4889-8f90-1a428e088c46  pool-2  Online           12582912  0               78fa3173-175b-4339-9250-47ddccb79201 

├─                                    1837b17a-9773-437c-b926-dda3272e3c60  pool-1  Online           12582912  0               5de77b1e-56cf-47c9-8fca-e6a5f316684b 

└─                                    1f8827e7-9674-4879-8f29-b15752aef902  pool-3  Online           12582912  8388608         7b4e678a-e607-40e3-afce-b3b7e99e511a 

Prerequisites

Step 1: Create a StorageClass

To begin, you will need to create a StorageClass that defines the properties of the snapshot to be restored. Refer to StorageClass Parameters for more details. Use the following command to create the StorageClass:

info

Currently, restores are thin-provisioned volumes created from a snapshot, Therefore, the storage class for the restored volume must also specify thin: "true".

Command

cat <<EOF | kubectl create -f -

apiVersion: storage.k8s.io/v1

kind: StorageClass

metadata:

name: mayastor-3-restore

parameters:

protocol: nvmf

repl: "3"

thin: "true"

provisioner: io.openebs.csi-mayastor

EOF

YAML

apiVersion: storage.k8s.io/v1

kind: StorageClass

metadata:

name: mayastor-3-restore

parameters:

protocol: nvmf

repl: "3"

thin: "true"

provisioner: io.openebs.csi-mayastor

note

The name of the StorageClass, which, in the example above, is mayastor-3-restore.

Step 2: Create a Snapshot

You need to create a volume snapshot before proceeding with the restore. Follow the steps outlined in this guide to create a volume snapshot.

note

The snapshot's name, for example, mayastor-pvc-snap.

Create a Volume Restore of the Existing Snapshot

After creating a snapshot, you can create a PersistentVolumeClaim (PVC) from it to generate the volume restore. Use the following command:

Command

cat <<EOF | kubectl create -f -

apiVersion: v1

kind: PersistentVolumeClaim

metadata:

name: restore-pvc //add a name for your new volume

spec:

storageClassName: mayastor-3-restore //add your storage class name

dataSource:

name: mayastor-pvc-snap //add your volumeSnapshot name

kind: VolumeSnapshot

apiGroup: snapshot.storage.k8s.io

accessModes:

- ReadWriteOnce

resources:

requests:

storage: 10Gi

EOF

YAML

apiVersion: v1

kind: PersistentVolumeClaim

metadata:

name: restore-pvc //add a name for your new volume

spec:

storageClassName: mayastor-3-restore //add your storage class name

dataSource:

name: mayastor-pvc-snap //add your volumeSnapshot name

kind: VolumeSnapshot

apiGroup: snapshot.storage.k8s.io

accessModes:

- ReadWriteOnce

resources:

requests:

storage: 10Gi

By running this command, you create a new PVC named restore-pvc based on the specified snapshot. The restored volume will have the same data and configuration as the original volume had at the time of the snapshot.