Configuring a VolumeSnapshot

1: Dynamically Provisioning a VolumeSnapshot
2: Pre-provisioning a VolumeSnapshot

VolumeSnapshot configurations can be classified into dynamically provisioned VolumeSnapshots and pre-provisioned VolumeSnapshots.

A dynamically provisioned VolumeSnapshot is created by using VolumeSnapshot resources to dynamically obtain and create a snapshot from PVCs, without using existing snapshots.
A pre-provisioned VolumeSnapshot requires the administrator to create the required snapshot on the storage device in advance and use the existing snapshot by creating a VolumeSnapshotContent. In addition, you can specify the associated VolumeSnapshotContent when creating a VolumeSnapshot.

1 - Dynamically Provisioning a VolumeSnapshot

This section describes how to dynamically provision a VolumeSnapshot using Huawei CSI.

Prerequisites

The source PVC exists, and the backend where the PVC resides supports VolumeSnapshot creation.

Creating a Snapshot for a Volume

The following is an example of the VolumeSnapshot configuration file:

apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshot
metadata:
  name: mysnapshot
spec:
  volumeSnapshotClassName: mysnapclass
  source:
    persistentVolumeClaimName: mypvc

You can modify the parameters according to Table 1 .

Table 1 VolumeSnapshot parameters

Parameter	Description	Remarks
metadata.name	User-defined name of a VolumeSnapshot object.	Take Kubernetes v1.22.1 as an example. The value can contain digits, lowercase letters, hyphens (-), and periods (.), and must start and end with a letter or digit.
spec.volumeSnapshotClassName	Name of the VolumeSnapshotClass object.	--
spec.source.persistentVolumeClaimName	Name of the source PVC object.	Name of the source PVC of the snapshot

Run the following command to create a VolumeSnapshot using the created VolumeSnapshot configuration file.
```
kubectl create -f mysnapshot.yaml
```

Run the following command to view the information about the created VolumeSnapshot.

kubectl get volumesnapshot

The following is an example of the command output.

NAME         READYTOUSE   SOURCEPVC   SOURCESNAPSHOTCONTENT   RESTORESIZE   SNAPSHOTCLASS   SNAPSHOTCONTENT                                    CREATIONTIME   AGE
mysnapshot   true         mypvc                               100Gi         mysnapclass     snapcontent-1009af0a-24c2-4435-861c-516224503f2d   <invalid>      78s

2 - Pre-provisioning a VolumeSnapshot

This section describes how to pre-provision a VolumeSnapshot using Huawei CSI.

Prerequisites

A source VolumeSnapshot has been created on the Huawei storage device, and the created snapshot name can be obtained.

Creating a VolumeSnapshot Entity

The following is an example of the VolumeSnapshotContent file:

apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshotContent
metadata:
  name: mysnapshotcontent
spec:
  deletionPolicy: Retain
  driver: csi.huawei.com
  volumeSnapshotRef:
    apiVersion: snapshot.storage.k8s.io/v1
    kind: VolumeSnapshot
    name: mysnapshot
    namespace: default
  source:
    snapshotHandle: mybackend.1.snapshot_001
  volumeSnapshotClassName: "mysnapclass"

You can modify the parameters according to Table 1 .

Table 1 VolumeSnapshotContent parameters

Parameter	Description	Remarks
metadata.name	User-defined name of a VolumeSnapshotContent object.	Take Kubernetes v1.22.1 as an example. The value can contain digits, lowercase letters, hyphens (-), and periods (.), and must start and end with a letter or digit.
spec.deletionPolicy	Deletion policy. The following types are supported: Delete: Resources are automatically reclaimed. Retain: Resources are manually reclaimed.	Delete: When a VolumeSnapshotContent is deleted, the snapshot resources on the storage are also deleted. Retain: When a VolumeSnapshotContent is deleted, the snapshot resources on the storage are not deleted.
spec.driver	Driver name.	Set this parameter to the driver name set during Huawei CSI installation. The value is the same as that of driverName in the values.yaml file.
spec.volumeSnapshotRef	Information about the target VolumeSnapshot to be bound, including the VolumeSnapshot name and namespace.	--
spec.source.snapshotHandle	Unique identifier of a storage snapshot resource. This parameter is mandatory. The format is <backend-name>.<parent-id>.<snapshot-name>.	The value of this parameter consists of the following parts: <backend-name>: indicates the backend name corresponding to the snapshot resource. You can run the oceanctl get backend command to obtain the configured backend information. <parent-id>: indicates the ID of the parent resource object of the snapshot resource on the storage device. You can view the ID on DeviceManager. <snapshot-name>: indicates the name of the snapshot resource on the storage device. You can view the name on DeviceManager. NOTICE: The <snapshot-name> parameter can contain only digits, letters, and underscores (_).
spec.volumeSnapshotClassName	Name of the VolumeSnapshotClass object.	--

Run the following command to create a VolumeSnapshotContent using the created VolumeSnapshotContent configuration file.
```
kubectl create -f mysnapshotcontent.yaml
```

Run the following command to view the information about the created VolumeSnapshot.

kubectl get volumesnapshotcontent

The following is an example of the command output.

NAME               READYTOUSE   RESTORESIZE   DELETIONPOLICY   DRIVER           VOLUMESNAPSHOTCLASS   VOLUMESNAPSHOT   VOLUMESNAPSHOTNAMESPACE   AGE
mysnapshotcontent  true         0             Retain           csi.huawei.com   mysnapclass           mysnapshot       default                   4s

Creating a Snapshot for a Volume

After a VolumeSnapshotContent is created in provisioned mode, you can create a VolumeSnapshot based on the VolumeSnapshotContent. The following is an example of the VolumeSnapshot configuration file:

apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshot
metadata:
  name: mysnapshot
  namespace: default
spec:
  volumeSnapshotClassName: mysnapclass
  source:
    volumeSnapshotContentName: mysnapshotcontent

You can modify the parameters according to Table 2 .

Table 2 VolumeSnapshot parameters

Parameter	Description	Remarks
metadata.name	User-defined name of a VolumeSnapshot object.	Take Kubernetes v1.22.1 as an example. The value can contain digits, lowercase letters, hyphens (-), and periods (.), and must start and end with a letter or digit. The value must be the same as the name of the VolumeSnapshot specified by VolumeSnapshotContent.
metadata.namespace	Namespace to which the VolumeSnapshot belongs.	The value must be the same as the namespace of the VolumeSnapshot specified by VolumeSnapshotContent.
spec.volumeSnapshotClassName	Name of the VolumeSnapshotClass object.	--
spec.source.volumeSnapshotContentName	Name of the source VolumeSnapshotContent object.	Name of the source VolumeSnapshotContent of the snapshot.

Run the following command to create a VolumeSnapshot using the created VolumeSnapshot configuration file.
```
kubectl create -f mysnapshot.yaml
```

Run the following command to view the information about the created VolumeSnapshot.

kubectl get volumesnapshot

The following is an example of the command output.

NAME         READYTOUSE  SOURCEPVC  SOURCESNAPSHOTCONTENT   RESTORESIZE   SNAPSHOTCLASS   SNAPSHOTCONTENT     CREATIONTIME   AGE
mysnapshot   true                   mysnapshotcontent       0             mysnapclass     mysnapshotcontent   2m39s          8s