Creating a PVC Change

1: Preparing a PVC Change File
2: Creating a PVC Change Resource

Prerequisites

The storage backends associated with the PVC to be changed are HyperMetro storage backends. If they are not HyperMetro storage backends, configure them by following the instructions in Manually Updating a Storage Backend.

1 - Preparing a PVC Change File

PVC Change File Description

The sample template of the PVC change file is /examples/volumemodifyclaim.yaml. The following table lists the configuration items.

Table 1 Parameter description

Parameter	Description	Mandatory	Default Value	Remarks
apiVersion	API group, which is of the string type.	Yes	xuanwu.huawei.io/v1	The value is fixed at xuanwu.huawei.io/v1.
kind	Resource type, which is of the string type.	Yes	VolumeModifyClaim	The value is fixed at VolumeModifyClaim.
metadata.name	Name of a cluster resource object, which is of the string type.	Yes	-	The name must comply with the naming rules of a DNS subdomain name. The value can contain a maximum of 63 characters, including digits, lowercase letters, hyphens (-), and periods (.). It must start and end with a lowercase letter or digit.
spec.source.kind	Data source type, which is of the string type.	Yes	StorageClass	This parameter can only be set to StorageClass.
spec.source.name	Data source name, which is of the string type.	Yes	-	Only a StorageClass name can be configured.
spec.parameters.hyperMetro	Whether to change a common volume to a HyperMetro volume. Currently, the value can only be "true".	Yes	-	Only common storage volumes at the primary site can be changed to HyperMetro storage volumes.
spec.parameters.metroPairSyncSpeed	Data synchronization speed of a HyperMetro pair. The value ranges from 1 to 4. The value can be: 1: low 2: medium 3: high 4: highest	No	-	This parameter is available only when spec.parameters.hyperMetro is set to "true". Note: If this parameter is not configured, the storage speed of the HyperMetro pair is determined by the storage device. The highest synchronization speed may increase the host latency.

The spec.source.kind and spec.source.name parameters are used to specify the volume change scope. For example, if they are set to a StorageClass and the corresponding name respectively, all PVCs in the Bound state provisioned using the target StorageClass will be changed.
After all associated PVCs are changed, Huawei CSI will replace the original StorageClass and add the spec.parameters parameter of the VolumeModifyClaim so that the PVCs meet the StorageClass definition.

For details about the configuration in typical scenarios, see the following example:

Changing a Common Volume to a HyperMetro Volume

The following is an example of changing a common volume to a HyperMetro volume:

apiVersion: xuanwu.huawei.io/v1
kind: VolumeModifyClaim
metadata:
  name: myvmc
spec:
  source:
    kind: StorageClass
    name: mysc
  parameters:
    hyperMetro: "true"

2 - Creating a PVC Change Resource

This section describes how to create a PVC change resource based on a configured PVC change file.

Only the HyperMetro active-active (AA) mode is supported.
When a common volume is changed to a HyperMetro volume, only the storage volume at the primary site can be changed.
Do not use Huawei CSI to manage a PVC during PVC change resource creation.
Multiple VolumeModifyClaim resources cannot be created for the same PVC. If the target PVC needs to be changed for multiple times, perform the changes one by one.

Procedure

Use a remote access tool, such as PuTTY, to log in to any master node in the Kubernetes cluster through the management IP address.
Run the following command to create a PVC change.
```
kubectl create -f volumemodifyclaim.yaml 
```
Query the creation result by following the instructions in Querying a PVC Change.