PVC Change

• 1: Enabling the PVC Change Feature
• 1.1: Enabling the PVC Change Feature Using Helm
• 1.2: Enabling the PVC Change Feature Manually
• 2: Configuring PVC Changes
• 2.1: Creating a PVC Change
• 2.1.1: Preparing a PVC Change File
• 2.1.2: Creating a PVC Change Resource
• 2.2: Querying a PVC Change
• 2.3: Deleting a PVC Change

1 - Enabling the PVC Change Feature

The PVC change feature is disabled by default during Huawei CSI installation. To use this feature, perform the following steps.

1.1 - Enabling the PVC Change Feature Using Helm

Prerequisites

• You have installed Huawei CSI using Helm.
• Huawei CSI v4.5.0 or later is used.

Procedure

1. Use a remote access tool, such as PuTTY, to log in to any master node in the Kubernetes cluster through the management IP address.

2. Run the following command to check whether the PVC change feature is enabled.

   helm-huawei-csi indicates the Helm chart name specified during installation, and huawei-csi indicates the Helm chart namespace specified during installation. For details about the component package path, see Table 1.

   helm get values helm-huawei-csi -n huawei-csi -a | grep volumeModify -A 1
   

   The following is an example of the command output.

   • If enabled: true is displayed in the command output, the feature is enabled. In this case, skip the following steps.
   • If enabled: false is displayed in the command output, perform the following steps to enable the PVC change feature.

   volumeModify:
     enabled: false
   

3. Go to the /helm/esdk directory and run the following command to configure the volume change CRD.

   # kubectl apply -f ./crds/volume-modify/
   customresourcedefinition.apiextensions.k8s.io/volumemodifyclaims.xuanwu.huawei.io configured
   customresourcedefinition.apiextensions.k8s.io/volumemodifycontents.xuanwu.huawei.io configured
   

   If the command output contains Warning: resource customresourcedefinitions/volumemodifycontents.xuanwu.huawei.io is missing the kubectl.kubernetes.io/last-applied-configuration…, you can ignore it. This message is displayed because the kubectl create command instead of the kubectl apply command is used for installation by Helm.

4. Run the following command to obtain the original service configuration file.

   helm get values helm-huawei-csi -n huawei-csi -a > ./update-values.yaml
   

5. Run the vi update-values.yaml command to open the file obtained in 4 and modify the following configuration. After the modification is complete, press Esc and enter :wq! to save the modification.

   csiExtender:
     volumeModify:    
       enabled: true
   

6. Run the following command to update Huawei CSI services.

   helm upgrade helm-huawei-csi ./ -n huawei-csi  -f ./update-values.yaml
   

7. Run the following command to check whether the services are started.

   kubectl get pod -n huawei-csi
   

   The following is an example of the command output. In the preceding command, huawei-csi indicates the namespace for deploying Huawei CSI.

   NAME                                     READY     STATUS    RESTARTS   AGE
   huawei-csi-controller-6dfcc4b79f-9vjtq   10/10     Running   0          24m
   huawei-csi-node-tqs87                    3/3       Running   0          20m
   

1.2 - Enabling the PVC Change Feature Manually

Prerequisites

Huawei CSI has been manually installed.

Procedure

1. Use a remote access tool, such as PuTTY, to log in to any master node in the Kubernetes cluster through the management IP address.

2. Go to the manual/esdk working directory and run the following command to configure the volume change CRD.

   kubectl apply -f ./crds/volume-modify/
   

3. Run the following command. For details about the component package path, see Table 1.

   kubectl apply -f ./deploy/huawei-csi-controller-extender.yaml
   

4. Run the following command to check whether the services are started.

   kubectl get pod -n huawei-csi
   

   The following is an example of the command output. In the preceding command, huawei-csi indicates the namespace for deploying Huawei CSI.

   NAME                                     READY     STATUS    RESTARTS   AGE
   huawei-csi-controller-6dfcc4b79f-9vjtq   10/10     Running   0          24m
   huawei-csi-node-tqs87                    3/3       Running   0          24m
   

2 - Configuring PVC Changes

The PVC change feature is implemented using CRD. Related resources are described as follows.

Table 1 Resource description

• VolumeModifyClaim resources can be created, deleted, and queried, but cannot be updated.
• VolumeModifyContent resources can only be queried and are used to display the change details of a single PVC. Do not manually create, delete, or modify the resources.
• VolumeModifyContent resources are managed by VolumeModifyClaim. Do not manually manage VolumeModifyContent resources.

2.1 - Creating a PVC Change

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.

2.1.1 - 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

• 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"

2.1.2 - 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

1. Use a remote access tool, such as PuTTY, to log in to any master node in the Kubernetes cluster through the management IP address.

2. Run the following command to create a PVC change.

   kubectl create -f volumemodifyclaim.yaml 
   

3. Query the creation result by following the instructions in Querying a PVC Change.

2.2 - Querying a PVC Change

This section describes how to use Kubectl to query the PVC change status. Currently, Huawei CSI provides the following APIs through CRD.

Querying a VolumeModifyClaim

To query a VolumeModifyClaim using kubectl, perform the following steps.

1. Use a remote access tool, such as PuTTY, to log in to any master node in the Kubernetes cluster through the management IP address.

2. Run the following command to query a PVC change. In the command, vmc-name indicates the name of the VolumeModifyClaim resource.

   kubectl get volumemodifyclaims <vmc-name> -owide
   

   The following is an example of the command output.

   NAME    STATUS      READY   SOURCEKIND     SOURCENAME   STARTEDAT              COMPLETEDAT            AGE
   myvmc   Completed   1/1     StorageClass   mysc         2024-06-06T03:19:13Z   2024-06-06T03:19:16Z   2m2s
   

   Table 1 Command output description

   Parameter	Description
   NAME	VolumeModifyClaim resource name.
   STATUS	VolumeModifyClaim resource status. The value can be: Pending: initial status. Creating: The VolumeModifyClaim has completed basic verification and the server has received the change task, but the task has not been completed. Completed: All associated PVCs are changed. Rollback: When associated PVCs are partially changed, a user deletes PVCs. Deleting: When all associated PVCs are changed, a user deletes PVCs.
   READY	Ratio of the number of changed PVCs to the total number of PVCs that need to be changed.
   SOURCEKIND	Data source type, for example, StorageClass.
   SOURCENAME	Data source name, for example, StorageClass name.
   STARTEDAT	Change start time, that is, the timestamp when the server receives the task and starts to process the task.
   COMPLETEDAT	Change completion time, that is, the timestamp when the changes of all associated PVCs are complete. This parameter exists only when STATUS is Completed.
   AGE	Lifetime of a VolumeModifyClaim from the time when it is created to the current time.

You can use kubectl to view the Events information of a VolumeModifyClaim. If a VolumeModifyClaim cannot meet the creation requirements or an error occurs during the creation, the server will record the Events information. The following command is used as an example:

kubectl describe volumemodifyclaims local-to-hypermetro 

Querying a VolumeModifyContent

A VolumeModifyContent is created using a VolumeModifyClaim and records the change details of a single PVC. To query a VolumeModifyContent using kubectl, perform the following steps:

1. Use a remote access tool, such as PuTTY, to log in to any master node in the Kubernetes cluster through the management IP address.

2. Run the following command to query a PVC change. In the command, myvmc-uid indicates the VolumeModifyContent resource name.

   kubectl get volumemodifycontents myvmc-uid  -owide
   

   The following is an example of the command output.

   NAME         STATUS      MODIFYCLAIMNAME     SOURCEVOLUME   STARTEDAT              COMPLETEDAT            AGE
   myvmc-uid    Completed   myvmc               default/mypvc  2024-06-06T03:19:07Z   2024-06-06T03:19:09Z   36m
   

   Table 2 Command output description

   Parameter	Description
   NAME	VolumeModifyContent resource name. The format is VolumeModifyClaim name-UID of the associated PVC.
   STATUS	VolumeModifyContent resource status. The value can be: Pending: initial status. Creating: The VolumeModifyContent has completed basic verification and the server has received the change task, but the task has not been completed. Completed: The associated PVC is changed. Rollback: The PVC change is being rolled back.
   MODIFYCLAIMNAME	Name of the associated VolumeModifyClaim.
   SOURCEVOLUME	Information about the associated PVC. The format is Namespace name/PVC name.
   STARTEDAT	PVC change start time, that is, the timestamp when the server receives the task and starts to process the task.
   COMPLETEDAT	PVC change completion time, that is, the timestamp when the changes of all associated PVCs are complete. This parameter exists only when STATUS is Completed.
   AGE	Lifetime of a VolumeModifyContent from the time when it is created to the current time.

You can use kubectl to view the Events information of a VolumeModifyContent. If a VolumeModifyContent cannot meet the creation requirements or an error occurs during the PVC change, the server will record the Events information. The following command is used as an example:

kubectl describe volumemodifycontents myvmc-uid

2.3 - Deleting a PVC Change

• If STATUS of a VolumeModifyClaim is Creating, deleting the VolumeModifyClaim resource will delete the created resource on the storage side and then remove the cluster resource. After the deletion, if you continue to use the original StorageClass for PVC management, you need to restore the associated storage backend to a non-HyperMetro storage backend.
• If STATUS of a VolumeModifyClaim is Pending or Completed, deleting the VolumeModifyClaim resource will only remove the cluster resource and will not delete the created resource on the storage side (that is, there is not interaction with the storage side).
• VolumeModifyContent resources are managed by VolumeModifyClaim. Do not manually manage VolumeModifyContent resources.
• If some PVCs among the PVCs to be changed meet the change requirements and the batch change fails, all PVC changes will be removed. As a result, the PVCs that meet the change requirements will not meet the change requirements.
• If a PVC to be changed has been manually managed on the storage side, the change may fail. Do not manually manage storage volumes when using the change feature.

This section describes how to use kubectl to delete a PVC change. The procedure is as follows.

Procedure

1. Use a remote access tool, such as PuTTY, to log in to any master node in the Kubernetes cluster through the management IP address.

2. Run the following command to delete a PVC change. In the command, vmc-name indicates the name of the VolumeModifyClaim resource.

   kubectl delete volumemodifyclaims <vmc-name>
   

3. Query the deletion result by following the instructions in Creating a PVC Change Resource.