tencent cloud

A cluster admin can use StorageClass to define different storage classes for Tencent Kubernetes Engine (TKE) clusters. TKE provides the block storage StorageClass by default. You can use both StorageClass and PersistentVolumeClaim to dynamically create required storage resources. This document describes how to create a StorageClass of the Cloud Block Storage (CBS) type by using the console and Kubectl, and how to customize the template required by CBS disks.

Console Operation Directions

Creating StorageClass

1. Log in to the TKE console and click Cluster in the left sidebar.
2. Click the ID of the cluster for which a StorageClass needs to be created to go to the cluster details page.
3. Click Storage > StorageClass in the left sidebar, as shown in the following figure.
   
4. Click Create to go to the Create StorageClass page, where you can set the parameters as required, as shown in the following figure.
   
   The main parameters are described as follows:
   • Name: Set a custom name. This document uses cbs-test as an example.
   • Provisioner: Select Cloud Block Storage.
   • Region: The region where the current cluster is located.
   • Availability zone: Select the availability zones that support CBS disks in the current region as required.
   • Billing mode: The pay-as-you-go billing mode is provided. It allows you to enable and terminate instances at any time. The instances are billed based on actual usage, and the Delete and Retain reclaim policies are supported.
   • Disk type: Premium Cloud Disk, SSD Cloud Disk, and Enhanced SSD Cloud Disk are supported. Different availability zones may have different disk types. For more information, see Cloud Disk Types. Select a disk type as prompted by the console.
   • Reclaim policy: The reclaim policy for cloud disks. Generally, the Delete and Retain reclaim policies are provided, which depends on the selected billing mode. For data security, we recommend that you select Retain.
   • Volume binding mode: The modes of Bind now and Wait for scheduling are available. Different modes support different volume binding policies. Refer to the following information to select the appropriate mode:
     • Bind now: PVCs created via the storageclass will be directly bound with the PV and allocated.
     • Wait for scheduling: PVCs created via the storageclass will not be bound with the PV and allocated until the pod that uses the PVCs is created.
   • Scheduled snapshot: Setting scheduled snapshot policy can effectively protect data security, but data backup will generate certain fees. For more information, see Snapshot Overview.

     Note：

     The default-policy configuration provided by TKE for backup includes the date of backup execution, time point of backup execution, and backup retention period.

5. Click Create a StorageClass to complete the process.

Creating a PVC by using a specified StorageClass

1. On the Cluster management page, select the ID of the cluster for which a PVC needs to be created.
2. On the cluster details page, choose Storage > PersistentVolumeClaim in the left sidebar to go to the PersistentVolumeClaim page, as shown in the following figure.
   
3. Click Create to go to the Create a PersistentVolumeClaim page, where you can set key PVC parameters as required, as shown in the following figure.
   
   The main parameters are described as follows:
   • Name: set a custom name. This document uses cbs-pvc as an example.
   • Namespace: Select default.
   • Provisioner: Select Cloud Block Storage.
   • R/W permission: CBS disks only support Single machine read and write.
   • StorageClass: Specify a StorageClass as required. This document uses the cbs-test created in the step of Creating a StorageClass as an example.

     Note：

     • The PVC and PV will be bound to the same StorageClass.
     • If you do not specify a StorageClass, the value of StorageClass for the corresponding PVC is empty, and the value of the storageClassName field in the corresponding YAML file is a null string.

   • PersistVolume: Specify a PersistentVolume as required. In the example in this document, no PersistentVolume is specified.

     Note：

     • The system first searches the current cluster to see whether there are PVs that meet the binding rules. If no, the system dynamically creates a PV to be bound based on the PVC and the selected StorageClass.
     • If StorageClass is not specified, then PersistVolume must be specified.
     • No PersistentVolume is specified. For more information, see PV and PVC Binding Rules.

   • Disk type: Based on the selected StorageClass, the available disk types are displayed: Premium Cloud Disk, SSD Cloud Disk and Enhanced SSD Cloud Disk.
   • Capacity: When PersistentVolume is not specified, you need to indicate the desired capacity of the cloud disk. The capacity must be a multiple of 10. For premium cloud disk, the minimum capacity is 10 GB, and for SSD cloud disk and enhance SSD cloud disk, the minimum capacity is 20 GB.
   • Cost: Based on the above parameters, calculate the cost of the corresponding cloud disk. For more information, see Billing Modes.
4. Click Create a PersistentVolumeClaim to complete the creation.

Creating a StatefulSet to mount a PVC volume

Note：

This step creates a StatefulSet workload as an example.

1. On the details page of the desired cluster, choose Workload > StatefulSet in the left sidebar to go to the StatefulSet page.
2. Click Create to go to the Create Workload page. For more information, see Creating a StatefulSet. Then, mount a volume as required, as shown in the following figure.
   
   • Volume (optional):
     • Mount method: Select Use existing PVC.
     • Volume name: Set a custom name. This document uses cbs-vol as an example.
     • Select PVC: Select an existing PVC. This document uses the cbs-pvc, which you created in the step of Creating a PVC by using a specified StorageClass, as an example.
   • Containers in the Pod: Click Add mount target to set a mount target.
     • Volume: Select the volume cbs-vol that you added in this step.
     • Destination path: Enter a destination path. This document uses /cache as an example.
     • Sub-path: Mount only a sub-path or a single file in the selected volume, such as /data or /test.txt.
3. Click Create Workload to complete the process.

   Note：

   If you use the PVC mount method of CBS, the volume can be mounted to only one node.

Kubectl Operation Directions

You can use the sample template in this document to create a StorageClass by using Kubectl.

Creating a StorageClass

The following sample YAML file is used to create a StorageClass with the default name of cbs in a cluster.

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
 # annotations:
 #   storageclass.beta.kubernetes.io/is-default-class: "true"
 # If this line is present, it will become the default-class, and if you do not specify a type when creating a PVC, this type will be used automatically.
  name: cloud-premium
# If the CBS-CSI add-on is installed for the TKE cluster, enter `com.tencent.cloud.csi.cbs` for `provisioner`.
# If the CBS-CSI add-on is not installed, enter `cloud.tencent.com/qcloud-cbs` for `provisioner` (this capability is deprecated in v1.20 and later versions).
provisioner: com.tencent.cloud.csi.cbs 
parameters:
  type: CLOUD_PREMIUM
  renewflag: NOTIFY_AND_AUTO_RENEW
  paymode: POSTPAID_BY_HOUR
  aspid: asp-123
reclaimPolicy: Retain
volumeBindingMode: WaitForFirstConsumer

The following table lists the supported parameters.

Creating a multi-Pod StatefulSet

You can use a cloud disk to create a multi-pod StatefulSet. The sample YAML file is as follows:

The apiVersion of the resource object varies based on the cluster Kubernetes version. You can run the command kubectl api-versions to view the apiVersion of the current resource object.

apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 selector:
   matchLabels:
     app: nginx
 serviceName: "nginx"
 replicas: 3
 template:
   metadata:
     labels:
       app: nginx
   spec:
     terminationGracePeriodSeconds: 10
     containers:
     - name: nginx
       image: nginx
       ports:
       - containerPort: 80
         name: web
       volumeMounts:
       - name: www
         mountPath: /usr/share/nginx/html
 volumeClaimTemplates: # the system automatically creates a PVC and then automatically creates a PV.
 - metadata:
     name: www
   spec:
     accessModes: [ "ReadWriteOnce" ]
     storageClassName: cloud-premium
     resources:
       requests:
         storage: 10Gi