Dynamically Mounting an EVS Volume to a StatefulSet

Dynamically mount and use storage volumes. For details about other parameters, see Creating a StatefulSet.

1. Log in to the CCE console and click the cluster name to access the cluster console.
2. In the navigation pane on the left, choose Workloads. Then click the StatefulSets tab.
3. Click Create Workload in the upper right corner. On the displayed page, click Data Storage in the Container Settings area and click Add Volume to select VolumeClaimTemplate.
4. In the upper right corner, click Create PVC. In the displayed dialog box, configure the parameters.
   Click Create.

   Figure 1 Creating a PVC
   

   Parameter	Description
   PVC Type	In this example, select EVS.
   PVC Name	Enter the name of the PVC. After a PVC is created, a suffix is automatically added based on the number of pods. The format is <Custom PVC name>-<Serial number>, for example, example-0.
   Namespace	A namespace is a conceptual grouping of resources or objects. Each namespace provides isolation for data from other namespaces. After a cluster is created, the default namespace is created by default. If there is no special requirement, select the default namespace.
   Creation Method	You can select Dynamically provision to create a PVC, PV, and underlying storage on the console in cascading mode.
   Storage Classes	The StorageClass for EVS volumes is csi-disk.
   (Optional) PV Name Prefix	This parameter specifies the name of the underlying storage that is automatically created. The actual underlying storage name is in the format of "PV name prefix + PVC UID". If this parameter is left blank, the default prefix pvc will be used. For example, if the storage volume name prefix is set to test, the actual underlying storage name is test-{UID}.
   AZ	Select the AZ of the EVS disk. After the EVS disk is created, the AZ cannot be changed. In this example, select AZ3.
   Disk Type	Select an EVS disk type. EVS disk types vary depending on regions. Obtain the available EVS types on the console. In this example, select High I/O. NOTE: General-purpose SSD V2 disks allow you to specify the disk IOPS and throughput. For details, see EVS performance data.
   Capacity (GiB)	Capacity of the requested storage volume. Set it to 10 in this example.
   Access Mode	EVS volumes support only ReadWriteOnce, indicating that a storage volume can only be mounted to one pod in read/write mode. For details, see Volume Access Modes.
   Encryption	Configure whether to encrypt underlying storage. If you select Enabled (key), an encryption key must be configured. Currently, encryption is not supported.
   Enterprise Project	The default enterprise project, the enterprise project to which the cluster belongs, or the enterprise project specified by StorageClass is available.
   Resource Tag	You can add resource tags to classify resources. You can create predefined tags on the TMS console. The predefined tags are available to all resources that support tags. You can use predefined tags to improve the tag creation and resource migration efficiency. For details, see Creating Predefined Tags. CCE automatically creates system tags CCE-Cluster-ID={Cluster ID}, CCE-Cluster-Name={Cluster name}, and CCE-Namespace={Namespace name}. These tags cannot be modified. NOTE: After a dynamic PV of the EVS type is created, the resource tags cannot be updated on the CCE console. To update these resource tags, go to the EVS console.

5. Enter the path to which the volume is mounted.

   In this example, the volume is mounted to the /data path of the container. The container data generated in this path is stored in the EVS disk.

   Figure 2 Parameters for mounting a storage volume
   

   Table 1 Parameters for mounting a storage volume

   Parameter	Description
   Mount Path	Enter a mount path, for example, /data. This parameter indicates the container path that the volume will be mounted to. Do not mount the volume to a system directory such as / or /var/run. This may cause container errors. Mount the volume to an empty directory. If the directory is not empty, ensure that there are no files that affect container startup. If there are such files, they will be replaced, which will lead to a container startup or workload creation failure. NOTICE: If a volume is mounted to a high-risk directory, use an account with minimum permissions to start the container, or high-risk files on the host may be damaged.
   Subpath	Enter the subpath of the storage volume and mount a path in the storage volume to the container. In this way, different folders of the same storage volume can be used in a single pod. data, for example, indicates that data in the mount path of the container is stored in the data directory of the storage volume. If this parameter is left blank, the root path is used by default.
   Permission	Read-only: You can only read the data in the mounted volume. Read-write: You can modify the volume mounted to the path. Newly written data will not be migrated if the container is migrated, which may cause data loss.

6. Configure other parameters and click Create Workload. After the workload is created, the data in the container mount directory will be persistently stored. Verify the storage by referring to Verifying Data Persistence.

1. Use kubectl to connect to the cluster.
2. Create a file named statefulset-evs.yaml. In this example, the EVS volume is mounted to the /data path.

   apiVersion: apps/v1
   kind: StatefulSet
   metadata:
     name: statefulset-evs
     namespace: default
   spec:
     selector:
       matchLabels:
         app: statefulset-evs
     template:
       metadata:
         labels:
           app: statefulset-evs
       spec:
         containers:
           - name: container-1
             image: nginx:latest
             volumeMounts:
               - name: pvc-disk           # The value must be the same as that in the volumeClaimTemplates field.
                 mountPath: /data         # Location where the storage volume is mounted
         imagePullSecrets:
           - name: default-secret
     serviceName: statefulset-evs         # Headless Service name
     replicas: 2
     volumeClaimTemplates:
       - apiVersion: v1
         kind: PersistentVolumeClaim
         metadata:
           name: pvc-disk
           namespace: default
           annotations:
             everest.io/disk-volume-type: SAS    # EVS disk type
             everest.io/enterprise-project-id: <your_project_id>  # (Optional) Enterprise project ID. If an enterprise project is specified, use the same enterprise project when creating a PVC. Otherwise, the PVC cannot be bound to a PV.
             everest.io/disk-iops: '3000'      # (Optional) IOPS of only a GPSSD2 EVS disk
             everest.io/disk-throughput: '125' # (Optional) Throughput of only a GPSSD2 EVS disk
             everest.io/csi.volume-name-prefix: test  # (Optional) Storage volume name prefix of the automatically created underlying storage
           labels:
             failure-domain.beta.kubernetes.io/region: <your_region>   # Replace the region with the one where the cluster is located.
             failure-domain.beta.kubernetes.io/zone: <your_zone>       # Replace the AZ with the one where the EVS disk is located.
         spec:
           accessModes:
             - ReadWriteOnce               # The value must be ReadWriteOnce for EVS disks.
           resources:
             requests:
               storage: 10Gi             # EVS disk capacity, in GiB. The value ranges from 1 to 32768.
           storageClassName: csi-disk    # The StorageClass of the EVS disk
   ---
   apiVersion: v1
   kind: Service
   metadata:
     name: statefulset-evs   # Headless Service name
     namespace: default
     labels:
       app: statefulset-evs
   spec:
     selector:
       app: statefulset-evs
     clusterIP: None
     ports:
       - name: statefulset-evs
         targetPort: 80
         nodePort: 0
         port: 80
         protocol: TCP
     type: ClusterIP

   Table 2 Key parameters

   Parameter	Mandatory	Description
   failure-domain.beta.kubernetes.io/region	Yes	Region of the cluster. For example, cn-east-3. For details, see Regions and Endpoints.
   failure-domain.beta.kubernetes.io/zone	Yes	AZ of the EVS disk. You can obtain all supported AZs by querying the AZ list.
   everest.io/disk-volume-type	Yes	EVS disk type. All letters are in uppercase. EVS disk types vary depending on regions. Obtain the available EVS types on the console. SAS: high I/O SSD: ultra-high I/O GPSSD: general-purpose SSD ESSD: extreme SSD GPSSD2: general-purpose SSD v2. You need to specify the everest.io/disk-iops and everest.io/disk-throughput annotations.
   everest.io/disk-iops	No	Preconfigured IOPS, which is supported only by general-purpose SSD v2 EVS disks. The IOPS of general-purpose SSD v2 EVS disks ranges from 3000 to 128000, and the maximum value is 500 times of the capacity (GiB). If the IOPS of general-purpose SSD v2 disks is greater than 3000, extra IOPS will be billed. For details, see Price Calculator.
   everest.io/disk-throughput	No	Preconfigured throughput, which is supported only by general-purpose SSD v2 EVS disks. The value ranges from 125 MiB/s to 1,000 MiB/s. The maximum value is a quarter of IOPS. If the throughput is greater than 125 MiB/s, extra throughput will be billed. For details, see Price Calculator.
   everest.io/enterprise-project-id	No	Enterprise project ID of the EVS disk. This parameter is optional. If an enterprise project is specified, use the same enterprise project when creating a PVC, or the PVC cannot be bound to a PV. To obtain an enterprise project ID, log in to the EPS console, click the name of the target enterprise project, and copy the enterprise project ID.
   everest.io/disk-volume-tags	No	You can add resource tags to classify resources. This field is optional. You can create predefined tags on the TMS console. The predefined tags are available to all resources that support tags. You can use predefined tags to improve the tag creation and resource migration efficiency. For details, see Creating Predefined Tags. CCE automatically creates system tags CCE-Cluster-ID={Cluster ID}, CCE-Cluster-Name={Cluster name}, and CCE-Namespace={Namespace name}. These tags cannot be modified.
   everest.io/csi.volume-name-prefix	No	This parameter is optional. It specifies the name of the underlying storage that is automatically created. The actual underlying storage name is in the format of "PV name prefix + PVC UID". If this parameter is left blank, the default prefix pvc will be used. Enter 1 to 26 characters that cannot start or end with a hyphen (-). Only lowercase letters, digits, and hyphens (-) are allowed. For example, if the storage volume name prefix is set to test, the actual underlying storage name is test-{UID}.
   storage	Yes	Requested PVC capacity, in Gi. The value ranges from 1 to 32768.
   storageClassName	Yes	The StorageClass for EVS volumes is csi-disk.

3. Run the following command to create a workload that the EVS volume is mounted to:

   kubectl apply -f statefulset-evs.yaml

   After the workload is created, the data in the container mount directory will be persistently stored. Verify the storage by referring to Verifying Data Persistence.