Static volume provisioning

Create a pod with a statically provisioned volume:

1. Create a PersistentVolume.
2. Create a PersistentVolumeClaim.
3. Create a pod.

Getting started

1. Install kubect and configure it to work with the new cluster.

2. Find out the unique ID of the disk you are going to use to create a PersistentVolume:

   1. If you do not have a disk yet, create one.

      Warning

      Make sure the disk is located in the same availability zone as the nodes of the group that the pods will be running on.

   2. Get the disk ID (the ID column):

      yc compute disk list
      

      Result:

      +----------------------+------+------------+-------------------+--------+--------------+-------------+
      |          ID          | NAME |    SIZE    |       ZONE        | STATUS | INSTANCE IDS | DESCRIPTION |
      +----------------------+------+------------+-------------------+--------+--------------+-------------+
      | ef3ouo4sgl86******** | k8s  | 4294967296 | ru-central1-a     | READY  |              |             |
      +----------------------+------+------------+-------------------+--------+--------------+-------------+
      

3. Check what storage classes are available and select the appropriate one:

   kubectl get storageclass
   

   Result:

   NAME                          PROVISIONER                    RECLAIMPOLICY  VOLUMEBINDINGMODE     ALLOWVOLUMEEXPANSION  AGE
   yc-network-hdd (default)      disk-csi-driver.mks.ycloud.io  Delete         WaitForFirstConsumer  true                  12d
   yc-network-nvme               disk-csi-driver.mks.ycloud.io  Delete         WaitForFirstConsumer  true                  12d
   yc-network-ssd                disk-csi-driver.mks.ycloud.io  Delete         WaitForFirstConsumer  true                  12d
   yc-network-ssd-nonreplicated  disk-csi-driver.mks.ycloud.io  Delete         WaitForFirstConsumer  true                  12d
   

   Note

   Please note that Kubernetes storage classes and Yandex Compute Cloud disk types are different concepts.

Create a PersistentVolume object

1. Save the PersistentVolume creation specification to a YAML file named test-pv.yaml.

   For more information about the specification, see the Kubernetes documentation.

   When providing the spec.capacity.storage parameter, make sure the exact disk size is specified. Container Storage Interface does not verify disk size for statically provisioned volumes.

   To create a PersistentVolume from an existing cloud drive, enter its unique disk ID in the volumeHandle parameter.

   Note

   If the storageClassName parameter is not specified, the default storage class (yc-network-hdd) is used. To change the default class, see Change the default storage class.

   To learn more about the PersistentVolumeClaim creation specification, see the Kubernetes documentation.

   apiVersion: v1
   kind: PersistentVolume
   metadata:
     name: <PersistentVolume_name>
   spec:
     capacity:
       storage: <PersistentVolume_size>
     accessModes:
       - ReadWriteOnce
     csi:
       driver: disk-csi-driver.mks.ycloud.io
       fsType: ext4
       volumeHandle: <disk_ID>
     storageClassName: <storage_class_name>
   

2. Run this command:

   kubectl create -f test-pv.yaml
   

   Result:

   persistentvolume/<PersistentVolume_name> created
   

3. View the information about the new PersistentVolume object:

   kubectl describe persistentvolume <PersistentVolume_name>
   

   Result:

   Name:            <PersistentVolume_name>
   Labels:          <none>
   Annotations:     <none>
   Finalizers:      [kubernetes.io/pv-protection]
   StorageClass:    <storage_class_name>
   Status:          Available
   ...
   

Create a PersistentVolumeClaim object

1. Save the PersistentVolumeClaim creation specification to a YAML file named test-claim.yaml.

   For more information about the specification, see the Kubernetes documentation.

   apiVersion: v1
   kind: PersistentVolumeClaim
   metadata:
     name: <PersistentVolumeClaim_name>
   spec:
     accessModes:
       - ReadWriteOnce
     resources:
       requests:
         storage: <PersistentVolumeClaim_size>
     storageClassName: <storage_class_name>
     volumeName: <PersistentVolume_name>
   

   Note

   The size of PersistentVolumeClaim must be less than or equal to that of PersistentVolume.

2. Run this command:

   kubectl create -f test-claim.yaml
   

   Result:

   persistentvolumeclaim/<PersistentVolumeClaim_name> created
   

3. View the information about the new PersistentVolumeClaim:

   kubectl describe persistentvolumeclaim <PersistentVolumeClaim_name>
   

   Result:

   Name:          <PersistentVolumeClaim_name>
   Namespace:     default
   StorageClass:  <storage_class_name>
   Status:        Bound
   Volume:        <PersistentVolume_name>
   ...
   

Create a pod with a statically provisioned volume

1. Create a file named test-pod.yaml with a manifest for the pod using PersistentVolumeClaim:

   apiVersion: v1
   kind: Pod
   metadata:
     name: test-pod
   spec:
     containers:
     - name: app
       image: ubuntu
       command: ["/bin/sh"]
       args: ["-c", "while true; do echo $(date -u) >> /data/out.txt; sleep 5; done"]
       volumeMounts:
       - name: persistent-storage
         mountPath: /data
     volumes:
     - name: persistent-storage
       persistentVolumeClaim:
         claimName: <PersistentVolumeClaim_name>
   

   For more information about the specification, see the Kubernetes documentation.

2. Run this command:

   kubectl create -f test-pod.yaml
   

   Result:

   pod/test-pod created
   

3. View the information about the new pod:

   kubectl describe pod test-pod
   

   Result:

   Name:       test-pod
   Namespace:  default
   Priority:   0
   ...
     ----    ------                  ----  ----                     -------
     Normal  Scheduled               20m   default-scheduler        Successfully assigned default/test-pod to cl1jtehftl7q********-icut
     Normal  SuccessfulAttachVolume  20m   attachdetach-controller  AttachVolume.Attach succeeded for volume "<PersistentVolume_name>"
   

In the Compute Cloud management console under Disks, the word Active will appear next to your disk.

How to delete a volume

Disks are not deleted automatically from Compute Cloud when you delete PersistentVolume. To delete the volume completely:

1. Delete the PersistentVolumeClaim object.

   kubectl delete pvc <PersistentVolumeClaim_object_ID>
   

2. Delete the PersistentVolume object.

   kubectl delete pv <PersistentVolume_object_ID>
   

3. In Compute Cloud, delete the disk linked to the PersistentVolume object.