vSphere Container Storage Plug-in supports dynamic volume provisioning for block volumes. When you use the dynamic volume provisioning, you can create storage volumes on demand in native Kubernetes clusters.
When you provision volumes dynamically, consider the following items:
- Block volumes can be provisioned using
ReadWriteOnce access mode in the PersistentVolumeClaim specification. Volumes created using PersistentVolumeClaim with ReadWriteOnce access mode should be used by a single pod. vSphere Container Storage Plug-in does not support creating multiple pods using the PersistentVolumeClaim with ReadWriteOnce access mode.
- Dynamic volume provisioning allows you to create storage volumes on demand.
- Without dynamic volume provisioning, cluster administrators have to manually make calls to their cloud or storage provider to create new storage volumes, and then create PersistentVolume objects to represent them in Kubernetes.
- With dynamic volume provisioning, cluster administrators do not need to pre-provision backing storage. Instead, the dynamic provisioning automatically provisions storage when it is requested by users.
- The implementation of dynamic volume provisioning is based on the API object
StorageClass from the API group storage.k8s.io.
- A cluster administrator can define as many
StorageClass objects as required. Each StorageClass can specify a volume plug-in provisioner that provisions a volume, and a set of parameters.
- A cluster administrator can define and expose multiple types of storage within a cluster by using custom set of parameters. Types of storage can be from the same or different storage systems.
For more information on provisioning volumes using topology and use of the
WaitForFirstConsumer volumeBinding mode with dynamic volume provisioning, see
Topology-Aware Volume Provisioning.
Note: Support for volume topology is present only in Vanilla Kubernetes for single-access (RWO) file system based volume.
You can provision a PersistentVolume dynamically on a native Kubernetes cluster by using the following steps.
Procedure
- Define a Storage Class.
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: example-sc
annotations:
storageclass.kubernetes.io/is-default-class: "true"
provisioner: csi.vsphere.vmware.com
parameters:
storagepolicyname: "vSAN Default Storage Policy" #Optional Parameter
# datastoreurl: "ds:///vmfs/volumes/vsan:52cdfa80721ff516-ea1e993113acfc77/" #Optional Parameter
# csi.storage.k8s.io/fstype: "ext4" #Optional Parameter
- Import this
StorageClass into the native Kubernetes cluster.
kubectl create -f example-sc.yaml
- Define a
PersistentVolumeClaim request.
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: example-pvc
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 5Gi
storageClassName: example-sc
- Import the
PersistentVolumeClaim into the Vanila Kubernetes cluster.
kubectl create -f example-pvc.yaml
- Verify that the
PersistentVolumeClaim has been created and has a PersistentVolume attached to it.
$ kubectl describe pvc example-pvc
Name: example-pvc
Namespace: default
StorageClass: example-sc
Status: Bound
Volume: pvc-7ed39d8e-7896-11ea-a119-005056983fec
Labels: <none>
Annotations: pv.kubernetes.io/bind-completed: yes
pv.kubernetes.io/bound-by-controller: yes
volume.beta.kubernetes.io/storage-provisioner: csi.vsphere.vmware.com
Finalizers: [kubernetes.io/pvc-protection]
Capacity: 5Gi
Access Modes: RWO
VolumeMode: Filesystem
Mounted By: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Provisioning 50s csi.vsphere.vmware.com_vsphere-csi-controller-7777666589-jpnqh_798e6967-2ce1-486f-9c21-43d9dea709ae External provisioner is provisioning volume for claim "default/example-pvc"
Normal ExternalProvisioning 20s (x3 over 50s) persistentvolume-controller waiting for a volume to be created, either by external provisioner "csi.vsphere.vmware.com" or manually created by system administrator
Normal ProvisioningSucceeded 8s csi.vsphere.vmware.com_vsphere-csi-controller-7777666589-jpnqh_798e6967-2ce1-486f-9c21-43d9dea709ae Successfully provisioned volume pvc-7ed39d8e-7896-11ea-a119-005056983fec
When successfully created, the
Status section shows
Bound and the
Volume field is populated.
A PersistentVolume is automatically created, and is bound to this PersistentVolumeClaim.
In this example, RWO access mode indicates that the volume is created on a vSphere virtual disk (First Class Disk).
- Verify that
PersistentVolume has been successfully created for the PersistentVolumeClaim.
$ kubectl describe pv pvc-7ed39d8e-7896-11ea-a119-005056983fec
Name: pvc-7ed39d8e-7896-11ea-a119-005056983fec
Labels: <none>
Annotations: pv.kubernetes.io/provisioned-by: csi.vsphere.vmware.com
Finalizers: [kubernetes.io/pv-protection]
StorageClass: example-sc
Status: Bound
Claim: default/example-pvc
Reclaim Policy: Delete
Access Modes: RWO
VolumeMode: Filesystem
Capacity: 5Gi
Node Affinity: <none>
Message:
Source:
Type: CSI (a Container Storage Interface (CSI) volume source)
Driver: csi.vsphere.vmware.com
VolumeHandle: e4073a6d-642e-4dff-8f4a-b4e3a47c4bbd
ReadOnly: false
VolumeAttributes: storage.kubernetes.io/csiProvisionerIdentity=1586239648866-8081-csi.vsphere.vmware.com
type=vSphere CNS Block Volume
Events: <none>
If successfully created,
PersistentVolume is available in the output, and
VolumeHandle key is populated.
The Status must display as Bound. You can also see that the Claim is set to the above PersistentVolumeClaim name example-pvc.
