A user cluster has one or more StorageClass objects, and one of them is designated as the default StorageClass. This page shows how to set the default StorageClass for a user cluster.
For more information, see Storage.
Find the default StorageClass
List all the StorageClasses:
kubectl --kubeconfig USER_CLUSTER_KUBECONFIG get storageclasses
In the output, you can see which StorageClass is the default. For example, in
the following output, you can see that a StorageClass named standard-rwo is
the default StorageClass:
standard kubernetes.io/vsphere-volume standard-rwo (default) csi.vsphere.vmware.com
When you request storage, you can specify a StorageClass. If you do not specify a StorageClass, the default StorageClass is used. For example, suppose you create a PersistentVolumeClaim that does not specify a StorageClass. The volume controller will fulfill the claim according to the default StorageClass.
Changing the default StorageClass
As a cluster administrator, you might want to change the default storage class. Then all requests for storage that do not specify a StorageClass will be fulfilled according to the StorageClass of your choice. This section gives the steps for changing the default.
Deploy a new storage system
Deploy a new storage system and any software components for integrating the new storage mechanism with a Kubernetes cluster. For example, you might need to install a CSI driver in the cluster.
This step depends on the storage vendor you're using. For CSI drivers, vendors should provide instructions for deploying their CSI driver to a Kubernetes cluster. A CSI driver's documentation should also include the driver-specific parameters that you provide in your StorageClass, including the provisioner name.
When you create a StorageClass for your new appliance, you should name the StorageClass after its properties (such as "fast" or "highly-replicated"), rather than after the name of the specific driver or appliance behind it. This will make it easier to have consistent storage policies across clusters and environments.
Remove the default annotation from the default StorageClass
Open the default StorageClass in a text editor:
kubectl --kubeconfig [USER_CLUSTER_KUBECONFIG] edit storageclass \
DEFAULT_STORAGE_CLASS
In the text editor, remove the
storageclass.kubernetes.io/is-default-class: "true" annotation. Close the
text editor.
To verify that the annotation was removed, enter this command:
kubectl --kubeconfig [USER_CLUSTER_KUBECONFIG] get storageclass \
DEFAULT_STORAGE_CLASS --output yaml
Create a new StorageClass
Create a manifest for a new StorageClass.
Include the storageclass.kubernetes.io/is-default-class: "true" annotation.
For example:
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
annotations:
storageclass.kubernetes.io/is-default-class: "true"
...
name: my-storage-class
...
parameters:
...
provisioner: [MY_PROVISIONER]
...
Save your manifest as a YAML file, and create the new StorageClass:
kubectl --kubeconfig [CLUSTER_KUBECONFIG] apply -f [MANIFEST_FILE]
where [MANIFEST_FILE] is the path to your new StorageClass manifest file.