Declaring more than one default StorageClass

[museg27]

Hi!
There is discrepancies in the documentation for behavior of creating a PersistentVolumeClaim when declaring more than one default StorageClass :

in
https://kubernetes.io/docs/tasks/administer-cluster/change-default-storage-class/#changing-the-default-storageclass

"Please note that at most one StorageClass can be marked as default. If two or more of them are marked as default, a PersistentVolumeClaim without storageClassName explicitly specified cannot be created."

and
https://kubernetes.io/docs/concepts/storage/storage-classes/#default-storageclass

"If you set the storageclass.kubernetes.io/is-default-class annotation to true on more than one StorageClass in your cluster, and you then create a PersistentVolumeClaim with no storageClassName set, Kubernetes uses the most recently created default StorageClass."

Thank you.

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[thisisharrsh]

/language en
/sig docs

[thisisharrsh]

/sig storage

[thisisharrsh]

master_node $ kubectl describe pvc test-pvc
Name:          test-pvc
Namespace:     default
StorageClass:  default-class-two
Status:        Pending
Volume:        
Labels:        <none>
Annotations:   <none>
Finalizers:    [kubernetes.io/pvc-protection]
Capacity:      
Access Modes:  
VolumeMode:    Filesystem
Used By:       <none>
Events:
  Type    Reason                Age               From                         Message
  ----    ------                ----              ----                         -------
  Normal  WaitForFirstConsumer  4s (x2 over 15s)  persistentvolume-controller  waiting for first consumer to be created before binding

Based on the output, the StorageClass default-class-two was selected for the test-pvc, confirming that Kubernetes chose the most recently created default StorageClass.

[thisisharrsh]

I believe we should change the current documentation in the Changing the default StorageClass to:
If two or more StorageClasses are marked as default, Kubernetes uses the most recently created default StorageClass for PersistentVolumeClaims without a specified storageClassName.

[thisisharrsh]

I would to like to work on this issue.
/assign

[iheartNathan]

#48200 was created to fix this.