Addenda02

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ADDENDA 2: Specify a default storage class

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GOAL:
Most of the volume requests in this lab refer to a specific storage class.
Setting a default storage class can be useful, especially when this one is used most times. This also allows you not to set the storage class parameter in the Volume Claim anymore.

A. Set a default storage class

$ kubectl get sc
NAME                          PROVISIONER             RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
storage-class-iscsi         csi.trident.netapp.io   Delete          Immediate           true                   75d
storage-class-nfs           csi.trident.netapp.io   Delete          Immediate           true                   75d
storage-class-nvme          csi.trident.netapp.io   Delete          Immediate           true                   75d
storage-class-smb           csi.trident.netapp.io   Delete          Immediate           true                   75d

$ kubectl patch storageclass storage-class-nfs -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'
storageclass.storage.k8s.io/storage-class-nfs patched

$ kubectl get sc
NAME                          PROVISIONER             RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
storage-class-iscsi           csi.trident.netapp.io   Delete          Immediate           true                   75d
storage-class-nfs (default)   csi.trident.netapp.io   Delete          Immediate           true                   75d
storage-class-nvme            csi.trident.netapp.io   Delete          Immediate           true                   75d
storage-class-smb             csi.trident.netapp.io   Delete          Immediate           true                   75d

As you can see, storage-class-nfs is now refered as the default SC for this cluster.

B. Try this new setup

There is a PVC file in this directory. If you look at it, you will see there is no SC set.

$ kubectl create -f 1_pvc.yaml
persistentvolumeclaim/pvc-without-sc created

$ kubectl get pvc,pv
NAME                                   STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS        VOLUMEATTRIBUTESCLASS   AGE
persistentvolumeclaim/pvc-without-sc   Bound    pvc-17c42930-9bf6-4ef6-abc8-d65400140699   5Gi        RWX            storage-class-nfs   <unset>                 15s

NAME                                                        CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                    STORAGECLASS        VOLUMEATTRIBUTESCLASS   REASON   AGE
persistentvolume/pvc-17c42930-9bf6-4ef6-abc8-d65400140699   5Gi        RWX            Delete           Bound    default/pvc-without-sc   storage-class-nfs   <unset>                          13s

If you take a closer look at the get pv result, you will see that it shows the storage class against which it was created, which is also the default one.

$ kubectl delete pvc pvc-without-sc
persistentvolumeclaim "pvc-without-sc" deleted

C. What's next

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