feat: Storage class support

[andyzhangx]

What type of PR is this?
/kind feature

What this PR does / why we need it:
feat: Storage class support

We could provide storage class support even it's static provisioning, and then this driver would pass storage parameters to NodeStageVolume

refer to https://kubernetes-csi.github.io/docs/secrets-and-credentials-storage-class.html

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: smb
provisioner: smb.csi.k8s.io
parameters:
  source: "//smb-server.default.svc.cluster.local/share"
  csi.storage.k8s.io/node-stage-secret-name: "smbcreds"
  csi.storage.k8s.io/node-stage-secret-namespace: "default"
reclaimPolicy: Retain # can only support retain
volumeBindingMode: Immediate

Which issue(s) this PR fixes:

Fixes #60

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Special notes for your reviewer:

Release note:

feat: Storage class support

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[coveralls]

Pull Request Test Coverage Report for Build 165261697

• 8 of 8 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.09%) to 89.25%

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Totals
Change from base Build 164317715:	0.09%
Covered Lines:	631
Relevant Lines:	707

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💛 - Coveralls

[msau42]

Do you really need to provide storageclass support for this? Couldn't you put these fields directly in the PV object?

[andyzhangx]

Do you really need to provide storageclass support for this? Couldn't you put these fields directly in the PV object?

@msau42
provide storage class support is another option, it's quite useful in helm charts, e.g.

helm install --set persistence.storageClass="smb" --set persistence.size=100Gi --generate-name bitnami/wordpress

[andyzhangx]

@msau42 also, I think for nfs driver, it has same requirement, e.g. kubernetes-csi/csi-driver-nfs#30
I will try to provide "dynamic" provisioning for this smb driver, e.g. user brings own samba server, and this driver could provision a new folder under samba server in "dynamic" provisioning stage.

[msau42]

IIUC, the use case for implementing a no-op CreateVolume is to support Helm charts that only know how to create PVCs, instead of manually creating the PV?

[andyzhangx]

IIUC, the use case for implementing a no-op CreateVolume is to support Helm charts that only know how to create PVCs, instead of manually creating the PV?

yes, by providing storage class support, we can use this driver in helm chart or other deployments

[msau42]

Ok, I would clarify that in the docs because that's not the usual expected behavior.

[andyzhangx]

Ok, I would clarify that in the docs because that's not the usual expected behavior.

@msau42 thanks, will do.
Do you think I could port same functionality to nfs csi driver? kubernetes-csi/csi-driver-nfs#30 (comment)

[msau42]

I was thinking of actually having the CreateVolume mount the share to create the subdir, and then unmount it when done, but this would require the provisioner to run as privileged.

I'm not a big fan of not being able to support DeleteVolume, but if there are folks asking for this, we can consider it as a stop-gap solution.