Mount option "dataCenter" (automatic?)

[Ruakij]

I'd like to add the mount-option "dataCenter" from weed mount.
It should be able to get added to StorageClass parameters and PersistentVolume.

Is this just a matter of adding it to the mounter?

And if so, where?
This comment gave me some hesitation, but i didnt find a better suited location while looking.
Is volumeAttributes from PersistentVolume and parameters from StorageClass both volContext?

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I'd also like to add an automatic selector for the dataCenter based on the dataCenter the current pod is running in.
Node-Label topology.kubernetes.io/zone (Documentation) could be used?
Maybe have this option enabled by-default?

Is it ok to set this in mounter_seaweedfs.go?

That would also pave the first step towards "Topology-aware volume provisioners".

Read:
Blog-Post:https://kubernetes.io/blog/2018/10/11/topology-aware-volume-provisioning-in-kubernetes/
K8s-Documentation: https://kubernetes.io/docs/concepts/storage/storage-classes/#volume-binding-mode
CSI-documentation: https://kubernetes-csi.github.io/docs/topology.html

[chrislusf]

Is volumeAttributes from PersistentVolume and parameters from StorageClass both volContext?

Need a k8s expert on this.

[Ruakij]

Have tested, yes its the same.
Not sure why they named it differently..

[chrislusf]

seems the same thing but controlled at different level.

storage class sounds a type of storage, while PersistentVolume seems a specific instance of the storage type.

[Ruakij]

I think there is a bug in mapping the volContext-parameters to mount-args?

In mounter_seaweedfs.go, diskType is translated to disk, but the mount-option for weed mount is called diskType.

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Is it okay if i remove the selective-mapping from Line 89 - 96 and simply add any volContext as args?
Special operations like for volumeCapacity will of course be kept.

This enables setting any mount-options (like dataCenter, currently missing) using the context without having to add them manually in the code.
Of course this also allows misconfiguration, but which can be found quickly using the container logs from seaweedfs-csi-driver-node.

[chrislusf]

you can remove 89-94 and add a default section.