Feature Request: Support VolumeAttributeClass

[y1r]

Describe the solution you'd like

I would like Trident to support VolumeAttributesClass (VAC) to dynamically modify mutable parameters of PVCs. The feature is now generally available in Kubernetes.

Specifically, we want to control the QoS class of ONTAP volumes dynamically (e.g., switching between "gold" and "silver") without changing the StorageClass or migrating the volume.

Regarding the parameter design, we request support for specifying ONTAP QoS Policy Group names (e.g., qosPolicy: "gold") in the VAC, rather than raw IOPS values. This approach enables a Separation of Concerns: Storage Admins can tune the specific IOPS values centrally on ONTAP without requiring updates to Kubernetes objects, while Kubernetes Admins simply manage the Service Level intent ("Gold").

Describe alternatives you've considered

• Using multiple StorageClasses
  • Leads to a combinatorial explosion of StorageClasses ({svm} x {accessMode} x {qos}).
  • Changing QoS requires data migration, which is disruptive and operationally expensive.
• Updating QoS via storage backend CLI (out-of-band)
  • Configuration Drift: The change is hidden from Kubernetes, breaking GitOps workflows and complicating accounting.
  • Reduced Visibility: Operators cannot determine the actual volume state solely through Kubernetes APIs.

Additional context

• https://kubernetes.io/docs/concepts/storage/volume-attributes-classes/

• trident/frontend/csi/controller_server.go

  Lines 1049 to 1054 in cea7ba1

  	func (p *Plugin) ControllerModifyVolume(
  	_ context.Context, _ *csi.ControllerModifyVolumeRequest,
  	) (*csi.ControllerModifyVolumeResponse, error) {
  	// Trident doesn't support ControllerModifyVolume
  	return nil, status.Error(codes.Unimplemented, "")
  	}

[clintonk]

Thank you, @y1r. This feature is on the roadmap, and QoS is indeed an obvious use case.

[y1r]

This feature is on the roadmap, and QoS is indeed an obvious use case.

Thank you for the quick reply.

I'd like to emphasize the importance of supporting QoS Policy Names in VAC for multi-tenant environments. If VAC only supports raw IOPS values (implying per-volume QoS), a tenant can gain unlimited aggregate bandwidth simply by provisioning more volumes. By supporting QoS Policy Names, we can leverage ONTAP's Shared QoS Policy Groups (is-shared=true). This allows admins to enforce a total throughput ceiling (e.g., 1000 IOPS total) for a tenant, regardless of how many volumes they create. This feature is essential for fairness and resource control.

[clintonk]

FWIW, @y1r , Trident only supports QoS via policy names. We could not support raw IOPS, as creation of policies is not available using vsadmin credentials.