User Story

As a user, I want to have the ability to create Persistent Volume Claims (PVCs) which can dynamically bind to a StorageClass backed by Azure Ultra Disk so that I can mount them successfully to Pods for my workloads needs.

As an Openshift developer I'd like this feature to be present in the upstream kubernetes-sigs/cluster-api-provider-azure (CAPZ) so than I can port it downstream and keep a similar approach.

Background

It would be useful to enable the ultra disk capability on the VMs when no data disks are attached.

The Azure CSI driver has the ability to provision ultra disk based persistent volumes, but for this to work, the VMs that the PVs are attached to must have the AdditionalCapabilities.UltraSSDEnabled set to true.

When CAPZ creates a VM today, there is no way to explicitly enable this capability. This is only enabled when a ultra disk data disk is defined within the machine spec.

We should add a new field to the machine spec to allow this feature to be explicitly enabled

More details: https://github.com/kubernetes-sigs/cluster-api-provider-azure/issues/1852 and https://kubernetes.slack.com/archives/CEX9HENG7/p1636564271163800

Steps

• Agree on an API design and an approach with the maintainers of the project
• Create PR and get it merged

Stakeholders

• Cluster Infrastructure (cloud) team
• Upstream CAPZ community

Definition of Done

• PR with the feature merged upstream
• Docs
• Testing