fix(azure): set DiskControllerType in StorageProfile for RHEL AI VMs

[rishupk]

RHEL AI VMs on certain instance families (Standard_L8aos_v4 and others) fail at boot because Azure infers NVMe as the disk controller type, but the gallery images only work with SCSI. This sets DiskControllerType: "SCSI" in StorageProfile through a new field on ImageReference. It also reads the disk controller types from the gallery image definition and filters compute sizes at allocation — spot and non-spot — so an incompatible size fails with a clear error before Azure ever sees the request.

Co-Authored-By: Claude <Sonnet 4.6> noreply@anthropic.com
Signed-off-by: Rishabh Kothari rkothari@redhat.com

[coderabbitai]

Warning

Review limit reached

@rishupk, we couldn't start this review because you've reached your PR review rate limit.

More reviews will be available in 59 minutes and 57 seconds. Learn how PR review limits work.

Your organization has run out of usage credits. Purchase more in the billing tab.

⌛ How to resolve this issue?

After more reviews become available, a review can be triggered using the @coderabbitai review command as a PR comment. Alternatively, push new commits to this PR.

We recommend that you space out your commits to avoid hitting the rate limit.

🚦 How do rate limits work?

CodeRabbit enforces hourly rate limits for each developer per organization.

Our paid plans include higher PR review limits than trial, open-source, and free plans. In all cases, reviews become available again over time. During sustained high-volume PR review activity, CodeRabbit may temporarily slow when the next review becomes available.

Please see our Fair Usage Limits Policy for further information.

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Enterprise

Run ID: c6f9b653-d3c1-42f2-8873-4758f1c29fa5

📥 Commits

Reviewing files that changed from the base of the PR and between 35fba64 and 9da27f0.

📒 Files selected for processing (7)

• pkg/provider/azure/action/rhel-ai/rhelai.go
• pkg/provider/azure/data/compute-request.go
• pkg/provider/azure/data/imageref.go
• pkg/provider/azure/data/images.go
• pkg/provider/azure/data/util.go
• pkg/provider/azure/modules/allocation/allocation.go
• pkg/provider/azure/modules/virtual-machine/virtual-machine.go

📝 Walkthrough

Walkthrough

This PR adds disk controller type support to Azure VM allocation and creation. It introduces data model fields for storing disk controller types, Azure API functions for querying SKU and image capabilities, allocation logic to filter compute sizes by disk controller compatibility, and VM resource wiring to set the disk controller type on created instances.

Changes

Disk Controller Type Support

Layer / File(s)	Summary
Data model and utility functions pkg/provider/azure/data/imageref.go, pkg/provider/azure/data/util.go	ImageReference struct gains DiskControllerType field; splitDiskControllerTypes helper parses comma-separated controller type strings.
Azure API querying for disk controller types pkg/provider/azure/data/images.go, pkg/provider/azure/data/compute-request.go	GetSharedImageDiskControllerTypes queries Azure Shared Image definitions for disk controller capabilities; FilterComputeSizesByDiskControllerType filters compute SKUs by controller type availability in a location.
Allocation filtering and image reference resolution pkg/provider/azure/modules/allocation/allocation.go	Allocation derives effective image references via resolveImageRef and filters both spot and non-spot compute sizes by disk controller type, returning compatible sizes or explicit errors.
VM resource creation with disk controller type pkg/provider/azure/action/rhel-ai/rhelai.go, pkg/provider/azure/modules/virtual-machine/virtual-machine.go	RHEL-AI action sets disk controller type to SCSI on image reference; VM module wires disk controller type to Pulumi OS disk parameters via diskControllerTypePtr helper.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 41.18% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: setting DiskControllerType in StorageProfile for RHEL AI VMs, which aligns directly with the changeset's primary objective.
Description check	✅ Passed	The description is directly related to the changeset, explaining the problem (RHEL AI VMs fail on certain instance families due to disk controller type mismatch), the solution (setting DiskControllerType to SCSI), and additional improvements (reading from gallery and filtering compute sizes).
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@pkg/provider/azure/data/images.go`:
- Around line 101-103: The code currently uses AZURE_SUBSCRIPTION_ID to build
the compute client (subscriptionId -> armcompute.NewClientFactory), but for
shared/gallery images you must extract the subscription from the image ARM
resource ID (the variable id) instead of the caller default; update the logic in
images.go to parse the subscription segment from the image ARM ID (id), assign
that to subscriptionId and pass it into
armcompute.NewClientFactory(idSubscription, cred, nil) so cross-subscription
gallery images create the correct client and do not silently disable
enrichment/filtering.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Enterprise

Run ID: 1d9bb72a-065d-44ba-a841-e2c4fa789abb

📥 Commits

Reviewing files that changed from the base of the PR and between 7c5d50d and 35fba64.

📒 Files selected for processing (7)

• pkg/provider/azure/action/rhel-ai/rhelai.go
• pkg/provider/azure/data/compute-request.go
• pkg/provider/azure/data/imageref.go
• pkg/provider/azure/data/images.go
• pkg/provider/azure/data/util.go
• pkg/provider/azure/modules/allocation/allocation.go
• pkg/provider/azure/modules/virtual-machine/virtual-machine.go

[rishupk]

Superseded by #826 (combined PR per reviewer request).