fix(azure/rhel-ai): harden RHEL AI provisioning on Azure

[rishupk]

Summary

Combines three related Azure RHEL AI fixes into a single PR (per reviewer request). These were discovered and validated during end-to-end testing with Claudio.

Commit 1 — Disk controller type (was #823): RHEL AI gallery images require SCSI but mapt never set it explicitly, letting Azure infer a conflicting default on some VM sizes. Now sets DiskControllerType: "SCSI" in ImageReference and validates against the gallery image's features.

Commit 2 — GPU guardrails (was #825): Spot allocation could pick non-GPU VMs for RHEL AI, causing vllm to fail silently. Adds isGPUCapableSize() validation (ND/NC-series only) and defaults GPUs=1 when unset.

Commit 3 — NVMe filter + credential handling (was #824): L-series VMs bypassed the local storage filter via NVMe capability. Also fixes credential resolution (ARM_* → AZURE_* mapping) for code paths that run before provider.Init().

Supersedes #823, #824, #825.

Co-Authored-By: Claude Opus 4.6 noreply@anthropic.com
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 32 minutes and 46 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: e9849919-8763-42f7-9088-15ee5b8e3bda

📥 Commits

Reviewing files that changed from the base of the PR and between 25a9684 and 92e39f9.

📒 Files selected for processing (10)

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

📝 Walkthrough

Walkthrough

This PR extends the Azure provider with GPU-capable RHEL AI instance selection and disk controller type support. It adds environment credential handling utilities, updates compute request filtering with GPU and NVMe awareness, validates GPU-capable sizes in the RHEL AI action, integrates disk controller type resolution in allocation, and configures disk controllers during VM creation.

Changes

GPU and Disk Controller Type Support

Layer / File(s)	Summary
Azure Environment & Subscription Handling pkg/provider/azure/data/util.go	ensureAzureEnvs() copies ARM_* variables into unset AZURE_* variables; SubscriptionID() exported helper prefers AZURE_SUBSCRIPTION_ID with ARM_SUBSCRIPTION_ID fallback; splitDiskControllerTypes() parses comma-separated disk controller strings. getCredentials() and getGraphClientFactory() updated to call ensureAzureEnvs().
Image Reference & Disk Controller Type Schema pkg/provider/azure/data/imageref.go	ImageReference struct extended with SharedImageID field for Private Shared images and DiskControllerType field for disk controller specification.
Image Metadata & Disk Controller Queries pkg/provider/azure/data/images.go	New GetSharedImageDiskControllerTypes() queries shared gallery image definitions for supported disk controller types via ARM ID parsing. IsImageOffered, GetSharedImage, and SkuG2Support updated to use ensureAzureEnvs() and SubscriptionID() for subscription ID resolution. os import removed.
Compute Request Filtering & GPU-Aware SKU Selection pkg/provider/azure/data/compute-request.go, compute-request_test.go	Replaces FilterComputeSizesByLocation with FilterComputeSizesByDiskControllerType for disk-controller matching. FilterNoLocalStorageSizes refactored to filter by NVMe disk size with warning logs for dropped and unknown sizes. Internal virtualMachine struct extended with GPU count, NVMe disk size, and disk controller types fields. getAzureVMSKUs refactored to use environment handling and client-factory pagination. filterCPUsAndMemory adds GPU-aware filtering. Comprehensive test coverage includes NVMe classification, disk controller parsing, SKU filtering, and GPU+NVMe edge cases.
VM Size Offering by Location pkg/provider/azure/data/vmsize.go	FilterVMSizeOfferedByLocation uses ensureAzureEnvs() and SubscriptionID() for subscription ID. os import removed.
RHEL AI GPU Instance Validation & Provisioning pkg/provider/azure/action/rhel-ai/rhelai.go, rhelai_test.go	New isGPUCapableSize() classifies ND/NC-series as GPU-capable. Enhanced Create() validates inputs, shallow-copies ComputeRequest, filters NVMe sizes, defaults GPUs to 1, enforces GPU-capable sizing, and hard-sets DiskControllerType: "SCSI". Updated error handling distinguishes GPU-quota/incompatibility failures. Test covers GPU size classification.
Allocation Module — Image Reference Resolution & Filtering pkg/provider/azure/modules/allocation/allocation.go	New resolveImageRef() enriches shared-gallery images by querying supported disk controller types, setting DiskControllerType when exactly one type is returned and caller unspecified. Allocation() derives effective image reference, filters compute sizes by disk-controller compatibility in both spot and non-spot paths, and returns resolved image reference.
Virtual Machine Creation with Disk Controller Type pkg/provider/azure/modules/virtual-machine/virtual-machine.go	Create() sets VM StorageProfile.ManagedDisk.DiskControllerType based on image's DiskControllerType. isSelfOwned() uses data.SubscriptionID() instead of direct environment read. New diskControllerTypePtr() helper converts empty string to nil, otherwise pulumi.StringPtr(). os import removed.

🎯 3 (Moderate) | ⏱️ ~25 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 43.33% 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 accurately summarizes the main change: hardening RHEL AI provisioning on Azure through multiple fixes (disk controller, GPU guardrails, NVMe/credential handling).
Description check	✅ Passed	The description clearly explains all three related fixes being combined, their purpose, and which issues they supersede, all relevant to the changeset.
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/compute-request.go`:
- Line 39: The function FilterComputeSizesByDiskControllerType dereferences the
pointer parameter location (used in strings.EqualFold(*loc, *location)) without
checking for nil; add a nil-check at the start of
FilterComputeSizesByDiskControllerType that returns a clear error if location ==
nil (or handle nil explicitly per caller expectations), so the subsequent loop
comparing *loc and *location is safe; update any error message to reference the
function name and the location parameter for clarity.

🪄 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: 6e77b6cc-cb5b-4ca8-af65-5e3214d423fc

📥 Commits

Reviewing files that changed from the base of the PR and between 7c5d50d and 25a9684.

📒 Files selected for processing (10)

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