OKD-455: Support SCOS image prefix in Nutanix preloadedOSImageName validation

[sarthakpurohit]

Problem

When deploying OKD in IPI mode on Nutanix with preloadedOSImageName configured, the installer always fails with:

FATAL could not retrieve cluster infrastructure variables: ... platform.nutanix.preloadedOSImageName:
Invalid value: "okd-scos": could not validate preloaded rhcos image: could not obtain rhcos image
version from source_uri of preloaded object okd-scos <url>

The root cause is in validatePreloadedImage() which hardcodes /rhcos- as the only recognized image name prefix when extracting the CoreOS version from the preloaded image's source URI. For OKD/SCOS deployments, the Nutanix image URL uses scos- (e.g. scos-10.0.20251103-0-nutanix.x86_64.qcow2), so the validation always fails.

Fix

• Extracted a findImagePrefix helper that searches the source URI for both /rhcos- and /scos- prefixes.
• Replaced the hardcoded magic number 7 (len("/rhcos-")) with len(prefix) so version extraction works for any matched prefix.
• Generalized internal variable names and error messages from "rhcos" to "CoreOS" where applicable.
• Added unit tests for findImagePrefix covering RHCOS, SCOS, unknown prefix, and empty URI cases.

Jira

OKD-455

Upstream Issue

Fixes: okd-project/okd#2356

Summary by CodeRabbit

• Bug Fixes
  • Improved preloaded CoreOS image validation to recognize both RHCOS and SCOS image naming formats.
  • Updated validation errors to use clearer, consistent CoreOS terminology.

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📥 Commits

Reviewing files that changed from the base of the PR and between 280e437 and 7a5a6c4.

📒 Files selected for processing (2)

• pkg/asset/installconfig/nutanix/validation.go
• pkg/asset/installconfig/nutanix/validation_test.go

🚧 Files skipped from review as they are similar to previous changes (2)

• pkg/asset/installconfig/nutanix/validation_test.go
• pkg/asset/installconfig/nutanix/validation.go

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📝 Walkthrough

Walkthrough

Nutanix preloaded image validation now supports RHCOS and SCOS image prefixes. A helper detects the prefix in the source URI. Tests cover supported, unknown, and empty image URIs.

Changes

Nutanix preloaded image validation

Layer / File(s)	Summary
CoreOS image prefix detection and validation pkg/asset/installconfig/nutanix/validation.go, pkg/asset/installconfig/nutanix/validation_test.go	validatePreloadedImage detects /rhcos- and /scos- prefixes through findImagePrefix. Error messages use CoreOS terminology. Tests cover RHCOS, SCOS, unknown, and empty source URIs.

Estimated code review effort: 2 (Simple) | ~10 minutes

Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to 7a5a6

The change expands Nutanix preloaded image validation to support both RHCOS and SCOS URLs, enabling the reported SCOS configuration without an identified merge-blocking risk.

🚥 Pre-merge checks | ✅ 14 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 75.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (14 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the primary change: support for SCOS image prefixes in Nutanix preloaded OS image validation.
Linked Issues check	✅ Passed	The changes address issue #2356 by recognizing both /rhcos- and /scos- image prefixes, extracting the image version correctly, and adding coverage for SCOS URLs.
Out of Scope Changes check	✅ Passed	The implementation and tests remain within scope. The terminology updates support the same validation change and do not introduce unrelated behavior.
Stable And Deterministic Test Names	✅ Passed	PASS — The pull request adds a standard Go table-driven test, not a Ginkgo test. Its t.Run names come from five static string literals: RHCOS/SCOS URL cases, unknown prefix, empty URI, and RHEL 9 st…
Test Structure And Quality	✅ Passed	The changed test is a standard Go testing table test (TestFindImagePrefix with t.Run and testify/assert), not Ginkgo code. It has no cluster operations, resource creation, waits, or cleanup re…
Microshift Test Compatibility	✅ Passed	PASS: The pull request adds a standard Go unit test, TestFindImagePrefix, not a Ginkgo e2e test. The changed files contain no Ginkgo constructs, OpenShift API references, unsupported namespaces, Mic…
Single Node Openshift (Sno) Test Compatibility	✅ Passed	The pull request adds only the standard Go unit test TestFindImagePrefix in pkg/asset/installconfig/nutanix/validation_test.go. It adds no Ginkgo e2e tests such as It, Describe, Context, or …
Topology-Aware Scheduling Compatibility	✅ Passed	PASS: The pull request changes only Nutanix image validation logic and its unit test. The diff adds no deployment manifests, operators, controllers, replicas, affinity, topology spread constraints, no…
Ote Binary Stdout Contract	✅ Passed	The pull request changes only Nutanix validation code and a unit test. The diff adds no fmt.Print*, os.Stdout, os.Write, klog, Ginkgo suite setup, main, init, or TestMain code. The only new logging ca…
Ipv6 And Disconnected Network Test Compatibility	✅ Passed	PASS. The pull request adds a standard Go unit test (TestFindImagePrefix), not a Ginkgo e2e test. The test only compares string values, including URL-shaped inputs; it does not resolve hosts, open c…
No-Weak-Crypto	✅ Passed	PASS: The pull request changes only Nutanix image-prefix detection, version parsing, error text, and tests. The added lines contain no MD5, SHA1, DES, RC4, 3DES, Blowfish, ECB, custom cryptography, or…
Container-Privileges	✅ Passed	PASS: The pull request changes only Go validation code and a Go unit test. The authoritative diff contains no container or Kubernetes manifest and no privileged, hostPID, hostNetwork, hostIPC,…
No-Sensitive-Data-In-Logs	✅ Passed	The pull request does not introduce sensitive-data logging. The changed warning logs only CoreOS version numbers. The validation error still includes the image name and source URI, but the base revisi…

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Actionable comments posted: 2

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Inline comments:
In `@pkg/asset/installconfig/nutanix/validation_test.go`:
- Line 9: Rename the test function Test_findImagePrefix to TestFindImagePrefix
so Go test discovery executes it; leave the test implementation unchanged.

In `@pkg/asset/installconfig/nutanix/validation.go`:
- Line 71: Update both validation error messages in the preloaded OS image
validation paths to report “CoreOS” instead of “rhcos”, including the path using
field.Invalid and the corresponding error at the other reported location.

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📥 Commits

Reviewing files that changed from the base of the PR and between 3fc6df4 and 280e437.

📒 Files selected for processing (2)

• pkg/asset/installconfig/nutanix/validation.go
• pkg/asset/installconfig/nutanix/validation_test.go

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[openshift-ci-robot]

@sarthakpurohit: This pull request references OKD-455 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the bug to target the "5.1.0" version, but no target version was set.

Details

In response to this:

Problem

When deploying OKD in IPI mode on Nutanix with preloadedOSImageName configured, the installer always fails with:

FATAL could not retrieve cluster infrastructure variables: ... platform.nutanix.preloadedOSImageName:
Invalid value: "okd-scos": could not validate preloaded rhcos image: could not obtain rhcos image
version from source_uri of preloaded object okd-scos <url>

The root cause is in validatePreloadedImage() which hardcodes /rhcos- as the only recognized image name prefix when extracting the CoreOS version from the preloaded image's source URI. For OKD/SCOS deployments, the Nutanix image URL uses scos- (e.g. scos-10.0.20251103-0-nutanix.x86_64.qcow2), so the validation always fails.

Fix

• Extracted a findImagePrefix helper that searches the source URI for both /rhcos- and /scos- prefixes.
• Replaced the hardcoded magic number 7 (len("/rhcos-")) with len(prefix) so version extraction works for any matched prefix.
• Generalized internal variable names and error messages from "rhcos" to "CoreOS" where applicable.
• Added unit tests for findImagePrefix covering RHCOS, SCOS, unknown prefix, and empty URI cases.

Jira

OKD-455

Upstream Issue

Fixes: okd-project/okd#2356

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[sarthakpurohit]

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