OCPBUGS-43501: Handle kargs.json correctly in minimal ISO by zaneb · Pull Request #618 · openshift/assisted-image-service

zaneb · 2025-12-10T20:00:46Z

Description

When editing the bootloader files in the minimal ISO, update kargs.json so that it maintains the correct default args, embed area offsets, and embed area sizes. This allows the kernel arguments in the ISO to be manipulated by the user with coreos-installer commands.

How was this code tested?

Generated a minimal ISO using this code and verified that coreos-installer can see and edit the kargs.

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/cc @carbonin

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Title and description added to both, commit and PR
Relevant issues have been associated
Reviewers have been listed
This change does not require a documentation update (docstring, docs, README, etc)
Does this change include unit tests (note that code changes require unit tests)

openshift-ci-robot · 2025-12-10T20:00:48Z

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openshift-ci-robot · 2025-12-10T20:00:54Z

@zaneb: This pull request references Jira Issue OCPBUGS-43501, which is invalid:

expected the bug to target either version "4.21." or "openshift-4.21.", but it targets "4.20.z" instead

Comment /jira refresh to re-evaluate validity if changes to the Jira bug are made, or edit the title of this pull request to link to a different bug.

The bug has been updated to refer to the pull request using the external bug tracker.

Details

In response to this:

Description

When editing the bootloader files in the minimal ISO, update kargs.json so that it maintains the correct default args, embed area offsets, and embed area sizes. This allows the kernel arguments in the ISO to be manipulated by the user with coreos-installer commands.

How was this code tested?

Assignees

/cc @carbonin

Links

Checklist

Title and description added to both, commit and PR

Relevant issues have been associated

Reviewers have been listed

This change does not require a documentation update (docstring, docs, README, etc)

Does this change include unit tests (note that code changes require unit tests)

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openshift-ci · 2025-12-10T20:02:07Z

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: zaneb
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zaneb · 2025-12-10T20:02:22Z

/jira refresh

openshift-ci-robot · 2025-12-10T20:02:30Z

@zaneb: This pull request references Jira Issue OCPBUGS-43501, which is valid. The bug has been moved to the POST state.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target version (4.21.0) matches configured target version for branch (4.21.0)
bug is in the state ASSIGNED, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @mhanss

Details

In response to this:

/jira refresh

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

codecov · 2025-12-10T22:45:47Z

Codecov Report

❌ Patch coverage is 74.54545% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.51%. Comparing base (5038341) to head (b139cee).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/isoeditor/rhcos.go	74.54%	13 Missing and 15 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #618      +/-   ##
==========================================
+ Coverage   59.02%   60.51%   +1.49%     
==========================================
  Files          27       27              
  Lines        1674     1755      +81     
==========================================
+ Hits          988     1062      +74     
- Misses        524      527       +3     
- Partials      162      166       +4

Files with missing lines	Coverage Δ
pkg/isoeditor/rhcos.go	`61.45% <74.54%> (+21.81%)`	⬆️

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

zaneb · 2025-12-11T03:10:13Z

/retitle OCPBUGS-43501,OCPBUGS-64929: Handle kargs.json correctly in minimal ISO

openshift-ci-robot · 2025-12-11T03:10:27Z

@zaneb: This pull request references Jira Issue OCPBUGS-43501, which is valid.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target version (4.21.0) matches configured target version for branch (4.21.0)
bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @mhanss

The bug has been updated to refer to the pull request using the external bug tracker.

This pull request references Jira Issue OCPBUGS-64929, which is invalid:

expected the bug to target the "4.21.0" version, but no target version was set

Comment /jira refresh to re-evaluate validity if changes to the Jira bug are made, or edit the title of this pull request to link to a different bug.

The bug has been updated to refer to the pull request using the external bug tracker.

Details

In response to this:

Description

When editing the bootloader files in the minimal ISO, update kargs.json so that it maintains the correct default args, embed area offsets, and embed area sizes. This allows the kernel arguments in the ISO to be manipulated by the user with coreos-installer commands.

How was this code tested?

Assignees

/cc @carbonin

Links

Checklist

Title and description added to both, commit and PR

Relevant issues have been associated

Reviewers have been listed

This change does not require a documentation update (docstring, docs, README, etc)

Does this change include unit tests (note that code changes require unit tests)

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

openshift-ci-robot · 2025-12-11T03:14:09Z

@zaneb: This pull request references Jira Issue OCPBUGS-43501, which is valid.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target version (4.21.0) matches configured target version for branch (4.21.0)
bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @mhanss

This pull request references Jira Issue OCPBUGS-64929, which is invalid:

expected the bug to target the "4.21.0" version, but no target version was set

Comment /jira refresh to re-evaluate validity if changes to the Jira bug are made, or edit the title of this pull request to link to a different bug.

Details

In response to this:

Description

When editing the bootloader files in the minimal ISO, update kargs.json so that it maintains the correct default args, embed area offsets, and embed area sizes. This allows the kernel arguments in the ISO to be manipulated by the user with coreos-installer commands.

Also, when extracting ISO files, rename them to 8.3 format so that when they are repacked into an ISO they will have ISO 9660 Level 1 compatible filenames, which is necessary for coreos-installer to make use of them. A proper fix for this is diskfs/go-diskfs#315, but for now we are copying the fix already used in the installer so that it applies to all consumers of the library.

How was this code tested?

Generated a minimal ISO using this code and verified that coreos-installer can see and edit the kargs.

Assignees

/cc @carbonin

Links

Checklist

Title and description added to both, commit and PR

Relevant issues have been associated

Reviewers have been listed

This change does not require a documentation update (docstring, docs, README, etc)

Does this change include unit tests (note that code changes require unit tests)

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

zaneb · 2025-12-11T03:15:04Z

/jira refresh

openshift-ci-robot · 2025-12-11T03:15:13Z

@zaneb: This pull request references Jira Issue OCPBUGS-43501, which is valid.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target version (4.21.0) matches configured target version for branch (4.21.0)
bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @mhanss

This pull request references Jira Issue OCPBUGS-64929, which is valid. The bug has been moved to the POST state.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target version (4.21.0) matches configured target version for branch (4.21.0)
bug is in the state ASSIGNED, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @mhanss

Details

In response to this:

/jira refresh

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

carbonin

Can we rename some of the functions so it's easier to understand the difference between updateKargs, updateKernelArgs, and updateDefaultKargs?

pkg/isoeditor/isoutil.go

openshift-ci-robot · 2025-12-17T21:42:54Z

@zaneb: This pull request references Jira Issue OCPBUGS-43501, which is invalid:

expected the bug to target either version "4.22." or "openshift-4.22.", but it targets "4.21.0" instead

Comment /jira refresh to re-evaluate validity if changes to the Jira bug are made, or edit the title of this pull request to link to a different bug.

This pull request references Jira Issue OCPBUGS-64929, which is valid.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target version (4.22.0) matches configured target version for branch (4.22.0)
bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @mhanss

Details

In response to this:

Description

When editing the bootloader files in the minimal ISO, update kargs.json so that it maintains the correct default args, embed area offsets, and embed area sizes. This allows the kernel arguments in the ISO to be manipulated by the user with coreos-installer commands.

This PR is based on top of #620, which is a prerequisite for fixing the bug.

How was this code tested?

Generated a minimal ISO using this code and verified that coreos-installer can see and edit the kargs.

Assignees

/cc @carbonin

Links

Checklist

Title and description added to both, commit and PR

Relevant issues have been associated

Reviewers have been listed

This change does not require a documentation update (docstring, docs, README, etc)

Does this change include unit tests (note that code changes require unit tests)

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

zaneb · 2025-12-18T16:59:52Z

/jira refresh

openshift-ci-robot · 2025-12-18T16:59:59Z

@zaneb: This pull request references Jira Issue OCPBUGS-43501, which is valid.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target version (4.22.0) matches configured target version for branch (4.22.0)
bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @mhanss

This pull request references Jira Issue OCPBUGS-64929, which is valid.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target version (4.22.0) matches configured target version for branch (4.22.0)
bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @mhanss

Details

In response to this:

/jira refresh

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

zaneb · 2026-01-28T04:33:04Z

/retitle OCPBUGS-43501: Handle kargs.json correctly in minimal ISO

I will rebase this once #620 merges.

openshift-ci-robot · 2026-01-28T04:33:13Z

@zaneb: This pull request references Jira Issue OCPBUGS-43501, which is valid.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target version (4.22.0) matches configured target version for branch (4.22.0)
bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @mhanss

The bug has been updated to refer to the pull request using the external bug tracker.

Details

In response to this:

Description

When editing the bootloader files in the minimal ISO, update kargs.json so that it maintains the correct default args, embed area offsets, and embed area sizes. This allows the kernel arguments in the ISO to be manipulated by the user with coreos-installer commands.

This PR is based on top of #620, which is a prerequisite for fixing the bug.

How was this code tested?

Generated a minimal ISO using this code and verified that coreos-installer can see and edit the kargs.

Assignees

/cc @carbonin

Links

Checklist

Title and description added to both, commit and PR

Relevant issues have been associated

Reviewers have been listed

This change does not require a documentation update (docstring, docs, README, etc)

Does this change include unit tests (note that code changes require unit tests)

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

Quoting is required in grub.cfg, and was added in MGMT-4693. This solves the problem that the '&' character in a URL is considered a word separator by Grub. However, having different kernel args between isolinux.cfg and grub.cfg is likely problematic for coreos-installer when editing kargs. Making them the same length also avoids the need to adjust padding in order to keep the same embed area length in each file (which is required, as kargs.json does not store per-file embed area sizes). isolinux.cfg does not use quoting, so the parameter will be passed to the kernel quoted. The kernel will only strip double quotes, not single quotes. In grub.cfg, using double quotes allows the expansion of variables with '$' and escaping with '\' (both of which are suppressed when using single quotes). '\' is not a valid character in a URL. '$' technically is, but is vanishingly rare. We will prohibit these characters so that we can use the same kargs in both files. Assisted-by: Cursor

Consolidate the duplicated logic for modifying kernel arguments into a single transformKernelArgs() function. This function: - Validates the rootfs URL - Removes the coreos.liveiso parameter - Adds the coreos.live.rootfs_url parameter at a specified position Both fixGrubConfig and fixIsolinuxConfig use this single implementation instead of each having their own inline logic. This eliminates code duplication and makes the transformation logic easier to understand and maintain. Assisted-by: Cursor Assisted-by: Claude Code

Introduce editString() function that uses named capture groups to precisely target content for replacement. The (?P<replace>) syntax makes it explicit what is being replaced in each regex operation. Convert transformKernelArgs, fixGrubConfig and fixIsolinuxConfig to use editString for their transformations. This provides better control over regex substitutions than full-string replacement. Assisted-by: Cursor Assisted-by: Claude Code

Read and update kargs.json metadata that coreos-installer uses to manage kernel arguments in the ISO. When we modify the default kernel arguments (removing coreos.liveiso and adding coreos.live.rootfs_url), update kargs.json to reflect these changes. This ensures coreos-installer can correctly edit kernel arguments after the ISO is created. Assisted-by: Cursor Assisted-by: Claude Code

When modifying kernel arguments in grub.cfg or isolinux.cfg, track how these changes shift the position of the kargs embed area. Update the offsets in kargs.json so that coreos-installer can find the correct embed area after our modifications. Without this fix, adding initramfs images in isolinux.cfg can shift the kargs embed area, causing coreos-installer kargs edits to fail or corrupt the file. Assisted-by: Cursor Assisted-by: Claude Code

zaneb · 2026-02-04T21:01:41Z

ofcir setup failed
/retest-required

openshift-ci · 2026-02-04T22:47:38Z

@zaneb: all tests passed!

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openshift-ci bot requested a review from carbonin December 10, 2025 20:00

openshift-ci bot added the size/L Denotes a PR that changes 100-499 lines, ignoring generated files. label Dec 10, 2025

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openshift-ci bot requested a review from mhanss December 10, 2025 20:02

zaneb force-pushed the minimal-kargs branch from 3fc9064 to 3d2f217 Compare December 10, 2025 22:34

zaneb force-pushed the minimal-kargs branch from 3d2f217 to fd47585 Compare December 11, 2025 03:09

openshift-ci bot added size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. and removed size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Dec 11, 2025

openshift-ci bot changed the title ~~OCPBUGS-43501: Handle kargs.json correctly in minimal ISO~~ OCPBUGS-43501,OCPBUGS-64929: Handle kargs.json correctly in minimal ISO Dec 11, 2025

openshift-ci-robot added jira/invalid-bug Indicates that a referenced Jira bug is invalid for the branch this PR is targeting. and removed jira/valid-bug Indicates that a referenced Jira bug is valid for the branch this PR is targeting. labels Dec 11, 2025

openshift-ci-robot added the jira/valid-bug Indicates that a referenced Jira bug is valid for the branch this PR is targeting. label Dec 11, 2025

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zaneb force-pushed the minimal-kargs branch 2 times, most recently from ef112b8 to ab25b69 Compare December 11, 2025 03:55

carbonin reviewed Dec 11, 2025

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pkg/isoeditor/isoutil.go Outdated Show resolved Hide resolved

zaneb force-pushed the minimal-kargs branch from ab25b69 to ea20b7d Compare December 17, 2025 19:07

openshift-ci-robot added jira/invalid-bug Indicates that a referenced Jira bug is invalid for the branch this PR is targeting. and removed jira/valid-bug Indicates that a referenced Jira bug is valid for the branch this PR is targeting. labels Dec 17, 2025

openshift-ci-robot added jira/valid-bug Indicates that a referenced Jira bug is valid for the branch this PR is targeting. and removed jira/invalid-bug Indicates that a referenced Jira bug is invalid for the branch this PR is targeting. labels Dec 18, 2025

openshift-merge-robot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Jan 27, 2026

openshift-ci bot changed the title ~~OCPBUGS-43501,OCPBUGS-64929: Handle kargs.json correctly in minimal ISO~~ OCPBUGS-43501: Handle kargs.json correctly in minimal ISO Jan 28, 2026

openshift-ci-robot mentioned this pull request Jan 30, 2026

OCPBUGS-64929: Update to diskfs master with ISO 9660 extension fix #620

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zaneb added 5 commits February 2, 2026 11:13

zaneb force-pushed the minimal-kargs branch from ea20b7d to b139cee Compare February 1, 2026 22:15

openshift-merge-robot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Feb 1, 2026

openshift-ci bot added size/L Denotes a PR that changes 100-499 lines, ignoring generated files. and removed size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. labels Feb 1, 2026

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