install: Add `--karg-delete` by hone · Pull Request #2105 · bootc-dev/bootc

hone · 2026-03-29T05:06:27Z

Following up from the contribfest session. This adds --karg-delete to install.

In some relatively rare use cases, one might want to remove a kernel argument shipped in the container image.

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This pull request introduces the ability to remove kernel arguments during installation via a new --karg-delete CLI option and a corresponding karg-deletes field in the installation configuration. The implementation includes logic to process these deletions before applying new arguments, a helper function for precise or key-based removal, and comprehensive unit and integration tests to verify the functionality. I have no feedback to provide.

hone · 2026-03-29T05:11:27Z

I wasn't sure about a few things when implementing this.

What is the preferred order of precedence for how --karg and --karg-delete interface. kargs can come from root_setup, install_config, and the CLI. In order to let you delete kargs and allow you to replace it with a CLI flag, I deleted the kargs before applying the CLI flags.
Do all install CLI flags also get applied to config? I modeled a configuration option based off of kargs.
I wasn't sure which tests to add, so I added some unit tests, integration, and tmt tests.

This adds `--karg-delete` to install. In some relatively rare use cases, one might want to remove a kernel argument shipped in the container image. Fixes: bootc-dev#1229 Signed-off-by: Terence Lee <hone02@gmail.com>

Signed-off-by: Terence Lee <hone02@gmail.com>

hone · 2026-03-31T23:34:09Z

For my tmt test, I used fixme_skip_if_composefs: true. It didn't look like the composefs boot supported the CLI flags.

…plemented for composefs Signed-off-by: Terence Lee <hone02@gmail.com>

henrywang · 2026-04-02T04:45:34Z

Hi @hone, please skip Packit s390x rpm build issue. The build is successful, but status can't be updated in PR. I already ask for help in Packit channel.

Johan-Liebert1 · 2026-04-02T05:33:06Z

tmt/tests/booted/test-install-karg-delete.nu

+#   summary: Test bootc install --karg-delete
+#   duration: 30m
+# extra:
+#   fixme_skip_if_composefs: true


This should work for composefs backend as well since the config gathering in the install path is pretty much the same for ostree and composefs. Were you getting some sort of error when testing this for composefs backend?

Just that if you use --to-filesystem you need to setup the entire boot partition table, so you can't use --bootloader none.

I was looking through setup_composefs_boot and it didn't look like it handled the CLI karg/-delete args I was working on in install_container.

We can only do this with type1 BLS though to be clear with composefs, not UKIs. We have to error out on any local karg manipulations there.

cgwalters

Thanks! Looks sane offhand

cgwalters · 2026-04-03T15:29:22Z

crates/lib/src/install.rs

+    if let Some(install_config_karg_deletes) = install_config_karg_deletes {
+        for karg_delete in install_config_karg_deletes {
+            karg_deletes.push(karg_delete);
+        }
+    }
+    if let Some(deletes) = state.config_opts.karg_delete.as_ref() {
+        for karg_delete in deletes {
+            karg_deletes.push(karg_delete);
+        }
+    }


Minor style nit I think this could all be one combinator chain via .chain().flatten().collect()

cgwalters · 2026-04-03T15:30:04Z

crates/lib/src/install.rs


+pub(crate) fn delete_kargs(existing: &mut Cmdline, deletes: &Vec<&str>) {
+    for delete in deletes {
+        if let Some(param) = utf8::Parameter::parse(&delete) {


Hmm when would we get None from parsing here? Just when it's an empty string right? We should probably have filtered those out or errored if I'm right

Empty strings or strings with only whitespace will return None, anything else should successful parse.

cgwalters · 2026-04-03T21:11:44Z

What is the preferred order of precedence for how --karg and --karg-delete interface. kargs can come from root_setup, install_config, and the CLI. In order to let you delete kargs and allow you to replace it with a CLI flag, I deleted the kargs before applying the CLI flags.

I think as implemented the CLI should always win, right? We should probably error with --karg=foo and --karg-delete=foo though.

Do all install CLI flags also get applied to config? I modeled a configuration option based off of kargs.

I'm not totally parsing this - it's more that the CLI and config all fold into the bootloader ocnfig.

I wasn't sure which tests to add, so I added some unit tests, integration, and tmt tests.

It's confusing, what you did is fine, but a lot of the install tests were already duplicated. It's a complex problem though, I'll write up a separate tracker issue for this.

github-actions bot added the area/install Issues related to `bootc install` label Mar 29, 2026

bootc-bot bot requested a review from jmarrero March 29, 2026 05:06

gemini-code-assist bot reviewed Mar 29, 2026

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hone force-pushed the install-karg-delete branch 2 times, most recently from 22c5fa8 to 8cb46ce Compare March 29, 2026 09:42

hone added 4 commits March 31, 2026 03:21

install: Add --karg-delete

be58444

This adds `--karg-delete` to install. In some relatively rare use cases, one might want to remove a kernel argument shipped in the container image. Fixes: bootc-dev#1229 Signed-off-by: Terence Lee <hone02@gmail.com>

fix: support verity on fs for composefs tests

d44cb30

Signed-off-by: Terence Lee <hone02@gmail.com>

fix: remove bootloader from test when using to-filesystem

417551c

Signed-off-by: Terence Lee <hone02@gmail.com>

set bootloader to none

ddbbb3f

Signed-off-by: Terence Lee <hone02@gmail.com>

hone force-pushed the install-karg-delete branch from ccccf8a to ddbbb3f Compare March 31, 2026 08:21

github-actions bot added the area/documentation Updates to the documentation label Mar 31, 2026

ignore composefs tmt for now since --karg and --karg-delete aren't im…

87f13a7

…plemented for composefs Signed-off-by: Terence Lee <hone02@gmail.com>

hone force-pushed the install-karg-delete branch from 35c3e5d to 87f13a7 Compare April 1, 2026 13:41

Johan-Liebert1 reviewed Apr 2, 2026

View reviewed changes

cgwalters approved these changes Apr 3, 2026

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cgwalters merged commit fa95cfd into bootc-dev:main Apr 3, 2026
61 of 65 checks passed

hone deleted the install-karg-delete branch April 3, 2026 19:54

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install: Add `--karg-delete`#2105

install: Add `--karg-delete`#2105
cgwalters merged 5 commits intobootc-dev:mainfrom
hone:install-karg-delete

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