kargs

The kargs module injects kernel arguments into the image. Kernel arguments can be used to define how kernel will interact with the hardware or software.

Instead of modifying & rebuilding the kernel, the module uses /usr/lib/bootc/kargs.d/ to define the kernel arguments. See the link below for how bootc injects kernel arguments:
https://containers.github.io/bootc/building/kernel-arguments.html

Because the kargs are managed by bootc, to use this module, it is required to be have it installed & to be using it for example for updating the image. This means that instead of rpm-ostree update, you need to use bootc update for kargs to get applied on the next boot. Or in case of changing the image, you need to use bootc switch instead of rpm-ostree rebase.

To see which kargs are currently applied, you can issue rpm-ostree kargs command in a local terminal.

To see which kargs are supported in the kernel, you can see this detailed documentation.
Switch the branch accordingly to the kernel version your image is on to get the more accurate version of the documentation.
Take a note it’s possible that some working kargs are not in the documentation.

Example configuration

type: kargs
arch: x86_64, aarch64 # only inject kernel arguments to these specific OS architectures
kargs:
  - console=ttyS0,114800n8
  - mitigations=on
  - systemd.unified_cgroup_hierarchy=0

Configuration options

arch: (optional string)

Defines on which OS architectures are kargs applied. Defaults to all architectures if omitted.

kargs: (required array)

Kargs to inject in the image.