Bug#983486: zipl: allow other packages to provide config snippets

On 24.02.21 23:40, dann frazier wrote:
> Source: s390-tools
> Version: 2.15.1-2
> 
> I'm one of the maintainers of kdump-tools, which has a need to manipulate
> the kernel command line parameters in boot loader configurations.
> Currently zipl provides no way to do this without modifying
> /etc/zipl.conf directly. It would be helpful if there was e.g. an
> /etc/zipl.conf.d/ interface for dropping in additional configuration.
> 
> As an example, GRUB provides an /etc/default/grub.d/ directory, which
> allows us to drop in a file like this:
> 
> $ cat /etc/default/grub.d/kdump-tools.cfg 
> GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=384M-:128M"
> 
> One idea of how to implement this would be to do something similar to
> GRUB and ship a tool (say, update-zlib) that generates a static
> /etc/zlib.conf as directed by a set of shell variables (say
> /etc/default/zlib). It could then process a directory of snippets (say
> /etc/default/zlib.d/*) allowing other packages to tweak/override the
> configuration defined by those variables.
> 
> I realize that while that this design would have an upgrade problem
> for existing users, but perhaps we could provide an opt-in-only
> migration path.
> 

Newer zipls also provide a way to specify BLS entries
https://systemd.io/BOOT_LOADER_SPECIFICATION/
would that help you?

If something like a zipl.conf.d is still considered valueable, maybe
open an issue for the 
upstream project https://github.com/ibm-s390-linux/s390-tools/issues