I edited GRUB_CMDLINE_LINUX in /etc/default/grub before I installed the most
recent kernel update. However the grub entry for the new kernel did not
reflect my changes in the updated /boot/grub2/grub.cfg
Digging into this, it appears that the kernel packages run the grubby tool
which appears to be responsible for updating grub.cfg, and it does that,
apparently (not 100% sure) by cloning existing kernel entries; and the
/etc/default/grub file comes from the grub2-tool package, and grubby doesn't
know anything about it.
If I run grub2-mkconfig, it generates something completely different from
the existing grub.cfg. I have not analyzed the differences, but using the
output of grub2-mkconfig seems risky; not sure if subsequent invocations of
grubby will deal with it.
Did anyone use grub2-mkconfig before, to generate a new grub.cfg, and then
subsequently installed kernels new without grubby causing any issues?