Re: Grub-question when performing Kernel-upgrade

[Alban Crequy]

Le dimanche 06 février 2005 à 03:58, Ketjes Jette a écrit:
> - At the first boot we would start the new kernel: if I could change
> the default value to 1 before the real kernel is booted (no matter if
> the kernel can boot or not), than my problem is solved.

With the last version of Grub, you can use the "savedefault" feature:

---->8----
default saved
timeout 3

title NewLinux
root (hd0,0)
kernel /boot/vmlinuzNEW ... panic=15
initrd /boot/initrd.img
savedefault 1

title OldLinux
root (hd0,0)
kernel /boot/vmlinuzOLD ...
initrd /boot/initrd.img
savedefault 1
---->8----

"default saved" means that the default stanza is the one specified in
/boot/grub/default.

"savedefault 1" means that Grub will store "1" in /boot/grub/default
just before it boots the kernel.

> - if the kernel boots allright, then I can configure grub so it boots
> my new (and verified) kernel

If your new kernel boots normally, you can use "grub-set-default" to
change the default stanza in /boot/grub/default.

> - if the kernel hangs (hard), I can recycle the power remotely and the
> next time default=1 (= old kernel) and I can correct my problem and
> retry over and over

"panic=15" means that the linux kernel will reboot on panic within 15
seconds. The default value is 0, which means that the linux kernel will
not reboot on panic.

Of couse, if your kernel hangs without panic, you still have to recycle
your power...

> Only: how can I change default right at the boot-menu (without being
> able to type anything at boot-time) ?

savedefault

-- 
Alban