[arch-general] Reboot - Versioned Kernel Installs

[C Anthony Risinger]

On Thu, Jun 9, 2011 at 5:36 PM, C Anthony Risinger <anthony at xtfx.me> wrote:
> 2011/6/9 Joe(theWordy)Philbrook <jtwdyp at ttlc.net>:
>>
>> This is the kind of thing that caused me to become a ‘multi-Linux distribution’,
>> ‘multi-boot’ kind of guy in the first place. When an upgrade «or my own
>> dumb mistakes» break my system I like being able to simply reboot something
>> else and finish anything I'm working on before I spend hours, or days, or
>> even weeks just trying to figure out what broke...
>>
>> It's not likely that anything other than a hardware failure will shut down
>> Arch AND Ubuntu AND PCLinuxOS AND OpenSuSE all at the same time... And for
>> that I still have a laptop...
>>
>> But it would sure be nice to be able to keep using my favorite distro with
>> a fallback kernel instead of having to boot one of the others. But I do
>> have to agree that more than one fully functional old kernel is a bad
>> idea. Though I don't have much trouble manually deleting the really old ones
>> from Ubuntu's /boot dir...
>
> what if we (optionally) stored the original images _inside_ the new
> one?  the new/bad kernel would boot, and via some bootloader entry eg.
> kernel param the new initcpio script would kexec the old kernel, with
> another (different) kernel param ... when the old kernel booted it
> would load the exact same initramfs image, except it would use an
> alternate tree, ie. instead of /init it would chroot to /previous and
> run /previous/init ...
>
> you could store as many of these "old" images as you liked, but it
> would look like one -- i don't see any technical problems off-hand at
> least, and i *think* it would only require minor changes to
> mkinitcpio, and would be unobtrusive to other tools.
>
> does this sound genius or completely insane?  some insanely genius guy
> once said they are only separated by a fine line ...

oops, forgot to mention one caveat -- if the new kernel was totally
borked and didn't boot at *all* and couldnt even get to the initramfs,
then it wouldn't work ... but i dont think thats ever happened to me
and seems pretty rare.

C Anthony