[arch-general] Keep older kernel intact while upgrading to new kernel

[C Anthony Risinger]

On Jul 17, 2010, at 11:42 AM, Loui Chang <louipc.ist at gmail.com> wrote:

> On Sat 17 Jul 2010 11:06 -0500, Victor Lowther wrote:
>> On Sat, 2010-07-17 at 10:42 -0500, Thomas Dziedzic wrote:
>>> On Sat, Jul 17, 2010 at 10:38 AM, Victor Lowther
>>> <victor.lowther at gmail.com> wrote:
>>>> On Sat, 2010-07-17 at 23:10 +0800, Ng Oon-Ee wrote:
>>>>> On Sat, 2010-07-17 at 09:17 -0500, Victor Lowther wrote:
>>>>>> On Sat, 2010-07-17 at 18:05 +0400, Евгений Борисов
>>>>>>  wrote:
>>>>>>> I think it's a bad idea, because the directory /lib/modules/
>>>>>>> $oldVersion$
>>>>>>> will be removed when the package is upgraded kernel. Trivial
>>>>>>> solution not
>>>>>>> exists.
>>>>>>
>>>>>> My solution is to hand-roll my own kernels and initramfs'es after
>>>>>> removing the kernel and mkinitcpio packages.  The way Arch
>>>>>> handles its
>>>>>> kernel packages is a weak point -- Fedora and Ubuntu get this
>>>>>> bit right.
>>>>>
>>>>> Yeah, why not keep all previous kernels and headers around. We
>>>>> could
>>>>> automatically extend menu.lst too!
>>>>
>>>> It wold be better than updating to a new kernel, rebooting, and
>>>> having
>>>> to boot to a LiveCD to get back into your system because the new
>>>> kernel
>>>> fscked things up.
>>>>
>>>> Keeping versioned header files also comes in handy -- I take it
>>>> you heve
>>>> never tried any sort of testing with out-of-tree drivers or kernel
>>>> subsystems? Using DKMS on arch is a pointless waste of time because
>>>> older kernel headers are not kept around.
>>>>
>>>>> I'm not sure what you like about Fedora and Ubuntu handling of
>>>>> kernels,
>>>>> but I found it very annoying to have all that stuff hanging
>>>>> around.
>>>>> Would be worse with rolling release I'm sure.
>>>>
>>>> I like knowing that I will not have to hunt for a LiveCD or a
>>>> rescue USB
>>>> drive if a kernel update renders the system unbootable.
>>>>
>>>>
>>>
>>> This wouldn't be a problem if you have a backup kernel :)
>>
>> Oh, I do.  I would just prefer to work with the package management
>> framework, not work around it.
>
> I think this is something that hooks could do. It's a feature that's
> in
> brainstorming. Maybe you could help implement it.
>
> http://wiki.archlinux.org/index.php/User:Allan/Pacman_Hooks

As a heads up, this (kernel rollbacks) is a planned feature of the
mkinitcpio-btrfs hook in AUR.  It will be implemented in one or more
of about three ways:

https://bbs.archlinux.org/viewtopic.php?pid=778395#p778395

and will be in the next major release; hopefully within 3 weeks or
so.  I'm less than 2 weeks from moving my family to a new state so
free development has taken a back seat for a short while.

You must be using btrfs for / of course.

C Anthony