suggestion: rescue boot extension

[Eric Sandeen]

Richard W.M. Jones wrote:
> On Wed, Jun 02, 2010 at 03:13:21PM -0500, Eric Sandeen wrote:
>> Jon Masters wrote:
>>> On Wed, 2010-06-02 at 13:03 -0700, Roland McGrath wrote:
>>>>> Hm. I can see the use of this, but I can also see issues with how you
>>>>> do updates for it sanely (if at all.)
>>>> Why would you do updates for it?  Your install CD/DVD to use for rescue
>>>> boot doesn't get updated.  I'd think you'd just install a pristine newer
>>>> one verbatim if you had a reason to bother, like deciding to burn a new CD.
>>>> Hence the nice automagic deployment feature would reserve two partitions
>>>> (or whatevers) for the purpose, so you can install the new image on B and
>>>> still have the option to boot A if the new one is bad.
>>> So I'm willing to help out on this (once RHEL stuff calms down a bit).
>>> Do you think it's worth us putting together a wiki feature proposal?
>>>
>>> Jon.
>>>
>>>
>> Is it better to have a separate volume for this, or to just have a sort
>> of rescue initramfs ...?
> 
> Or if you are able to run a little bit of C code[1] and can read files
> from the root partition (as grub can), you can build one on the fly
> using binaries, libraries etc found on the root disk, which is what we
> do in libguestfs.

.... which then solves the "how do I update it?" problem.

(of course if you're trying to recover from an update that borked your
system, I guess you hope you didn't update the rescue recently!)

-Eric

> Rich.
> 
> [1] http://git.annexia.org/?p=febootstrap.git;a=blob;f=febootstrap-supermin-helper.c;hb=HEAD
>