Re: [Devil-linux-develop] remote update

[Heiko Z. <he...@zu...>]

Friedrich Lobenstock wrote:

> Bruce Smith wrote on 09.02.2004 01:28 MET:
> 
>>>> What about automatically updating the stick from CD?  Burn the new 
>>>> image
>>>> on CD, boot from CD, and it copies itself to the USB stick.  It could
>>>> also be used to initially create a bootable stick (blank).
>>>>
>>>> Just a thought, CD drives are a LOT cheaper than big memory sticks.
>>>
>>>
>>> What if it boots of off the USB stick, checks for an "update-CD" 
>>> (just a normal CD, but created from a newer ISO), does an update if 
>>> necessary and then moves one?
>>
>>
>>
>> Sure, if that can be done.  I was worried about problems updating a
>> running system (replacing libraries in use, etc.), which is why I
>> suggested booting off CD.
> 
> 
> It has to be done in the initrd anyway and you are not changing those 
> libraries when doing the update. And yes this might be a problem of its 
> own, we can not change the initrd anymore. Hmmmmm.....then initrd needs 
> some fixed parts (does not change across stable version) which loads the 
> varibale ones, taking into account to update those if an "update CD" 
> exists. Then the rest of the system is updated. Now this might also be a 
> good idea to include the update script _from_ CD. This way we can 
> provide for a more complicated if we did not think about a specific 
> update problem later and as this script is tamper proof (on CD!) it can 
> check all the signatures against a provided signature file (is that 
> really needed?).

Since all update functions are on the CD anyway (pre_init script), the 
existance of this script would be the only requirement.

This would be the procedure:
1. initrd loads
2. initrd replaces bootcd.iso with bootcd.iso.new (after verifying it)
3. initrd continues as usual
4. pre_init sees the CD version is different to the config version and 
performs an update (interactive part already implemented).

I didn't think to much about the upgrade script yet, but that's a 
separate issue.

Heiko