Customized images

[Michael Stone]

On Tue, Jan 06, 2009 at 03:52:44PM -0500, Erik Garrison wrote:
>On Tue, Jan 06, 2009 at 03:23:32PM -0500, Michael Stone wrote:
>> 
>> On Mon, Jan 05, 2009 at 02:27:45PM -0500, Carlos Dario Isaza Zamudio wrote:
>> >I have a fully customized XO and i need to take an image from it to be
>> >installed on several computers inside the project. The thing is i need it to
>> >be separated from the activity pack, like the ones you use to update via
>> >USB.
>> 
>> Hi Carlos,
>> 
>> Thanks for the great questions.
>> 
>> >Questions
>> >1) When i take the image from this one and install it into another, will i
>> >have two computers wchi are exactly the same?
>> 
>> No. Each XO contains unique "manufacturing data", stored in a
>> non-volatile memory which is separate from the main (1GB) non-volatile
>> memory.
>> 
>> Moreover, when you boot an XO, it runs some software which "dirties" the
>> filesystem. You'd want to "clean" the filesystem by undoing some of
>> these edits before you clone the image onto lots of other machines.
>
>Dirty might be too general a word.  Specifically there are a number of
>changes made to system files during the first boot of the machine
>which you might not want to copy between machines.  (SSH keys, for
>instance, are generated once at first boot on every XO.  Also,
>hardware-dependent information from the firmware is cached on the NAND
>after first boot.)
>
>We haven't worked on figuring out what pieces of the system are touched,
>so, as Michael notes, copying the machines can have unintended side
>effects.  It seems that nearly everyone who tries to distribute images
>by cloning runs into some oddities.  That said, it also seems that this
>method of customization is the most appealing and straightforward.  It
>has come up several times recently and I think the time has come to
>properly evaluate it.

Perhaps someone here could be tempted into writing a "clean-up" script
like we discussed the last time this came up?

Michael