Freeze SO Linux, it's possible?

[Chris Mohler]

On Fri, Dec 12, 2008 at 7:30 AM, Bart Silverstrim
<bsilver at chrononomicon.com> wrote:
> Chris Mohler wrote:
>> On Thu, Dec 11, 2008 at 4:36 PM, Bart Silverstrim
>> <bsilver at chrononomicon.com> wrote:
>>>
>>> Anthony M. Rasat wrote:
>>>>> As a side note, no, I've never found similar-type software
>>>>> for Linux to "Freeze" it despite looking around.
>>>> What?
>>>> Gimme tar and rc.local, I'll give it to you for free.
>>> That's not *quite* the same as deep freeze...
>>
>> Yeah, that would be rsync and cron (with a healthy side of bash) ;)
>
> Almost, except DF works invisibly and you aren't relying on timed
> snapshots that could become "infected" during a backup so your image is
> contaminated...with DF you only become infected if it happens during a
> thaw cycle.

Was thinking of something like:

Install System into /
Initial "freeze:" Rsync / to a separate partition, and then remount read-only
To "thaw" use rsync to copy from the read-only partition back to /
(and delete any new files on / - see man rsync)

An admin could mount the partition, and use chroot to install/upgrade
software if needed.

cron comes into play if you want to "thaw" every night - wiping out
any changes...

Of course there are some sticky bits here - wiping /home (or not),
skipping /proc, etc. - but unless I am missing something, that should
get the job done.

Chris