Re: [gentoo-user] Managing multiple systems with identical hardware

[Grant <emailgrant@gmail.com>]

>>> I'm about to embark on this (perilous?) journey and I'm wondering if
>>> anyone would make a comment on any of the questions in the last paragraph
>>> below.  This is basically my plan for setting up a bunch of systems
>>> (laptops) in an office which are hardware-identical to my own laptop and
>>> creating a framework to manage them all with a bare minimum of time and
>>> effort.
>>>
>>> Thanks, Grant
>>>
>>>
>>>>>>>>> I see what you desire now - essentially you want to clone
>>>>>>>>> your laptop (or big chunks of it) over to your other
>>>>>>>>> workstations.
>>>>
>>>> I've been working on this and I think I have a good and simple plan.
>>>>
>>>> My laptop roams around with me and is the "master" system.  The office
>>>> router is the "submaster" system.  All of the other office systems are
>>>> "minion" systems.  All of the systems are 100% hardware-identical
>>>> laptops.  All of the minions are 100% software-identical.
>>>>
>>>> I install every package that any system needs on the master and create
>>>> an SSH keypair.  The only config files that change from their state on
>>>> the master are: /etc/conf.d/hostname, /etc/conf.d/net,
>>>> /etc/ssh/sshd_config, /etc/shorewall/*.  I write comments in those
>>>> files which serve as flags for scripted changes.
>>>>
>>>> I write a script that is run from the master to the submaster, or from
>>>> the submaster to a minion.  If it's the former, rsync / is run with
>>>> exceptions (/usr/portage, /usr/local/portage, /var/log, /tmp, /home,
>>>> /root but /root/.ssh/id_rsa_script* is included), my personal user is
>>>> removed, a series of workstation users are created with useradd -m,
>>>> services are added or removed from /etc/runlevels/default, and config
>>>> files are changed according to comment flags.  If it's the latter,
>>>> rsync / is run without exceptions, services are added or removed from
>>>> /etc/runlevels/default, and config files are changed according to
>>>> comment flags.
>>>>
>>>> All user info on the submaster and minions would be effectively reset
>>>> whenever the script is run and that's fine.  Root logins would have to
>>>> be allowed on the submaster and minions but only with the SSH key.
>>>> There are probably more paths to exclude when rsyncing master to
>>>> submaster.
>>>>
>>>> That's it.  No matter how numerous the minions become, this should
>>>> allow me to keep everything running by administrating only my own
>>>> system, pushing that to the submaster, and having the submaster push to
>>>> the minions.  I've been going over the nitty-gritty and everything
>>>> looks good.
>>>>
>>>> What do you think?  Is there anything inherently wrong with rsyncing /
>>>> onto a running system?  If there are little or no changes to make,
>>>> about how much data would actually be transferred?  Is there a better
>>>> tool for this than rsync?  I know Funtoo uses git for syncing with
>>>> their portage tree.
>>>>
>>>> - Grant
>>>
> I'm also somewhat skeptical of rsyncing binaries and libraries on a running
> system - it seems needlessly dangerous, particularly for things that have
> complex deps.
>
> A mixed alternative to this would be:
>
> use rsync to manage distributing the system-wide configuration files for all
> relevant packages (similar to what you're doing at the moment).  This could
> include just the /etc directory (and/or other system-wide config directories)
> leaving the user files untouched
>
> instead of trying to rsync any binaries or libraries, use the master to build
> a binary package ("--buildpkg") of whatever software is to be installed, with
> the package directory shared over NFS or similar.  Then, on the slaves, set
> emerge default opts to "--usepkg" or "--usepkgonly" with a cron job, leaving
> the actual updating of applications on the slave systems to portage.

I may end up using portage instead of rsync but I think I'd like to
try rsync first.  Am I setting myself up for failure?

- Grant