keeping multiple debian machines in sync

[Steve Hsieh <steveh@eecs.umich.edu>]

Having used debian for quite awhile now, I've really come to appreciate
the package system and it works great on an individual machine basis.  
But as soon as you have to start keeping many debian systems in sync with
each other, it starts to get time consuming using dselect.

How have others tackled this problem of keeping 10 or more debian linux
machines synced together?  I assume you don't go about running dselect on
each machine.  One alternative I can think of is to use dpkg
--get-selection to get the list of installed packages on a master machine,
and then use dpkg --set-selection on the rest of the machines to set what
is selected to be installed, and then to run dpkg over there.  Still in
that case, I still have to babysit each install process and answer the
same questions in the post-install scripts as I did on the master machine.

The other alternative seems to be using rdist or some similar program and
rdisting /usr and selected parts of /var to the other machines.  But in
that case, I break the package lists on the other machines since the other
machines will no longer know the correct list of packages already
installed, and it is conceivable that someone might want to add one or two
packages not in the "standard" distribution in which case it might fail.

Ideas?

Thanks.