[Yum] A few simple questions

[Jason L Tibbitts III]

I'm getting yum going and so far it's keeping a hundred or so machines
updated without any problems at all.  I even have a nice setup where I
can stage updates to test machines before I roll them out to everyone.
But I have a few questions:

---

I've seen folks structure their stock RPM repositories as "base" and
"updates".  Is there some special reason to do it this way instead of
keeping "base" updated constantly?  I install new machines from the
same repository and I certainly want them to get the proper packages
at install time rather than having to install them and then update
them.

---

What's the best way to maintain a set of "default packages" that can
change over time?  Occasionally I need to add a package to the default
set, and when I do this I need all of the machines on the network to
install it automatically.  I know I can set up yumgroups.xml and do a
"yum groupinstall blah", but that just installs what's in that group
at that time.  If I add a package to the group I don't think the
regular nightly update will grab it.

So far I see two options: modify /etc/cron.daily/yum to do the
groupinstall every night, or make a package that has nothing but
dependencies and install it.  Then when I add a package I can update
this RPM and the nightly update will take care of everything during
dependency resolution.  Is there a simpler way?

---

Has anyone tried keeping laptops updated?  The problem I see is that
they won't always be on the network, but I don't know how badly things
will blow up when that happens.  I also can't do IP restrictions on
the server and I'm not sure if I can do any kind of secure or
authenticated HTTP to get the packages.

Thanks for yum and any info you might provide,
-- 
  Jason L Tibbitts III - tibbs at math.uh.edu - 713/743-3486 - 660PGH - 94 PC800
       System Manager:  University of Houston Department of Mathematics