[Yum] deploying and maintaining linux networks howto

[Robert G. Brown]

On Wed, 23 Apr 2003, Carroll, Jim P [Contractor] wrote:

> I've been meaning to do something along these lines for some time now.
> I like the idea; indeed, the general concepts are espoused on
> www.infrastructures.org, but it's nice to see a specific HOWTO document,
> even if it's more specific to a Linux solution.
>
> BTW, is there anyplace one can find a cfengine RPM?

Well, google turns a mdk rpm on rpmfind and elsewhere, but I assume you
found that.  I (we) used to use cfengine some years ago, but then pretty
much stopped.  The problem that it solved was mostly system
inhomogeneity -- dealing with multiple slightly different systems in a
network.  Those same problems can also be solved with common scripting
languages -- perl, python, /bin/sh -- and sysadmins are likely to be
more familiar with those tools.  In our environment we solve them by
also eliminating as much as humanly possible of the heterogeneity that
made such a tool useful.  ALL our systems run RH linux, stable.  ALL our
systems use NIS for core DB's and use the same core DB's.  ALL our
systems install from dhcp/kickstart, and do %post configuration with a
(fairly simple and obvious) shell script, not cfe (which would require
one to learn yasl to operate).  We use yum to maintain software from an
rpm base, and rpm's have their own %post to manage install and deinstall
automagically.  We use syslog-ng to watch all the systems on a
centralized system and have simple watchdogs running there to trigger
warnings of impending disaster.  Finally, there are scripts to run root
commands on whole blocks of the network at once.

So system maintenance of the sort cfengine automates just never occurs
in our network, at least not under ordinary circumstances.  With around
500 CPUs being maintained by just two humans (and only around half of
those in a relatively controlled "cluster" environment), it can't be
permitted to.  Seth can reinstall any system, remotely, with a couple of
commands, to whatever the "clean" and current OS/Distro image is.  yum
automagically updates any installed package, including its config files,
to department standard.

I >>like<< cfe anyway, and think it can be useful (and am glad that it
is in the new HOWTO), but if you view the network as a giant freeform
democracy, or better as a memetic superentity, it appears to "think"
otherwise, as evidenced by the fact that cfengine isn't in major
distributions anymore and google (the entity's "memory" function)
struggles to find an rpm, and some of the cfengine.org mirror sites seem
to be or have dead links, and yes, it doesn't even have an rpm.  Not
forgotten, but somehow only a memory in operation on a handful of
"neural nodes" in this extended linux neural network we call the
Internet.

   rgb

> 
> jc
> 
> 
> > -----Original Message-----
> > From: Zouhir Hafidi [mailto:Zouhir.Hafidi at agat.univ-lille1.fr]
> > Sent: Wednesday, April 23, 2003 5:30 AM
> > To: kickstart-list at redhat.com
> > Cc: yum at lists.dulug.duke.edu
> > Subject: [Yum] deploying and maintaining linux networks howto
> > 
> > 
> > Hi everybody,
> > 
> > for those who want to autoinstall with kickstart, update
> > with yum, and maintain with cfengine you can take a look 
> > at this howto (first draft): 
> > 
> > http://www-gat.univ-lille1.fr/~hafidi/deploy_and_maintain_howto/
> > 
> > it is a "step by step" document to:
> > - create an installation tree
> > - merge updates with a simple python script
> > - install with kickstart
> > - update with yum
> > - maintain with cfengine
> > 
> > any feedback is welcome,
> > 
> > ZH
> > ----------------
> > Zouhir HAFIDI    
> > USTL, U.F.R. de Mathematiques, Bat. M2
> > F-59655 Villeneuve d'Ascq CEDEX, FRANCE
> > tel (+33) 3.20.43.45.15	fax (+33) 3.20.43.43.02
> > 
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> > 
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-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu