Re: Compute Farm
On Tue, 10 Feb 1998, Tim Sailer wrote:
> The powers-that-be around here have almost decided to scrap Slowaris
> x86 for the 200 machine PPro compouter farm, and go with Linux... I
> need to convince them to use Debian and not RH. They want to be able
> to configure 1 machine and mirror the setup to each machine in the
> farm, without having to go to each of the remaining 199 and configure
> it by hand. Someone told them that RH made this easy, and no other
> dist could do it!
>
> Someone help me out here! This will be running the RHIC project in
> 1999 here.. I'd love to see Debian get that kind of exposure!
Tim, from my experiences with (much smaller scale but still essentially
the same) mass-duplication of debian, all you need to do is duplicate the
hard disk and change half a dozen (or less) files under /etc:
/etc/hostname
/etc/init.d/network
/etc/hosts
and maybe some others, depending on your particular needs and your
particular hardware setup. e.g. if the hardware is not identical (in
particular, same network card) and identically configured then you will
also need to change /etc/modules.
you probably don't need to change /etc/mailname or the mail configuration
- just make them all masquerade as the domain name if they need to send.
BTW, it will be much easier to do if all the machines have identical hard
disks. then you can just install debian on one disk and use dd to
duplicate the disk, and then run a script to 'individualise' the hostname
and ip address details.
FWIW, i auto-build debian based dialin servers (to be installed at schools
for staff and students) by installing the latest stable release, and then
run a fairly simple script which asks for the host & domain name, and ip
address and then uses ed to modify a handful of config files....the ones
listed above plus stuff in /etc/ppp
it really is easy to do. if you need any help at all i am more than
willing to lend a hand...
I find consistency in design to be one of the nicest features of debian:
I can build a "standard" machine which can be made to perform any
function (workstation, file server, ppp dialin server, mail server,
squid proxy, etc) just by installing the relevant packages. it gives me
an extraordinarily high level of consistency across the machines i have
to look after...they only differences are just the network config, and
the config files for one or two packages.
best of all, if a machine happens to die and i have kept a backup copy
of it's unique config files i can rebuild it very quickly. squid is a
good example - twice i've had the hard drives on a squid box fail under
the heavy load. rebuilding the box was very easy (it takes me about half
a day to build a debian box including unpacking all the hardware from
the packing cases). While i was building the replacement box, I used
linux's IP aliasing to make another machine on the network pretend to
be the proxy server (but with only a tiny 100mb cache spool) so that
customers weren't inconvenienced by the downtime.
As far as I am concerned, the cheaper price of commodity hardware is far
more valuable than any "X"-hour support contract offered by a commercial
*nix vendor. In the X hours i have to wait for their engineer to come
out, i can completely rebuild the machine from spare parts that i have
lying around. Spare parts that I can afford because they are a third
(or less) of the price of the high end gear.
It is undeniable that, for example, Sun harware is more reliable than PC
clone hardware....but it isn't reliable enough to be worth 3 to 5 times
the price. we've got some $30,000 (Australian $) sun boxes at work which
were bought a few months before i started there....if i had been around
at the time, we almost certainly would have bought $5,000 to $10,000 PC
boxes plus a few thousand dollars worth of spare parts instead. power
supplies, hard disks, memory, motherboards, cpus...enough to build a
whole machine or two.
including the cost of the support contract, this would have saved us
over $20,000 per machine. we have 3 of these machines. over $60,000
could have been saved.
OTOH, it's nice to have some ultra sparcs to play with....i may even be
able to rebuild one as a debian sparc box by re-arranging server loads
more efficiently :-)
craig
--
craig sanders
--
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