[Beowulf] best linux distribution

[Bogdan Costescu]

On Mon, 8 Oct 2007, Robert G. Brown wrote:

> RHEL/Centos are good where vendors require "binary compatibility" on 
> closed source software, as the standard of said binary 
> compatibility.

What strikes me in this whole discussion is the ideea of 'one 
distribution fits all' when applied to all nodes of a cluster and all 
applications that run on that cluster. In the days of PXE booting, 
with several solutions readily available for either building a node 
from scratch (like kickstart) or booting a prebuilt setup with 
NFS-root or ramdisk, what's so difficult in matching on request a 
node, an application and a distribution/custom setup ?

Real case: A quantum mechanics code that we have bought some years ago 
was provided only as staticly-linked binaries. They have worked fine 
on the current distros at that time and we have succesfully used them 
on CentOS-3 (2.4 kernel). However we discovered the hard way on the 
new CentOS-5 (2.6 kernel) that the statically linked binaries didn't 
work anymore as the kernel interfaces have changed - but, after a few 
lines were changed in the config files and the nodes rebooted, the 
binaries were again happily running in their required configuration.

Of course, the admin is responsible in defining which 
distributions/custom setups can run on a certain node, based on the 
hardware of that node and the kernel of the distribution/custom setup. 
But after this is done, the user can limit his/her jobs to running on 
these nodes or ask the queueing system to set up a node according to 
the requirements of the job (I think that term is 'provisioning'). 
Sure, it helps in this case to run a distribution with long support 
(like RHEL/CentOS/SL, SLES or Ubuntu LTS) such that you don't have to 
waste too much time yourself with updates, especially security related 
ones.

> Far short of Debian, but plenty big enough to include just about all 
> mainstream useful packages for any cluster or LAN.

I'm making sure that any cluster related package that is part of the 
default distribution is not part of what the nodes get to run. Why ? 
Because very often the common ground options used for building the 
package (which is a good idea for a widely used distribution) don't 
fit _my_ setup. So, I take the fact that the distibution offers me all 
the needed tools as a fallback, but I'm always trying to match as well 
as possible all the components. And if you search the archives of the 
LAM/MPI mailing lists you'll see the larger picture...

-- 
Bogdan Costescu

IWR - Interdisziplinaeres Zentrum fuer Wissenschaftliches Rechnen
Universitaet Heidelberg, INF 368, D-69120 Heidelberg, GERMANY
Telephone: +49 6221 54 8869, Telefax: +49 6221 54 8868
E-mail: Bogdan.Costescu at IWR.Uni-Heidelberg.De