[Beowulf] What services do you run on your cluster nodes?

Prentice Bisbal prentice at ias.edu
Tue Sep 23 18:33:03 PDT 2008

Prentice Bisbal wrote:
> The more services you run on your cluster node (gmond, sendmail, etc.)
> the less performance is available for number crunching, but at the same
> time, administration difficulty increases. For example, if you turn off
> postfix/sendmail, you'll no longer get automated e-mails from your
> system to alert you to a problem.
> My question is this: how extreme do you go in disabling non-essential
> services on your cluster nodes? Do you turn off *everything* that's not
> absolutely necessary, do you leave somethings running to make
> administration easier?
> I'm curious to see how everyone else has their cluster(s) configured.
Thanks for all the interesting responses. Very informative and helpful. 
I'm surprised no one mentioned unnecessary cluster configuration. The 
stock kernels from the distros have support for just about every feature 
and piece of hardware enabled. I understand the modular nature of the 
kernel, but I'm sure for every kernel module that's added, some 
addtional work must be added to the core kernel to load that module and 
communicate with it, or check for when it needs to be loaded.

I'm looking the output of lsmod on one of my new cluster nodes (running 
ROCKS - I haven't configured it yet), and I the following modules listed 
in the output, that I don't think have any purpose on a cluster node 
(please correct me if I'm wrong):

battery (for laptops?)
backlight (for laptops?)
 + plus a lot of iptables related modules

There are more that are questionable, but they may in fact be necessary 
- I'm not an encyclopedia on kernel modules. Is anyone else surprised 
that IP tables is configured on a cluster node. Everytime an IP packet 
comes in, the kernel must now stop to check it and make sure it meets 
the criteria to be accepted. That's GOT to take some CPU time.

I wonder how many cluster nodes out there are running LVM, since RHEL 
always insists on setting it up.


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