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

[Prentice Bisbal]

Prentice Bisbal wrote:
> 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.
>>
>>  

I meant unecessary *kernel* configuration in the 3rd sentence below.
> 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):
>
> parport_pc
> lp
> parport
> pcspkr
> 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.
>
> -- 
> Prentice
>
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