[Beowulf] Green Cluster?

Geoff Galitz geoff at galitz.org
Sat Jul 19 13:42:00 PDT 2008

Many, many, many moons ago I wrote a plugin for the clustering framework
(now defunct) that we used and I was a developer on back at UC Berkeley.  It
was quite simple... it simply checked to see if jobs were in the queue, if
not it looked to see what nodes were free (using OpenPBS/Torque native
commands), did the necessary parsing of a few backend config files and then
issued standard shutdown commands to the idle nodes.  When jobs started to
back up in the queue, the plugin used WOL to start up nodes.

It was in perl and less than 100 lines.

I easily could have used IPMI instead, but many of the boxes we were using
had better WOL support than IPMI.  WOL is standard while IPMI can vary from
vendor to vendor... so if your needs are no more complex than this, WOL is a
good way to go.


Geoff Galitz
Blankenheim NRW, Deutschland

-----Original Message-----
From: beowulf-bounces at beowulf.org [mailto:beowulf-bounces at beowulf.org] On
Behalf Of Nathan Moore
Sent: Samstag, 19. Juli 2008 22:02
To: beowulf at beowulf.org
Subject: Re: [Beowulf] Green Cluster?

I think the feature you're looking for is "Wake on LAN",

I've wondered similar things - the small cluster I run for a
students/departmental use is generally off, except when I'm teaching
computational physics, or have a student interested in a specific research
project.  It would be nice to be able to "turn on" a few machines (from
home, at 11:30pm) when I have to run something substantial.  

If you find a good step-by-step resource describing how to do this, I'd love
to hear about it.

Nathan Moore

On Sat, Jul 19, 2008 at 11:53 AM, Perry E. Metzger <perry at piermont.com>

	fkruggel at uci.edu writes:
	> I am wondering whether there is any mechanism to automatically
	> power down nodes (e.g., ACPI S3) when idle for some time, and
	> automatically wake up when requested (e.g., by WOL, some cluster
	> scheduler, ssh). I imagine that I could cut down power & cooling
	> on our system by more than 50%. Any hints?
	Depending on the motherboard, there are ways to do this. You can do
	wake on network and other tricks. However, if you would really save
	half the power, that implies that your cluster is half idle. If it
	really half idle, why aren't you simply shutting half of it down?
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Nathan Moore
Assistant Professor, Physics
Winona State University
AIM: nmoorewsu 
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