jjumbii
Posts: 2
Joined: Mon Sep 05, 2011 4:47 pm

Re: How would a bramble work?

Fri Dec 30, 2011 11:03 pm

Well, I have recently taken an interest in this project. I am 13 and although I doubt I will ever use a Raspberry Pi in school, I can't wait to get my hands on a Pi and play around with it.

My main goal is to be able to cluster 5-10 Raspberry Pi's to do certain tasks. I understand the concept of a cluster (bramble in this case) where you have one "master" and many other "nodes". But I was simply clueless when it came to the software aspect.

I found this video, showing 10 Beagle-boards in a cluster doing tasks with R code.



Would it be possible to cluster the devices in a similar way, and distribute tasks on them?

pvgb
Posts: 51
Joined: Sat Oct 15, 2011 9:53 pm

Re: How would a bramble work?

Fri Dec 30, 2011 11:40 pm

It certainly seems possible - I hope to do something like this myself.

A term to search for is "Beowulf Cluster".

The Wikipedia page is a start - http://en.wikipedia.org/wiki/B.....lf_cluster

A quick look around turned up http://fscked.org/writings/clusters/ which seemed reasonable, if a little dated.

It seems that people are still building these clusters,  http://www.debian.org/News/2011/20110729

You may wish to consider a switch rather than hubs - I assume you are looking at the version of the RPi with Ethernet.

Good Luck.

You may wish to look around the forum, there are already some threads discussing "Brambles"

jjumbii
Posts: 2
Joined: Mon Sep 05, 2011 4:47 pm

Re: How would a bramble work?

Fri Dec 30, 2011 11:47 pm

pvgb said:


It certainly seems possible - I hope to do something like this myself.

A term to search for is "Beowulf Cluster".

The Wikipedia page is a start - http://en.wikipedia.org/wiki/B.....lf_cluster

A quick look around turned up http://fscked.org/writings/clusters/ which seemed reasonable, if a little dated.

It seems that people are still building these clusters,  http://www.debian.org/News/2011/20110729

You may wish to consider a switch rather than hubs - I assume you are looking at the version of the RPi with Ethernet.

Good Luck.

You may wish to look around the forum, there are already some threads discussing "Brambles"


Thanks, and yes I am looking into the Model B with Ethernet.

foo
Posts: 52
Joined: Thu Dec 29, 2011 12:49 am

Re: How would a bramble work?

Sat Dec 31, 2011 6:04 am

I'm curious if networking more than 2 RPis through USB (native USB, not a USB->Ethernet adapter) would be possible, as USB 2.0 is >4x faster than the 100MBps ethernet.  I haven't found anything via google, but if plugging say 4 RPis into a powered USB hub could let them talk somehow then the cabling would be much easier and it'd potentially be a lot faster than ethernet.

I suspect it would require a custom smarter USB hub, and couldn't just be done through RPi-side USB drivers though.  They do make USB host-to-host smart bridge cables for connecting 2 computers for file transfers and such, but I've never seen them go for more than 2 machines.

jamesh
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Re: How would a bramble work?

Sat Dec 31, 2011 10:09 am

foo said:


I'm curious if networking more than 2 RPis through USB (native USB, not a USB->Ethernet adapter) would be possible, as USB 2.0 is >4x faster than the 100MBps ethernet.  I haven't found anything via google, but if plugging say 4 RPis into a powered USB hub could let them talk somehow then the cabling would be much easier and it'd potentially be a lot faster than ethernet.

I suspect it would require a custom smarter USB hub, and couldn't just be done through RPi-side USB drivers though.  They do make USB host-to-host smart bridge cables for connecting 2 computers for file transfers and such, but I've never seen them go for more than 2 machines.


I don't think it would be worth the effort - just get a ethernet switch and plug together with that. No real speed difference I don't think once all the over heads are worked out, and you are using as standard system.

I'm not sure how important fast networking is to distributed apps - depends on the problem I suppose, but if they veer to the CPU limited side, the networking is not so important.
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Svartalf
Posts: 596
Joined: Fri Jul 29, 2011 6:50 pm

Re: How would a bramble work?

Wed Jan 04, 2012 5:48 am

JamesH said:

I don't think it would be worth the effort - just get a ethernet switch and plug together with that. No real speed difference I don't think once all the over heads are worked out, and you are using as standard system.

I'm not sure how important fast networking is to distributed apps - depends on the problem I suppose, but if they veer to the CPU limited side, the networking is not so important.



Most problems will benefit from fast networking.  It's why I was hired by a company doing the first 10 gigabit Ethernet channel adapters to help them develop Linux drivers for their hardware back a while ago.

But if your CPU can't produce results faster than the links, it doesn't matter much.  For what we're doing here, unless the GPU's involved in some manners, I suspect the 100Mbits will work well enough.

JerryMcBride
Posts: 3
Joined: Sun Jul 31, 2011 8:18 pm

Re: How would a bramble work?

Tue Jan 10, 2012 2:00 am

I am a bit of a trash picker that happens to live near a fairly well off development. I'm known to drive the streets, the day before trash collection, picking up unwanted computers. And I've found some real doozies too.

The result of my efforts is one of the slickest single image cluster, compile farms, this side of NASA.

I love Linux and I compile source code more often than most people change their socks. To cut down on the compile time, I use my cluster to spread the compile over several nodes. When I get into a big source code build, I can run 10 nodes with one master.

The master is the one I begin my compile on and as more and more threads are called up by the make process, they get migrated out over the network to the least active node. When the compile is completed on any node, the binary is sent back to the master node. So, for instance, instead of one machine compiling a 100 meg source tree, I begin the compile with "make -j 30..."... each new make get's migrated off the master... really, really slick. It makes the network sing. Some day, I'll find enough 1gig nics and make it even faster

I run Gentoo, a MOSIX kernel, a twelve port switch (not hub) and ccache on each node. I was very careful about the nics I use, as I wanted to make certain I could atleast get duplex 100base-t transfers. Compile times are breath taking. I can compile a fairly complicated kernel (lots of drivers and options) in under a few minutes on the worst day. Smaller programs are pretty much a few eye blinks and they are done and ready to use.

MOSIX is available for free, educational use. Just google MOSIX. It comes as a patch that you apply to a vanilla kernel source and it also provides all the tools you'll need to get your cluster up and running.

How this all plays on ARM, I don't know but it would be fun. It would use a lot less power than what I have when running the whole cluster. it's something I'm looking to try with a few of the next gen RaspberryPi's. It'd be cool to see a multicore, high clock rate RP someday, That would make a nice cluster regardless.

setkeh
Posts: 2
Joined: Mon Mar 12, 2012 11:48 am
Contact: Website

Re: How would a bramble work?

Mon Mar 12, 2012 12:03 pm

Hey Guys

I have been Following RPI for quite some time and im am extreamly exited about the upcoming release and i have been bashing around the forums for some time and i read about Brambling the RPI so i gots thinking and followed quite a few tuts on the net to get RPI archlinux running in Qemu.

I have successfully clustered with it with VDE an actual network environment behavior can be achieved and with astonishing results i have done a video on getting the RPI emulated in qemu you can watch that here  ( if im not allowed to post this link please let me know and ill remove it)

[link][/link]

I have also got a tiny repo setup with all of the packages needed to setup the cluster you can brows that (or add it to you pacman.conf) here: http://setkeh.com/arm/ and i used the archwiki for the instructions https://wiki.archlinux.org/index.php/TORQUE this method is quite simple and really effective for allot of clustering needs i will also be doing some videos on this in the next few days (just as soon as i grind off some sharp edges ) so stay tuned if your interested

cheers for reading my tirade :D

DevilWAH
Posts: 20
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Re: How would a bramble work?

Fri May 04, 2012 9:23 am

100MB network is going to be plenty for any kind of cluster the Raspberry is able to run.

you have two types of clusters,

The work unit model, where a package of work is sent to each node to be worked on and the results returned. (like the folding at home project). In this case each work unit may take any thing from a few seconds to complete to several hours/days. This is a good method for repetitive work unit that can be broken up in to chunks.

The second method is when processes communicate in real time between the nodes. so rather than multiply copies of an application running on each node you have one central multi threaded application using each node like a separate CPU.

for the second to work well you need very low latency networking, things like infiband which have 1 microsecond delay. This requires network cards and a network infrastructure that run in the the 10's of thousands. This is a highly specialised field and some thing that way out of the raspberrys filed to do any usefull work.

The first type of cluster however required neither high bandwidth nor low latency. A work package is generally a few meg of data each. and for some thing like folding at home each unit takes a node about 6 - 8 hours to complete. In this case the bottle neck is the speed the node can complete the unit, the extra 2 or 3 seconds lost in network speed are not going to affect the over all speed.

there is a good cluster software called "CONDOR" and I think the reaspberry would work well. Although how effective it would be in terms of CPU power remains to be seen

@Setkeh some good looking stuff there

pstan
Posts: 1
Joined: Thu May 24, 2012 4:30 pm

Re: How would a bramble work?

Thu May 24, 2012 4:45 pm

Anyone know is it possible to run Apache Hadoop on Paspberry Pi? Can't find any minimum requirement on the web.

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Gert van Loo
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Re: How would a bramble work?

Thu May 24, 2012 7:44 pm

I am still hoping one day we will have DSI -> CSI data exchange clusters. ~2 Gbits of RAW data!

iandev
Posts: 1
Joined: Wed Aug 15, 2012 5:51 pm

Re: How would a bramble work?

Wed Aug 15, 2012 5:57 pm

Look into MPI (message passing interface) and OpenMPI.

Here is an article that was in linux magazine titled "MPI in Thirty Minutes":
http://www.linux-mag.com/id/5759/

This article is not strictly about setting up OpenMPI on a raspi cluster, but it it should work the same.

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