Transcript Poor Mans Cluster

Poor Mans Cluster (PMC)
Johny Balian
Outline
What is PMC
 How it works
 Concept
 Positive aspects
 Negative aspects
 Good and Bad Application ideas
 Monte Carlo example
 Q&A

What is it?

PMC is a library for PHP

Provides parallelization methods like MPI

Written in PHP

Open source, still in beta stage, you can participate on:
http://sourceforge.net/projects/poormanscluster/
How it Works
1) Master sends jobs to Slaves
Slave 1
Slave 2
Master
Slave 3
Slave 4
How it Works
2) Master waits, slaves execute job
Slave 1
Slave 2
Execute job
Master
Slave 3
Slave 4
While(#results != #slaves)
sleep(1);
How it Works
3) Slaves are done, they can either send result to Master
or to another place (eg: database)
The code of the slaves and the results are stored in files
(we’ll see later how communication is done)
Slave 1
Slave 2
Master
Slave 3
Slave 4
Concept
The concept is the same as MPI
 But MPI is limited, its not practical to use
on the web, you can’t install it on 4$
servers! That’s where PMC comes
handy, its main idea is to make it run on
almost any web server.
 Hence the name, Poor Mans Cluster

Positive Aspects (to name a few)




Very cheap to maintain, servers cost 4$/month, a
cluster of 100 slaves will run at 400$/month (relatively
cheap)
Easy to install, upload the files on the slaves and add
the slaves to the masters config file, the master takes
care of everything after that.
Open source all the way (Linux,Apache,PHP,PMC)
Very easy to use for web applications since PHP is a
web language.
…
Negative Aspects

Big communication overload (a msg
takes from 1 - 3 seconds)
Good Application Ideas…

PMC is mainly used for high bandwidth web
applications, such as crawling the internet, because
PMC is installed on web servers which have very high
speed internet connections.
 100 slaves with 1mbps each = 100 mbps for the
application!
 The applications can range from security to anything
you can think of, example of security: you can tell the
slaves to ping a website (DoS) with large packets, this
way you can test if the website is vulnerable to DoS
attacks… (not recommended but doable!)
 You can make a powerful search engine by crawling
the web using the slaves…
Bad Application Ideas
Applications that heavily rely on the
processor are not recommended unless
you have dedicated servers (over
100$/month)
 Examples of bad applications for PMC
are: Monte Carlo
Genetic Algorithms…

Monte Carlo example
Master sends the jobs to the slaves
Slave 1
Slave 2
Master
Slave 3
Slave 4
Monte Carlo example
The slaves will fetch random numbers from random.org
Slave 1
Slave 2
Master
Slave 3
Slave 4
While(#results != #slaves)
sleep(1);
Random.org
Monte Carlo example
Slave 1
Slave 2
Master
Slave 3
Slave 4
While(#results != #slaves)
sleep(1);
true
Execute job
Monte Carlo example
Slave 1
Slave 2
Master
Slave 3
Slave 4
While(#results != #slaves)
sleep(1);
Calculate average and output
false
Source Code
Screenshot
Questions?