Projects (USIU)

Project: Pi Based Cluster

Course: APT 4030 - Parallel Computing

About:

In this project, we will build a cluster of identical raspberry pi nodes, networked together and running parallel processing software that allows each node in the cluster to share data and computation.

Objective(s):

Building a cluster computer powered by raspberry Pi that could be used to develop and run parallel and distributed programs. In doing so, the following goals could be achieved.

Practical understanding of building parallel systems.

• Experiment with different configurations to achieve better performance.
• Familiarity with MPI (Message Passing Interface) API for parallel programming.
• Familiarity with raspberry pi micro computers useful for rapid hardware prototyping.

Building the system:

Components:

• Raspberry Pi Model B
• Storage - SD cards
• Ethernet cables
• Power supply
• Linux OS
• There is an array of different possibilities.
• MPI library
• MPICH or OpenMPI
• Ethernet switch and Router
• A switch that we can use without interruption during the lab works.

Implementation:

Ideally the project will be implemented in stages, starting with configuring the first two nodes and then scaling to add all other additional nodes.

Resources:

There are many resources that we will use including Raspberry Pi Foundation https://www.raspberrypi.org/

Prof Simon Cox, Making a Raspberry pi super computer, University of Southampton http://coen.boisestate.edu/ece/raspberry-pi/

Configuring the nodes, step by step guide

• First, configure the first node

When this is done, its easier to clone as many nodes as wanted.

1. Get the OS image raspberrypi.org/download

After many false starts, we were content to just use Rasbian Weezy 5.5

2. Get image into a the sdcard

On Linux:

#dd if=/media/yourMachine/Images/2015-05-05-raspbian-wheezy.img of=/dev/sdb bs=512 conv=noerror,sync

3. Boot the Pi

Great suspense it anything did not go as planned.

If there is an error with the card or any other thing, nothing will show up on the screen, if the Pi is overwhelmed it will take forever to boot. Rasbian is ideal because it has been tested and has a descent first boot time.

4. Configuration on first boot

These configurations can be done later with raspi-config or ideally done on the first boot.

• Expand image to fill card
• Change the password
  laxmi

• Change hostname (node1 or nodex)

5. Re boot

user: pi (has root priviledges) password: laxmi

Refresh update repo packages and update the software

#sudo apt-get update && sudo apt-get upgrade -y

Choose your poison: I prefer having my emacs

#sudo apt-get install emacs

you only get version 23, will have to compile to use version 24)

6. Refresh and update the softwares, if not done yet.

#sudo apt-get update && sudo apt-get upgrade -y

7. Get Fortran, (strange but we need it)

#sudo apt-get install gfortran

8. Before getting Argonne MPICH

Resource: http://www.mpich.org/documentation/guides/

The have great resources not just the the MPICH library

#mkdir /home/pi/mpich3 $ cd ~/mpich3

9. Get MPICH sources from Argonne

#wget http://www.mpich.org/static/downloads/3.1.4/mpich-3.1.4.tar.gz

Resource: http://www.mpich.org/downloads - Get latest stable

10. Unpack them.

#tar xfz mpichXXX.tar.gz

11. Planning a clean place for install

#sudo mkdir /home/rpimpi/

#sudo mkdir /home/rpimpi/mpich3-install

12. Make a build directory, and go to the build

#mkdir /home/pi/mpich_build $ cd /home/pi/mpich_build

13. Configure the build

This will take a while, you can get the cards ready, you can play while the configurations takes place.

#sudo /home/pi/mpich3/mpichXXX/configure -prefix=/home/rpimpi/mpich3- install

14. Make

What ever it took the last, you can +1

#sudo make

15. Install the files

It can take a bit of time, but not any way close to the last two stages.

#sudo make install

16. Add the place that you put the install to your PATH

#export PATH=$PATH:/home/rpimpi/mpich3-mstall/bin

17. Or Note to permanently put this on the PATH you will need to edit .profile

#emacs -/.profile

and add lines below:

#Add MPI to path (This is just a comment for later) PATH="$PATH:/home/rpimpi/mpich3-install/bin"

18. Verify if the install were succesful

#which mpicc /home/rpimpi/mpich3-install/mpicc $ which mpiexec

19. Go /home and set a place for your first test

#cd ~

#mkdir mpi_first_test $ cd mpi_first_test

20. Now testing MPI on single node

#mpiexec -f machinefile -n <number> hostname

where machine file contains a list of IP addresses (in this case just one) for the machines

21. How this supposed to be done

a) Get your IP address

#ifconfig

b) Put this into a single file called machinefile

#emacs machinefile

c)            Add this line:

192.168.1.161 [or the ip is ... ]

22. Now test if the machinefile

# mpiexec -f machinefile ~n 1 hostname

Output should be: node1 ('hostname')

23. Little C code using MPI on Pi to calculate Pi

Don't worry, we shall not write the c code our selves, but MPICH has some example codes we can run.

# cd /home/pi/mpi_fist_test

# mpiexec -f machinefile -n 2 /home/pi/mpich3/examples/cpi

Output is should be

Process 0 of 2 is on raspberrypi Process 1 of 2 is on raspberrypi

pi is approximately 3.141 5926544231318, Error is 0.0000000008333387

24. Celebrate!

This calls for a celebration! (Seriously!)

25. Shut down

# sudo poweroff