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GRAPPOLO a supercomputer in a superbox

Grappolo is a project designed to teach cluster computation.

 imgp9498.jpg We have prototyped and developed a portable micro cluster computer (replicating the functioning of the biggest cluster computer facility in the southwest UK ). This tool is similar to the Raspberry pi cluster developed at Southampton University but is aimed towards teaching Geographic Information Systems methods rather than raw computation, it is very low cost ( ~ £130), portable and a perfect replica of an operating system running on a true high performance cluster computer.

This is still an an ongoing project! Not finished yet. We are working on the OS/ software installation and we will update this page as soon as grappolo will work smoothly fine.



  • Build a micro cluster compurer with the same operating system and software of a real HPC (High Performance Computer) for simulating big data processing.
  • Make it as small as possible so that grappolo can fligh in your hand lugage toghether with your laptop, book, toothbrush and newspaper.
  • Make it awsome so when you test supercomputing in a pub it will attract people's attention and they might want to learn more about it.
  • Make it low cost and open source so that is potentially replicable in schools or by any V2 open minded citizens willing to learn new amazing stuff.

Software and hardware

We used 3 Raspberry pi's running a light distribution of Linux operating system. Below you can find codings for software installation and hardware assembling.
For the best box ever conceived in the history of boxes….
We used an awesome reddish perspex and sawed an alluminium squared box section 15×15.

Project team and collaborators

  • Stefano Casalegno (Project leader)
  • Andrew Cowly (brainstorming - software / OS installation)
  • Oliver Hatfield (box design and construction)
  • Andy Smith (software ideas support / cabling)
  • Victoria O'Brien (software OS / installation)
  • Giuseppe Amatulli (software applications for teaching)

This protect is sponsored by we are a not for profit organization in the UK helping people to learn open source technology for spatio-temporal data analyses, modelling and big data processing.

List of material

TOTAL COSTS : 136.75 shipping and VAT included

Installing OS

  1. Check that your SD card is not trash
  2. Plug Ethernet cable from raspi 1 to home router
  3. Insert SD in raspberry,
  4. power raspi 1
  5. Open a terminal using a computer connected to the home router (via wireless or cable)

check your ip adress

  ifconfig | grep "inet addr"
        inet addr:  Mask:
        inet addr:  Bcast:  Mask:

search for the ip adress of the raspberry pi

  sudo nmap -sP
  Starting Nmap 5.21 ( ) at 2015-05-23 15:24 BST
     Nmap scan report for Unknown-28-32-c5-ae-4e-19.home (
     Host is up (0.0029s latency).
     MAC Address: 28:32:C5:AE:4E:19 (Unknown)
     Nmap scan report for ace.home (
     Host is up.
     Nmap scan report for Unknown-e8-06-88-9c-0f-66.home (
     Host is up (0.10s latency).
     MAC Address: E8:06:88:9C:0F:66 (Unknown)
     Nmap scan report for raspberrypi.home (
     Host is up (0.015s latency).
     MAC Address: B8:27:EB:65:6C:FF (Unknown)
     Nmap scan report for BThomehub.home (
     Host is up (0.013s latency).
     MAC Address: D0:84:B0:D7:AC:30 (Unknown)
     Nmap done: 255 IP addresses (5 hosts up) scanned in 5.44 seconds

You are now ready to connect to raspi1 via ssh, default login and pass are pi, raspberry.

  ssh pi@

you are loged in the raspberry pi. Next steps are easy to do with the raspi-config GUI:

  sudo raspi-config
  1. Expand file system - Resize the partition
  2. Change password to masterpi
  3. Set time zone : internationalisation –> london
  4. Set the memory split and change the value to 16 (in advanced options)
  5. change hostname “ raspberry” to “grappolo” (in advanced options)
  sudo apt-get update
  sudo apt-get upgrade
  sudo reboot
  ssh pi@

Add user admin (administartor) and remove user pi.
Password for user “admin” = “admin” …old pass for pi was masterpi

sudo useradd -m admin
sudo passwd admin #admin
sudo nano /etc/group
# Go through the file adding ,ad to the end of all of the groups that pi is in.  eg:   " adm:x:4:pi,admin  "
ssh -X admin@
chsh -s /bin/bash #default terminal is bash
sudo userdel pi

Set connections configurations

Connect the grappolo cluster to the outside world

We will generate a dynamic ip address to connect to the head node “grappolo” to the outside world. This will be be physically done ether via wifi dongle or via a usb-ethernet adapter depending on our working environment.

Connect nodes within the grappolo cluster

Within the cluster we create a static ip network using the Ethernet ports of each of the 3 raspi. The /etc/network/interface configuration file determine the above parameters. We need to insert the name of the wifi network and password wile connecting using the wifi dongle or we need to uncomment the two eth1 lines if we are using an ethernet connection from the cluster to the external world. The grappolo configuration using the wifi dongle looks like this:

pi@grappolo ~ $ cat /etc/network/interfaces
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
# To connect via usb ethernet adaptor instead of wifi, uncomment the next two lines
#auto eth1
#iface eth1 inet dhcp
allow-hotplug wlan0
auto wlan0
iface wlan0 inet dhcp
#wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
       wpa-ssid "NETWORK_NAME"
       wpa-psk "NETWORK_PASSWORD"

Next we need to reboot and log in via the usb dongle or ethernet-usb:

     sudo reboot
     ssh -X pi@

And the resulting connection configuration is the following

pi@grappolo ~ $ ifconfig
eth0      Link encap:Ethernet  HWaddr b8:27:eb:b6:4b:a5  
          inet addr:  Bcast:  Mask:
          RX packets:69 errors:0 dropped:0 overruns:0 frame:0
          TX packets:23 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:9100 (8.8 KiB)  TX bytes:3231 (3.1 KiB)
lo        Link encap:Local Loopback  
          inet addr:  Mask:
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:72 errors:0 dropped:0 overruns:0 frame:0
          TX packets:72 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:6288 (6.1 KiB)  TX bytes:6288 (6.1 KiB)
wlan0     Link encap:Ethernet  HWaddr 00:87:31:13:37:aa  
          inet addr:  Bcast:  Mask:
          RX packets:455 errors:0 dropped:0 overruns:0 frame:0
          TX packets:221 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:104200 (101.7 KiB)  TX bytes:29337 (28.6 KiB)

To read your configuration information (address; netmask; network; broadcast; gateway) you can type:

   pi@grappolo ~ $ ifconfig | grep -A1 eth0 | tail -1  
        inet addr:  Bcast:  Mask:
   pi@grappolo ~ $ netstat -nr | tail -2 | awk '{if(NR==1)print "Gateway "$2 \\ 
                   else print "Destination "$1 }' 

Gateway Destination We use the 10.141.255 internal static ip address to avoid any inconvenient ip-adress overlap between the dhcp extrnal and static internal cluster network configurations.

Install Software

R language and environment for statistical computing

mkdir R_HOME
mv R-3.1.2.tar.gz R_HOME/
cd R_HOME/
tar zxvf R-3.1.2.tar.gz
cd R-3.1.2/
sudo apt-get install gfortran libreadline6-dev libx11-dev libxt-dev
sudo make install
# get a coup of tea and start watching Battleship Potemkin you have an hour to wait

PROG.4 - GDAL/OGR / GRASS geospatial libraries

sudo apt-get install grass grass-doc grass-dev

Emacs editor

… for people like Giuseppe or Pieter refusing to type on any other black squared thing with a cursor!

sudo apt-get install emacs

Install other useful tools

I like the bash locate command.

sudo apt-get install mlocate
sudo updatedb

Setting Up an NFS Server

The default installation of Grid Engine assumes that the excutables corresponding to the sge command are found on a $SGE_ROOT directory sitting on a shared filesystem accessible by all hosts in the cluster more info here.
For this purpose, we use a Network File System (NFS) which is a distributed file system allowing a user on a client computer to access files over a network. We are going to create and share the /usr/local/apps folder between master and slave nodes and be able to install the Grid engine executables and configuration files in the slave nodes. We first install the nfs server in the master:

sudo apt-get install nfs-kernel-server portmap nfs-common
sudo nano /etc/exports
# append  "/usr/local/apps,sync)" to the end of /etc/exports file
sudo service rpcbind restart
sudo /etc/init.d/nfs-kernel-server restart

Next you need to switch into appropriate Linux Run Level (e.g. A run level is a state of init and the whole system that defines what system services are operating.) Raspi by default is set to a state of run level 2 - Local Multiuser with Networking but without network service (like NFS) - and we want to switch to run level 3 - Full Multiuser with Networking. Once we are in level 3 we can use the two update-rc.d command below to allow automatic starting of the nfs servers at reboot.

sudo nano /etc/inittab
# to set default runlevel = 3
# change id:2:initdefault with: id:3.... it should look like this:
# The default runlevel.
# id:3:initdefault:
sudo update-rc.d nfs-kernel-server defaults
sudo update-rc.d rpcbind defaults
sudo apt-get install nfs-kernel-server portmap nfs-common
sudo nano /etc/exports # add the export as above
sudo service portmap start
sudo reboot
/etc/init.d/nfs-kernel-server status to check nfs service status
to check your default run level
if is not running at reboot try the lines below
sudo apt-get purge rpcbind
sudo apt-get install nfs-kernel-server portmap nfs-common
sudo nano /etc/exports # edit the exports as above
sudo service portmap start # this didn't actually worked
sudo reboot

Later we will create a folder in the client server @node1 and mount in as shared with the correspondent folder in grappolo.

Do a partial backup

Shut down the raspi, remove the sd card and insert it in a linux machine. Copy sd image file to computer disk as back up.

   umount /dev/sdb1
   umount /dev/sdb2
   sudo dd bs=4M if=/dev/sdb of=raspian_grassR_masterpw.img

Install Grid Engine - Master pi

Grid Engine is typically used on a computer farm or high-performance computing (HPC) cluster and is responsible for accepting, scheduling, dispatching, and managing the remote and distributed execution of large numbers of standalone, parallel or interactive user jobs. It also manages and schedules the allocation of distributed resources such as processors, memory, disk space.

We use the open source Open Grid Schcheduler| as batch-queuing system. This is one of the most common software used in HPC clusters around the world and we aim at teaching its use.
We will first install some dependency packages that I've found missing in raspian.

sudo apt-get install csh  # csh shell
sudo apt-get install libpam0g-dev
sudo apt-get install lesstif2-dev

Then compile

tar zvxf GE2011.11p1.tar.gz
cd GE2011.11p1/source
export LDFLAGS=-L/usr/lib/arm-linux-gnueabihf
./aimk -no-java -no-jni -no-secure -spool-classic -no-dump -only-depend
./aimk -no-java -no-jni -no-secure -spool-classic -no-dump depend
./aimk -no-java -no-jni -no-secure -spool-classic -no-dump -no-qmon

Have a tea and a siesta… for a 30min …

The compilation succeeded. First edit the /etc/hosts file making sure the internal ip-address is correct.       localhost
::1             localhost ip6-localhost ip6-loopback
fe00::0         ip6-localnet
ff00::0         ip6-mcastprefix
ff02::1         ip6-allnodes
ff02::2         ip6-allrouters  grappolo

Now install as follow:

sudo mkdir -p /usr/local/apps/sge/2011.11p1
sudo su
chmod 777 /usr/local/apps/sge/2011.11p1/
export PATH=$PATH:/usr/local/apps/sge/2011.11p1/bin/linux-arm/
export SGE_ROOT=/usr/local/apps/sge/2011.11p1
cd  /usr/local/apps/sge/2011.11p1
scripts/distinst -all -local -noexit

The interactive install console will start and we have follow similar settings to those suggested @ FslSGE :

  • press enter at the intro screen
  • press “y” and then specify admin as the user id
  • leave the install dir as /opt/sge
  • You will now be asked about port configuration for the master, normally you would choose the default (2) which uses the /etc/services file
  • accept the sgeqmaster info * You will now be asked about port configuration for the master, normally you would choose the default (2) which uses the /etc/services file * accept the sgeexecd info
  • leave the cell name as “default”
  • Enter grappolo as the appropriate cluster name when requested
  • leave the spool dir as is
  • press “n” for no windows hosts!
  • press “y” (permissions are set correctly)
  • press “y” for all hosts in one domain
  • For the Java available on your Qmaster answer “n” for the wish to use SGE Inspect or SDM then enable the JMX MBean server
  • press enter to accept the directory creation notification
  • enter “classic” for classic spooling (berkeleydb may be more appropriate for large clusters)
  • press enter to accept the next notice
  • enterthe default “20000-20100” as the GID range (increase this range if you have execution nodes capable of running more than 100 concurrent jobs)
  • accept the default spool dir or specify a different folder (for example if you wish to use a shared or local folder outside of SGE_ROOT
  • email address enter default (no email)
  • press “n” to refuse to change the parameters you have just configured
  • press enter to accept the next notice
  • press “y” to install the startup scripts
  • press enter twice to confirm the following messages
  • press “n” for a file with a list of hosts
  • enter the node1 as names of your hosts who will be able to administer and submit jobs (enter alone to finish adding hosts)
  • shadow hosts (press “default”)
  • choose “1” for normal configuration and agree with “y”
  • press enter to accept the next message and “n” to refuse to see the previous screen again and then finally enter to exit the installer

You will have to go through the same process for node1
Create a new /etc/profile.d/ scripts with links of our system configurations and grid engine environment. Then reboot and start the grid engine

sudo leafpad /etc/profile.d/
# add the following 3 lines to this script.
export SGE_ROOT=/usr/local/apps/sge/2011.11p1
export SGE_CELL="default"
export PATH=$PATH:/usr/local/apps/sge/2011.11p1/bin/linux-arm/
# save and close
sudo reboot
ssh ssh -X pi@ # again from your computer and start the sge
etc/init.d/sgemaster.grappolo start
# cd $SGE_ROOT/default/common/
# ./sgemaster start
# ./sgeexecd start

Do a partial backup

Shut down grappolo, remove the sd card and insert it in a linux machine. Copy sd image file to computer disk as back up.

   umount /dev/sdb1
   umount /dev/sdb2
   sudo dd bs=4M if=/dev/sdb of=raspian_SGEgrassR_masterpw.img

Install Grid Engine on Nodes

First add the node1 ip-address to the hosts list in the master node grappolo

sudo nano  /etc/hosts
# append this "      node1" at the end of file 

Clone node1

Insert a new micro sd card into a laptop (in our case is mounted at /dev/mmcblk0 ; unmount the card and copy the “.img” we have previously created with raspian OS grass and R installed.

umount /dev/mmcblk0p1
umount /dev/mmcblk0p2
sudo dd bs=4M if=/media/leXar/raspian_grassR_masterpw of=/dev/mmcblk0

Log into the pi-node :

  • change hostname “grappolo” to “node1” ;
sudo nano /etc/hostname 
  • change password to node1pw and later node2pw
  • edit the /etc/network/interfaces file as below:
auto lo
iface lo inet loopback
auto eth0
allow-hotplug eth0
iface eth0 inet static
address # use ....141.0.2 in node2
  • Add ip-address of node1, node2 and grappolo in the /etc/hosts file list as below       localhost
::1             localhost ip6-localhost ip6-loopback
fe00::0         ip6-localnet
ff00::0         ip6-mcastprefix
ff02::1         ip6-allnodes
ff02::2         ip6-allrouters  grappolo      node1      node2

Link grid engine environment and executables in a new script that looks like this

cat /etc/profile.d/
export SGE_ROOT=/usr/local/apps/sge/2011.11p1
export PATH=$PATH:/usr/local/apps/sge/2011.11p1/bin/linux-arm/

Now shut-down node 1 and create a micro sd card for node 2 as above and of course replacing “node1” with “node2”. Then Plug node1, node2 and grappolo togheter and continue the installation mounting nfs shared folders

Link the /usr/local/apps folder in grappolo using the nfs:

  • can create a folder in node1
  • mount it in as shared with the correspondent folder in grappolo.
sudo mkdir /usr/local/apps
sudo mount grappolo:/usr/local/apps /usr/local/apps

To allow auto mount /usr/local/apps in node1 and 2 at reeboot, edit the /etc/fstab file and append the following line :

grappolo:/usr/local/apps	/usr/local/apps	nfs	rsize=8192,wsize=8192,timeo=14,intr,rw	0	0

Allow grappolo to ssh into node1 without a password Exit from node1, generate a key pair and copy the key from grappolo to node1.

pi@node1 exit
pi@grappolo ~ $ ssh-keygen -t rsa -P ""
pi@grappolo ~ $ ssh-copy-id admin@node1
pi@grappolo ~ $ ssh admin@node1
pi@node1 ~ $ 

Allow node1 to ssh into grappolo without a password (the other way around from before: Log in from node1, to grappolo

generate a key pair and copy the key from grappolo to node1.

pi@node1 ~ $ ssh-keygen -t rsa -P ""
pi@node1 ~ $ ssh-copy-id 'admin@grappolo'
pi@node1 ~ $ ssh admin@grappolo
pi@grappolo ~ $ 

Install Hadoop dependencies and environment

Install Java

 sudo apt-get install openjdk-7-jdk
 java -version
 #java version "1.7.0_75"
 #OpenJDK Runtime Environment (IcedTea 2.5.4) (7u75-2.5.4-1~deb7u1+rpi1)
 #OpenJDK Zero VM (build 24.75-b04, mixed mode)

Create and config Hadoop user and groups

 sudo addgroup hadoop
 #Enter new UNIX password: 
 #type return for the next 4 questions
   * Give hduser the ability to sudo 
 sudo adduser hduser sudo # gives the ability to hduser sudo
   * Login as hduser  
 ssh hduser@

Setup ssh

Generate a key pair to login without password

 ssh-keygen -t rsa -P ""

Copy public key into user authorized key store

   cat ~/.ssh/ >> ~/.ssh/authorized_keys

Verify if ssh works on localhost without password for hduser

 ssh localhost
 exit # Go back to previous shell (pi/root).

Install Hadoop

sudo tar -vxzf hadoop-1.2.1.tar.gz -C /usr/local
cd /usr/local
sudo mv hadoop-1.2.1/  hadoop
sudo chown -R hduser:hadoop hadoop

Configure the user environment

nano .bashrc
#add to file:
export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-armhf
export HADOOP_INSTALL=/usr/local/hadoop
# save and close .bashrc
sudo reboot

Configure Hadoop

login as hduser

hadoop version
#Hadoop 1.2.1
#Subversion -r 1503152
#Compiled by mattf on Mon Jul 22 15:23:09 PDT 2013
#This command was run using /usr/local/hadoop/hadoop-core-1.2.1.jar

Set up environment that defines some overall runtime parameters:

nano /usr/local/hadoop/conf/
#edited at end:
export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-armhf


nano /usr/local/hadoop/conf/core-site.xml
#Add these lines in file:
    <value>/fs/hadoop/tmp</value>    <description>Sets the operating directory for Hadoop data.
    <value>hdfs://localhost:54310</value>    <description>The name of the default file system.  A URI whose
    scheme and authority determine the FileSystem implementation.
    The URI's scheme determines the config property (fs.SCHEME.impl) naming
    the FileSystem implementation class.  The URI's authority is used to
    determine the host, port, etc. for a filesystem.  


nano /usr/local/hadoop/conf/mapred-site.xml
#added following:
    <description>The host and port that the MapReduce job tracker runs
    at.  If "local", then jobs are run in-process as a single map
    and reduce task.


nano /usr/local/hadoop/conf/hdfs-site.xml
#added following:
    <description>Default block replication.
    The actual number of replications can be specified when the file is created.
    The default is used if replication is not specified in create time.

Create working directory and set permission:

sudo mkdir -p /fs/hadoop/tmp
sudo chown hduser:hadoop /fs/hadoop/tmp
sudo chmod 750 /fs/hadoop/tmp/

Format the working directory:

/usr/local/hadoop/bin/hadoop namenode -format

Create node 1, 2 ...

Rename the cloned operating system pi@head as pi@node1 go to raspi-config –

> advanced hostname\\


ename the cloned operating system pi@head as pi@node1 Change password to node1pw Change static ip address to

 sudo nano /etc/network/interfaces

wiki/raspi_hpc.txt · Last modified: 2021/01/20 20:36 (external edit)