The document provides instructions for building a Beowulf cluster from commodity computers connected via Ethernet. Key steps include: 1. Installing Linux on each node and connecting them via Ethernet. 2. Creating a common user on each node and installing OpenSSH for remote login access between nodes. 3. Generating SSH keys to allow passwordless login between nodes. 4. Installing and configuring MPICH software to enable message passing between nodes for parallel processing.

1. CLUSTERING MANUAL
Introduction:
Parallel computing is a form of computation in which many calculations
are carried out simultaneously operating on the principle that large
problems can often be divided into smaller ones, which are then solved
concurrently ("in parallel")
What Is Cluster:
In a computer system, a cluster is a group of servers and other resources
that act like a single system and enable high availability and, in some
cases, load balancing and parallel processing
Beowulf Cluster:
Beowulf is an approach to building a supercomputer as a cluster of
commodity off-the-shelf personal computers, interconnected with a local
area network technology like Ethernet, and running programs written for
parallel processing.
Cluster Prerequisites:
1. Atleast Two Computers with a Linux Distribution installed in it.Make
sure that your system has GCC installed in it.
2. A network connection between them. If you have just two computers,
you can connect them using an ethernet wire. Make sure that IP
addresses are assigned to them. If you don’t have a router to assign IP,
you can statically assign them IP addresses, assign static IP addresses.

2. Steps Of Building a Beowulf Cluster:
The following steps are to be done for every node.
Step 1:Add Nodes-
First add the nodes.We can add the nodes in /etc/hosts file.We can use
the text editor to add node's IP address followed by its host name. For
example,
node0 10.1.1.1
node1 10.1.1.2
we will list the nodes using their host names. When required, the
program will use this hosts file to convert host names to corresponding
I.Ps.Like
10.255.2.x hostname1
10.255.2.y hostname2
10.255.2.z hostname3
Step 2:Create a user-
We shpuld create a new user for all nodes.we can create new user
through System->Administration->Users and Groups and give a
passward.We need to make same user all nodes not need to make same
passward to all nodes.
Step 3: Installing SSH-
Now download and install ssh-server in every node. Execute the
command sudo apt-get install opensshserver. Now we need to use
OpenSSH Server for enabling remote login. It should be mentioned that
remote tasks can be performed through telnet as well. But it does not

3. provide security for data flow. OpenSSH is a safer method for remote
login between PCs, hence it is adopted.
Step 4:Login to new user-
Now logout my current sesson and login as mpiuser.
Step 5: Generating SSH key-
After login as mpiuser open the terminal and type the ssh-keygen -t dsa.
This command will generate a new ssh key. It will be saved in the file
id_dsa and id_dsa.pub. The public key is saved in the file
~/.ssh/id_dsa.pub, while ~/.ssh/id_dsa is the private key. These files will
be saved in /home/mpiuser/.ssh/.
Step 6: Authorizing Keys-
A folder called .ssh will be created in your home directory. Its a hidden
folder. This folder will contain a file id_dsa.pub that contains your
public key. Now copy this key to another file called authorized_keys in
the same directory. Execute the command in the terminal cd
/home/mpiuser/.ssh; cat id_dsa.pub >>authorized_keys.If we donot do
this then we need to passward for every time for connect to others
computer.
Step 7:Download MPICH1-
Now download the MPICH1 from the web. Parallel computing system
MPICH is a robust and flexible implementation of the MPI (Message
Passing Interface). MPI is often used with parallel or distributed
computing projects. MPICH is a multi-platform, configurable system
(development, execution, libraries, etc) for MPI. It can achieve

4. parallelism using networked machines or using multitasking on a single
machine.
Step 8:Install MPICH1-
Make a folder in home folder then configure it and install it by executing
the command :
mkdir /home/mpiuser/mpich1
./configure --prefix=/home/mpiuser/mpich1
make
make install
Step 9:Editing files-
Open the file .bashrc in your home directory. If file does not exist, create
one. Copy the following code into that file
export PATH=/home/mpiuser/mpich1/bin:$PATH
export PATH
LD_LIBRARY_PATH="/home/mpiuser/mpich1/lib:$LD_LIBRARY_P
ATH"
export LD_LIBRARY_PATH
The two lines are used to append the address /home/mpiuser/mpich1/bin
which contains necessary executables of MPICH to the PATH variable.
The last two lines are used to append the address
/home/mpiuser/mpich1/lib which contains necessary libraries of MPICH
to the shared library path.
Step 10:Define the path to MPICH for SSH-

5. Give this command to add the bin directory of mpich1 to environment:
sudo echo /home/mpiuser/mpich1/bin >> /etc/environment
Now logout and login back into the user mpiuser.
Step 11:Edit machines.Linux-
In the folder mpich1, within the sub-directory share or util/machines/ a
file called machines.LINUX will be found. Open that file and add the
hostnames of all nodes except the home node ie. If you're editing the
machines.LINUX file of node0, then that file will contain host names of
all nodes except node0. By default MPICH executes a copy of the
program in the home node. The machines. sample contents of
machines.LINUX file:
hostname1
hostname2
Now cluster is ready .We can run any program through cluster.