Editing HPC High Processing Cluster in IIT DELHI (section)

==g. Installation of MPI ( Message Passing Interface)==


Initally LAM was used as MPI but the application Fluent doesn't work with this MPI so we installed MPICH2. The MPI mpich2 can be downloaded from http://www.mcs.anl.gov/research/projects/mpich2


1. Unpack the tar ﬁle.

 tar xfz mpich2.x.x.x.tar.gz


2. Choose an installation directory (the default is /usr/local/bin):

 mkdir /usr/local/mpich2/


 cd /mpich2


./configure –prefix=/usr/local/mpich2


make 

make install.


Set the enviroment variable for user “wolf” in /home/wolf/.bash_profile

Add following lines.


MPICH2=/usr/local/mpich2

PATH=$PATH:$HOME/bin:$MPICH2/bin


2.MPICH2, uses an external process manager for scalable startup of large MPI jobs. The default process manager is called MPD, which is a ring of daemons on the machines where you will run your MPI programs.


For security reasons, mpd looks in your home directory for a ﬁle named

.mpd.conf containing the line in home directory. So create this file as follows


cd $HOME

touch .mpd.conf

chmod 600 .mpd.conf


add a line 

<nowiki>secretword=<anysecretword></nowiki>


we used “fluentwolf” as secretword in our case.


3.The ﬁrst sanity check consists of bringing up a ring of one mpd on

the local machine, testing one mpd command, and bringing the “ring”

down.

 mpd &

 mpdtrace

 mpdallexit


The output of mpdtrace should be the hostname of the machine you

are running on. The mpdallexit causes the mpd daemon to exit


4.Now we will bring up a ring of mpd’s on a set of machines. Create a

ﬁle consisting of a list of machine names, one per line. Name this ﬁle

.mpd.hosts in home directory of user wolf. These hostnames will be used as targets for ssh so include full domain names if necessary. Check that you can reach these machines with ssh without entering a password. You can test by doing.


Ssh node1 –l wolf


# Start the daemons on (some of) the hosts in the ﬁle mpd.hosts 

mpdboot -n <nowiki><number to start> -f mpd.hosts</nowiki>


The number to start can be less than 1 + number of hosts in the ﬁle,but cannot be greater than 1 + the number of hosts in the ﬁle. One mpd is always started on the machine where mpdboot is run, and is counted in the number to start, whether or not it occurs in the ﬁle. By default, mpdboot will only start one mpd per machine even if the machine name appears in the hosts ﬁle multiple times. 


mpdboot -n 5 -f mpd.hosts


This will start the cluster.


mpdtrace


This command will show you the nodes in the cluster like below


Master_node

Node1

Node2