/etc/hosts file for machines need to comment out the line with the 127.0.1.1

"otherwise other hosts will try to connect to localhost when they try to reach the master node" -- https://help.ubuntu.com/community/MpichCluster

If /etc/hosts is setup this way it can be cloned to the other nodes.

127.0.0.1	localhost
#127.0.1.1	OptiPlex-790

192.168.1.1     netgear-router
192.168.1.2     renee-pc
192.168.1.4     reneecomputer
192.168.1.5     Precision-WorkStation-530-MT
192.168.1.9     erick-laptop
192.168.1.10    ubuntuserver
192.168.1.11    ubuntuserver-c
192.168.1.17    raspberrypi
192.168.1.18    OptiPlex-790
192.168.1.19    Compaq-Presario
192.168.1.50    dlink-router

After fiddling with /etc/hosts, restart networking...

sudo service network-manager restart



Adding mpiu user, make owner of mirror, set up shell
Run this from your user, all of them are sudo commands.

sudo useradd -m -d /mirror -u 1005 mpiu <--- 999 would be a better choice, it won't show up in the login screen!

Make the passwords the same on all nodes...
sudo passwd mpiu

Setup ownership...
sudo chown mpiu /mirror
sudo chgrp mpiu /mirror

Change the shell, need to be outside of user mpiu, this could be rolled into adduser I am certain.
sudo chsh -s /bin/bash mpiu


Executing bash in the mpiu will bring up bash.
which bash shows the path.

This will be needed later but needs to happen from a sudoer account now.
install keychain 
sudo apt-get install keychain


Change to the mpiu user, in the /mirror home dir...
su - mpiu

Run on main node, no need to run on all other nodes as the dir is mirrored...

mkdir .ssh
cd .ssh
ssh­-keygen ­-t rsa 


cat id_rsa.pub >> authorized_keys



add code to .bashrc

if type keychain >/dev/null 2>/dev/null; then
  keychain --nogui -q /mirror/.ssh/id_rsa
  [ -f ~/.keychain/${HOSTNAME}-sh ] && . ~/.keychain/${HOSTNAME}-sh
  [ -f ~/.keychain/${HOSTNAME}-sh-gpg ] && . ~/.keychain/${HOSTNAME}-sh-gpg
fi




On 2nd node
make sure hosts file has all the names in it!

sudo mount Optiplex-790:/mirror /mirror

run commands from

adding-users.sh  <-- needs work

MAKE PASSWORDS THE SAME, this way you can SSH to the other nodes without password.
ssh nodename should auto-login! Check this manually.



Primary node
Needed this...not sure what for. Was trying to get this thing going.

erick@OptiPlex-790 /mirror $ sudo apt-get install libmpich-dev



IMPORTANT
from (https://www-users.cs.york.ac.uk/~mjf/pi_cluster/src/Building_a_simple_Beowulf_cluster.html)



The firewall is by default enabled on Ubuntu. The firewall will block access when a client tries to access an NFS shared directory. So you need to add a rule with UFW (a tool for managing the firewall) to allow access from a specific subnet. If the IP addresses in your network have the format 192.168.1.*, then 192.168.1.0 is the subnet. Run the following command to allow incoming access from a specific subnet,

master:~$ sudo ufw allow from 192.168.1.0/24


Test the setup...
mpiexec -f machinefile -n <number> hostname



Download examples by getting the tarball for mpich...
http://www.mpich.org/downloads/

pull out the doc and examples folders
It is easy to make a chmodded 777 Public folder in /mirror in order to dump files from other users.