Linux Networking Question

[rbri]

I need some help setting up and configuring a group of Linux machines. Here is my issue.
I want to have one server on my LAN and also conecting to a private network switch. I will have 5 linux servers behind the switch on the private network. This will be used to run parellal solver jobs such as MCS, Fluent etc. I need to know how to configure the server and the clients networking wise. Thanks in advance for any help.

 

[JuJutsu]

Have two Ethernet cards in the servert that will be on both section.

JuJutsu - Jeff S.
Support Analyst

 

[jstreich]

Ah, a Beowulf Cluster!

Simple. Two cards, one to the private switch... No ipTable rules, allow passwordless rsh to these nodes using rhost files. External set up ipTables to only allow ssh from trusted hosts, all other ports should be blocked.

Pick a name for the control node. Name all the compute nodes in the cluster sequentially (i.e. node1, node2, node3). Put the list of all the names in /etc/hosts on all the machines, mapping their IPs . The sequential naming helps with scripting. You'll want scripts for adding users to all nodes, removing users from all nodes and shutingdown all nodes... They will be on the control node, and have the form:

#!/bin/bash
echo messner
useradd -m $1
for ((i = 1;i < 22;i++)); do
        echo tom$i
        rsh tom$i /usr/sbin/useradd -m $1;
done

Where messener is the control node, and the compute nodes are tom1 - tom22.

I am a system administrator for a cluster at my university. I can post more information if you need me to. You may also want to search for RGB's guide to building a cluster, and search the beowulf list (

http://www.beowulf.org

).


[plug=shameless]

http://game-master.us/phpx-3.4.0/

[/plug]

 

[rbri]

I was not going to create a beowulf cluster...Just group of nodes running linux WS 3.4 using Platform LSF for job scheduling.

 

[jstreich]

Platform LSF is a grid style program, the resulting network is thusly classifiable as a Beowulf Cluster.

Beowulf Clusters are scalable performance clusters based on commodity hardware, on a private system network, with open source software (Linux) infrastructure. The designer can improve performance proportionally with added machines. The commodity hardware can be any of a number of mass-market, stand-alone compute nodes as simple as two networked computers each running Linux and sharing a file system or as complex as 1024 nodes with a high-speed, low-latency network.

http://beowulf.org/

In any case, my advise still stands.
Use static, sequential ips and naming convention to make life easier... For instance, you hosts file should look something like this:

192.168.42.100  control
192.168.42.1    node1
192.168.42.2    node2
192.168.42.3    node3

If you don't have a /etc/hosts file, you'll need to run a DNS server which will take bandwidth -- it won't be that much, but it's just another hoop that you don't need (unless the compute nodes need to see the outside world).


If you consider it a cluster or not the control node/server still must be set up with the following things in mind:
- Does the outside ethernet have a static IP, or is it assigned by DHCP?
On RHEL WS, this is set for each network card in /etc/sysconfig/network-scripts/ ...
- Which interface is outside and which is inside? Make sure to write this down for future reference.
- Do the nodes need to see the outside network at all? If it does, you'll need to setup some form of forwarding -- if not, then alls well.
- Will you be using NFS/SAMBA to move files across the nodes, or will you use ftp/sftp/rcp/scp ... ?
- How secure will it need to be on each end?
In most cases you'll want the server (even just a webserver) will block all ports not in use (using iptables) -- espcially ping -- and may even restrict what trusted sources are allowed access to ports you are serving on. You'll need to tight security to the outside world. In the private network side, however, you'll need to minimize the security so that parallel software doesn't get run into firewall, unexpected permission problems or such.

rgb's how-to would be a great refference for you, even if your not building a Earth Simulator 3.

[plug=shameless]

http://game-master.us/phpx-3.4.0/

[/plug]