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After exhaustively searching on Google and other locations, I still need some direction or primer on setting up the network I'm aiming for.

I have a cluster of machines networked via SSH using external static IPs. What I want to do is localise the network and only have one external node that all the other machines route through to access the Internet (and conversely, externally access the other nodes via SSH through this one machine).

This is set up on a university network, so we don't have an internal network router, only a switch (Netgear GS748T). Is it possible to use the switch to set up a local network (using say 192.168.x.x addressing) and then route through one machine to the external network? And if so, how is this set up and managed? The main reason for the switch is because we're entirely dependent on the external network being up for parallelisation -- if the university network drops for any reason, we lose the cluster connectivity.

Not being a typical set up, I've found it difficult to find guides to get off the ground. As such, any help or suggestions of where to direct my search would be appreciated.

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1 Answer 1

I'm fairly new to this myself, but hopefully this helps:

If you put two NICs in your master node, you can have one of those connected to the outside world and then connect the other one to the switch which would connect to all of your compute nodes. You would want to run DCHP to serve out IPs to all of the nodes and DNS so that people won't have to know the IPs of the nodes to ssh/rsh to them. Dnsmasq is the easiest way to get these two services running.

In /etc/network/interfaces add something like:

# The primary network interface
auto eth0
iface eth0 inet dhcp

# The inside network interface - To the Nodes
auto eth1
iface eth1 inet static
address 192.168.0.254 #(I set the master to 254 so node1 can be .1, etc)
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255

In /etc/dnsmasq.conf make sure you define interface=eth1 (the inside network) so you're not trying to serve IPs to the outside world.

In /etc/hosts add the lines for your compute nodes:

...
192.168.0.1    node1.<domain>   node1
192.168.0.2    node2.<domain>   node2
...
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