[Beowulf] Remote console management

[Jamie Rollins]

Hi, Bruce (and others), 

I don't really understand why a standard ssh/telnet-accessible serial console
switch isn't just the answer to this?  ~$100/node doesn't seem like it's really
that much considering that it's probably only about 5% of the price per node, at
least for the system your talking about.  If the BIOS is accessible from the
serial line your good to go.  It's trivial to send a tty to the serial line
otherwise.  What more would you need?  It seem to me reliance on some other
piece of hardware for each node is adding more possible things that could break
into the equation.  The serial line is about as basic and low level as you can
get, and it's always there, and it provides everything that you could possibly
need.

> [1] if the BIOS can redirect console IO to a USB port, then use 
> USB-ethernet converters plus a cheap oversubscribed ethernet network and a 
> dedicated box to gather the output, or

I don't think this would work since the BIOS would have to be able to configure
the USB-ethernet converter correctly, right?

> [2] use the Linux netconsole driver to redirect console output to an 
> ethernet port, then gather this output (eg, kernel printk()s) with a 
> dedicated collection box.  The total cost of this option is one 
> inexpensive 24 or 48 ports switch in each rack, pluse one more switch to 
> concentrate those together.  This would cost under $20/node.

I'm not familiar with this.  Is it a TCP/IP based thing, or is it something
else, that just sends serial-type signals over the ethernet lines?  If it's
TCP/IP based, then you're ultimately just relying on the same system
infrastructure that you're needing to access the system by alternate ways to
fix, right?

jamie.