[auton-users] Remote GUI to computing nodes available

[predragp at andrew.cmu.edu]

Dear Autons,

This is to let you know that Remote GUI access to selected
newly installed computing nodes (LOV3, LOV4, and LOU1) is now
available from within Lab's internal network (VPN-desktops)
and from outside of Lab. NAVY cluster is also accessible. but
that is not the topic of this message

Access is available via three different servers: FreeNX, X2Go, and VNC.
In an ideal world I would have enabled only NX X server (compresses ssh -Y)
but the open source version FreeNX didn't quite work for me as well as
proprietary which unfortunately allows only for two concurrent session.
I have not spent any time trouble shooting this but it looks that it
might have to do with the propriety client I was using to connect.


X2Go (another compressed ssh -Y) works like a charm but I have hear
of mixed review for clients

http://wiki.x2go.org/doku.php/doc:installation:x2goclient

I strongly recommend only lunching an xterm and then starting
a MATLAB or whatever you need to use with the FULL path to binaries.
This is well tested!


Finally I also installed tigervnc-server which of course uses VNC
protocol and uses ports 5900 and above. Using VNC is not hard but
requires some reading
http://math.arizona.edu/support/account/remotedesktop/vnc.html
This is also well tested!


I expect that an immediate reaction on my claim that above services
are available outside of Auton Lab netwrok from many of you will be "What in
the world is he talking about when we all know that the Lab is firewalled
and on the top of it computing nodes have only internal DNS records".
That is indeed true and a proper access from outside the lab will require
VPN credentials which I will provide as soon as I rebuild our VPN gateway.
However I know that many of you are well versatile in ssh wizardry so am I.

In what follows I will describe how to access LOU1 via VNC session.
To bypass AutonLab firewall log from your home computer via one of
ssh gateways to one of the computing nodes you would like to have GUI access.
Then do reverse ssh proxy to bypass firewall. For example to have my
VNC session on LOU1 available at home on I did this

predrag at lou1 ~ $ ssh -R 5901:localhost:5901 bagdala2.dyndns.org

Where bagdala2.dyndns.org is my home machine which has dynamic IP but
it is accessible via DynDNS services. Then just open vncviewer and
type localhost:5901 as a destination server and your normal Auton Lab
password. Miraculously you will be taken to LOU1 via GUI.

If you are trying to do this with SSH make sure you use non privileged
port on your home computer.

Please sent me a private e-mail if you want to learn more about this
or stop by my office after the break.

Enjoy,
Predrag Punosevac

P.S. I tested MATLAB 2013b on LOU1 and licensing manager works as expected.