Monday Feb 18, 2008

Reaping (culling) Sun Ray sessions after a disconnect

Here's a simple way of conserving system resources under Solaris when you have a lot more users than Sun Rays. The idea is that if a user doesn't connect back to his session after a grace period, then his session is destroyed. Just make sure that your users know that their sessions have a limited time span, so they can save their work!

First, create a script called "reap-session" somewhere in your system, let's say /opt/SUNWut/scripts/reap-session. Make sure that you make it executable for everybody. The script, although very simple, is just there to save me some time :) in coding. It should be something like:

#!/bin/sh
GRACEPERIOD=7200      #That's two hours.
sleep $GRACEPERIOD
pkill Xsun

That's it for the little script.

Now, you need to invoke the script in the following manner, for those users whose sessions will be culled within GRACEPERIOD seconds - typically by executing in the .profile of the user:

/opt/SUNWut/bin/utaction -d /opt/SUNWut/scripts/reap-session -c "pkill reap-session " 1>/dev/null 2>&1 &

The way it operates is quite simple: as soon as the smartcard is pulled out, the timer is started via the disconnect utaction. If the user plugs his card back into the system before the timer goes off, then the connect utaction kills the timer and forgets the whole thing, to start afresh upon next pull of the card.

If, however, GRACEPERIOD elapses, then the timer goes off and the script kills the window manager for the user, and of course, with it, the whole session. Next time the user plugs his smartcard, he'll just see the login.

 

Friday Dec 07, 2007

Sydney Business and Travel Academy - A Cool and Heterogenous Sun Ray Setup

After running a little proof of concept (I spent less than half a day there) at the Sydney Business and Travel Academy (SBTA) I was surprised with the speed at which things moved there to make Sun Ray the desktop platform of choice. That's when it became obvious to me the amount of pain they were going through with their current setup of about 200 PCs and servers running Linux, LTSP and Windows. Enter Sun Ray, and all of a sudden, it's a fresh start for them - three servers for the whole joint, nothing to manage at the desktop nevermore, Windows using the Sun Ray Windows Connector for those who must, and only those who must, and mobility to become a given.


For students, there's little change, except the open source desktop they use on the new "workstations" is Solaris' JDS with StarOffice. Better yet, the students got locked down to printed smartcards with their student details on them, and access to the system only with a registered smartcard, hard tied to their login (no card sharing!) At the end of their tenure, their card is de-registered to revoke access forever, and so the card just becomes a memento.


But by far the most interesting thing about their deployment (let's face it, the above functionality is just standard functionality of the Sun Ray framework)  is how they physically locked the Sun Rays down to the desks, using a clever little bracket dreamed by the systems integrator and Sun partner, Noveix, and made by Argent . Check the pictures below for a simple and fantastic way of providing "locked-down" access to a workstation:






So, in the face of this, I decided to re-acronym SBTA: Special Bracket is Totally Awesome! And, monitors screwed to the desk too. Sweet!


In closing, this is what the same room looked like before - sorry I can't reproduce the noise!




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