[K12OSN] Fullscreen localapp without a window manager

[Jeff Siddall]

I found a simple method to run fullscreen localapps without a window
manager on a thin client.  I use this setup for kiosks/appliances that
don't have a keyboard/mouse/user.  It has the major benefits of being
extremely light on server resources while also preventing typical
desktop environment annoyances (like pop up windows) which could cover
the fullscreen app I really want to see.

I am running LTSP5 on Fedora 13.  This procedure should work on other
Fedora releases (and maybe other LTSP releases too) but YMMV.

I have successfully tested this with ooimpress and vlc, though firefox
did not go fullscreen, even with rkiosk installed.

The easiest way to begin is to run "switchdesk twm" (or whatever WM you
choose, it doesn't matter) as the desired user.  This will create a
.Xclients and a .Xclients-default file in the user's home directory.
Modify the .Xclients-default file so it contains only one line:

exec <full path to script on server>

Where <full path to script on server> is the script you want to run when
the user logs in (ex: /usr/local/bin/vlc-ltsp-localapps.sh)

The script should contain the ltsp-localapp command you want run on one
line (ex: /usr/bin/ltsp-localapps vlc -f --deinterlace-mode=bob
udp://@239.255.12.42) followed by:

sleep 999d

on the next line.  The long sleep is required to prevent the script from
returning anytime soon.  Since ltsp-localapps returns immediately after
spawning the localapp the script would normally exit immediately also,
which would cause X to exit immediately also.

I use this in combination with:

LDM_AUTOLOGIN = True
CONFIGURE_X = True
X_MONITOR_OPTION_01 = "\"DPMS\" \"false\""
LDM_USERNAME = user
LDM_PASSWORD = password

in the lts.conf so the client immediately launches the fullscreen
localapp on bootup.

Someone with some desire could certainly create a much nicer set of
scripts that could create a PID file in the user home directory on the
client which the .Xclients-defaults script on the server could watch and
then exit to restart X if the local-app ever died.  In the simple setup
I described above if the localapp dies it will just show a black screen
for the next 3 years or so!  I'll just hit the reset button when that
happens.

Jeff