[X2Go-User] 25 user logon problem

[Mike Gabriel]

Hi Thomas,

On Sa 23 Mär 2013 16:28:28 CET Thomas Hanschke wrote:

> Hello everyone;
>
> I have set up a x2go terminal-server on ubuntu 12.04 in our school.
> There are 25 thinclients (wyse with windows7 embedded) in a classroom.
> The thinclients start with an openbox-session. So far it works fine, but
> there is a little problem:
>
> If more than 2 or 3 clients log on at exactly the same time, some of
> them stop at the black screen before the gray X2Go Logo appears.
> There is no error message. With a little timeshift of 2 or 3 seconds
> between the logons, there are no problems.
>
> Can anyone get a little help to solve this?

You experience a race condition where the server tries to allocate a  
display port per session and if two users log in very simulataneously,  
the second user won't get a valid display.

I am not sure if this can be avoided really reliably. However, instead  
of incrementing the X2GO_PORT by 1 in x2gostartagent (in case the  
probed port is not usable anymore) we could increment the X2GO_PORT by  
some random value (between 1 and 30). Then it could still be that two  
clients try to get the same DISPLAY port (in case two random calls  
deliver the same value), but the failing logins should reduce by far.

I Cc: our -dev list for further comment.

Mike



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