[FreeNX-kNX] Load Balancing leaving unconnectable sessions

[Matthew Richardson]

Mario Becroft wrote:
> Matthew Richardson <M.Richardson at ed.ac.uk> writes:
> 
>> We're running an nx pool with around 75 computers in it, with a single
>> master which all users connect to.
>>
>> We seem be be regularly hitting the problem that when a user disconnects
>> from a session, it somehow becomes disconnected from the master, and
>> when then user tries to connect again they can't reconnect to that
>> session.  This is a fairly regular occurrence, with possibly around 1 in
>> 20 sessions sticking this way.
> 
> When a session becomes stuck in this way, please check whether the
> user's nxagent is still running. If so, then the session is still there,
> just inaccessible.

It looks like we're currently using nx 3.2.0-8, so I'll try upgrading
this to the latest version from nomachine to see if that makes any
difference.

I've just reviewed another stuck session - here are the details of the
processes involved, in case its a more general problem that someone can
diagnose (I'll report again after the upgrade if it continues to happen):

nxmaster:

nx       18394 18391  0 Aug12 ?        00:00:00 /usr/bin/expect
/usr/bin/nxnode-login -- ssh username 22 /usr/bin/nxnode --startsession

nx       18396 18394  0 Aug12 pts/4    00:00:00 ssh -2 -x -l username
server.example.com -o NumberOfPasswordPrompts 1 -p 22 /usr/bin/nxnode
--startsession

(Around 6 of these 'pairs' - all for the same user, who had tried and
failed repeatedly to resume the session, but all with slightly different
time stamps).

nxslave:

(I've cut out all the window manager processes and children which are
still running)

tcsh -c /usr/bin/nxnode --startsession
username     31084 31046  0 Aug12 ?        00:00:00     /bin/bash
/usr/bin/nxnode --startsession
username     31309 31084  0 Aug12 ?        00:00:00       /bin/bash
/usr/bin/nxnode --startsession
username     31310 31309  0 Aug12 ?        00:00:00         /bin/bash
/usr/bin/nxnode --startsession
username     31316 31310 67 Aug12 ?        18:37:39
/usr/lib/NX/nxagent -persistent -D -name NX -
username at server.example.com:1018 - username (GPL Edition) -option
/tmp/.nx-username/.nx/C-server.example.com-1018-5D8D8CCCE2EBDD610FCB711745CC444C/options
-keyboard pc102/gb -geometry 1024x900 -nolisten tcp :1018
username     31311 31309  0 Aug12 ?        00:00:00         tee
/tmp/.nx-username/.nx/C-server.example.com-1018-5D8D8CCCE2EBDD610FCB711745CC444C/session
username     31314 31309  0 Aug12 ?        00:00:00         /bin/bash
/usr/bin/nxnode --startsession
username     31312 31084  0 Aug12 ?        00:00:00       /bin/bash
/usr/bin/nxnode --startsession

username     12694     1  0 09:04 ?        00:00:00   tcsh -c
/usr/bin/nxnode --resumesession
username     12727 12694  0 09:04 ?        00:00:00     /bin/bash
/usr/bin/nxnode --resumesession
username     12954 12727  0 09:04 ?        00:00:00       tail -n1 -f
/tmp/.nx-username/.nx/C-server.example.com-1018-5D8D8CCCE2EBDD610FCB711745CC444C/session
username     12955 12727  0 09:04 ?        00:00:00       /bin/bash
/usr/bin/nxnode --resumesession
username     24562     1  0 15:15 ?        00:00:00   tcsh -c
/usr/bin/nxnode --resumesession
username     24598 24562  0 15:15 ?        00:00:00     /bin/bash
/usr/bin/nxnode --resumesession
username     24824 24598  0 15:15 ?        00:00:00       tail -n1 -f
/tmp/.nx-username/.nx/C-server.example.com-1018-5D8D8CCCE2EBDD610FCB711745CC444C/session
username     24825 24598  0 15:15 ?        00:00:00       /bin/bash
/usr/bin/nxnode --resumesession
username     24861     1  0 15:15 ?        00:00:00   tcsh -c
/usr/bin/nxnode --resumesession
username     24888 24861  0 15:15 ?        00:00:00     /bin/bash
/usr/bin/nxnode --resumesession
username     25114 24888  0 15:15 ?        00:00:00       tail -n1 -f
/tmp/.nx-username/.nx/C-server.example.com-1018-5D8D8CCCE2EBDD610FCB711745CC444C/session
username     25115 24888  0 15:15 ?        00:00:00       /bin/bash
/usr/bin/nxnode --resumesession



There's only one nxagent on that system for that user (but there are
others for other user's sessions, if that matters?)

Hope this is useful for diagnosis - let me know if you need any other
info...

Thanks,

Matthew


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