[FreeNX-kNX] Load Balancing leaving unconnectable sessions

[Matthew Richardson]

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.

We currently have the number of sessions limited for each user to 1, so
that we can flag up when these sessions are sticking, but I'm not sure
beyond that where to start with diagnosing the issue. (I've attached an
example log of the kind that we tend to see when this problem occurs).
I've also attached our standard config file.

Can anyone point me in the right direction for diagnosing this issue?
If there any other information that would be useful to provide let me
know and I'll provide more debugging information.

Thanks,

Matthew


##############################

NX> 203 NXSSH running with pid: 18775
NX> 285 Enabling check on switch command
NX> 285 Enabling skip of SSH config files
NX> 285 Setting the preferred NX options
NX> 200 Connected to address: x.x.x.x on port: 22
NX> 202 Authenticating user: nx
NX> 208 Using auth method: publickey
HELLO NXSERVER - Version 3.2.0-73 OS (GPL, using backend: not detected)
NX> 105 hello NXCLIENT - Version 3.2.0
NX> 134 Accepted protocol: 3.2.0
NX> 105 SET SHELL_MODE SHELL
NX> 105 SET AUTH_MODE PASSWORD
NX> 105 login
NX> 101 User: josoap
NX> 102 Password:
NX> 103 Welcome to: server.example.com user: josoap
NX> 105 listsession --user="josoap" --status="suspended,running"
--geometry="2560x1024x24+render" --type="unix-gnome"
NX> 127 Sessions list of user 'josoap' for reconnect:

Display Type             Session ID                       Options  Depth
Screen         Status      Session Name
------- ---------------- -------------------------------- -------- -----
-------------- ----------- ------------------------------
1012    unix-gnome         A12D4DBF3BDE66C0A388F61E1CDBFD3B -RD--PSA    24
2560x1024      Suspended     SEE NX


NX> 147 Server capacity: reached for user: josoap
NX> 105 restoresession  --link="adsl" --backingstore="1" --encryption="1"
--cache="16M" --images="64M" --shmem="1" --shpix="1" --strict="0"
--composite="1" --media="0" --session="SEE NX" --type="unix-gnome"
--geometry="2560x1024" --client="linux" --keyboard="pc105/gb"
--id="A12D4DBF3BDE66C0A388F61E1CDBFD3B"

NX> 1000 NXNODE - Version 3.2.0-73 OS (GPL, using backend: not detected)
NX> 700 Session id: keith.see.ed.ac.uk-1056-B8B29E382CEF9555C4893C270701ADE2
NX> 705 Session display: 1056
NX> 703 Session type: unix-gnome
NX> 701 Proxy cookie: 2ef39a70467f1e82d42a0f6431193841
NX> 702 Proxy IP: x.x.x.x
NX> 706 Agent cookie: 2ef39a70467f1e82d42a0f6431193841
NX> 704 Session cache: unix-gnome
NX> 707 SSL tunneling: 1
NX> 1004 Error: Session did not start.
NX> 596 Session resume failed.
NX> 999 Bye
NX> 280 Exiting on signal: 15

##############################

/etc/nxserver/node.conf:

ENABLE_FORCE_ENCRYPTION="1"
SESSION_LIMIT="200"
DISPLAY_LIMIT="200"
DISPLAY_BASE="1001"
ENABLE_USESSION="1"
AGENT_STARTUP_TIMEOUT="20"
ENABLE_AUTORECONNECT=0
ENABLE_PULLDOWN_MENU=1
ENABLE_SHOW_RUNNING_SESSIONS=1

SESSION_USER_LIMIT="1"
COMMAND_START_KDE=xfce4-session
COMMAND_START_GNOME=xfce4-session
COMMAND_START_CDE=xfce4-session

#On the master only:
LOAD_BALANCE_ALGORITHM="random"
LOAD_BALANCE_SERVERS="server1, server2, etc...."

##############################

-- 

The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.


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