|00:23||ddave7 has left IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz, Quit: Miranda IM! Smaller, Faster, Easier. http://miranda-im.org)|
|00:43||toscalix has left IRC (firstname.lastname@example.org, Read error: Connection reset by peer)|
|01:13||eddytv has joined IRC (email@example.com)|
Anybody around who'd like to help me with an LTSP issue? I upgraded my Ubuntu server to 12.04 today, and now my diskless clients won't boot because of a problem with 'nbd'
From what I can tell, 'nbd' was previously configured to run from inetd on port 2000...
and it seems LTSP now expects to use a "named port", and possibly have nbd running NOT from inetd?
|01:49||Phantomas has joined IRC (Phantomas!~Phantomas@unaffiliated/phantomas)|
|01:52||Phantomas has left IRC (Phantomas!~Phantomas@unaffiliated/phantomas)|
Any there any docs on setting up a COW overlay for LTSP diskless clients via NFS?
|05:13||bobby_C has joined IRC (bobby_Cfirstname.lastname@example.org)|
|05:16||komunista has joined IRC (email@example.com)|
eddytv, did you upgrade chroot as well?
|05:30||alkisg has joined IRC (alkisg!~alkisg@ubuntu/member/alkisg)|
eddytv, in 12.04 NBD runs as a standalone daemon, not from inetd. Type 'service nbd-server status' to see if it's started, and 'service nbd-server start' to start it.
|07:00||bobby_C has left IRC (bobby_Cfirstname.lastname@example.org, Ping timeout: 272 seconds)|
|07:43||epoptes_user2 has joined IRC (epoptes_user2!c3616e6c@gateway/web/freenode/ip.220.127.116.11)|
|07:43||epoptes_user2 has left IRC (epoptes_user2!c3616e6c@gateway/web/freenode/ip.18.104.22.168)|
|07:58||bobby_C has joined IRC (bobby_Cemail@example.com)|
alkisg: i'm working on the source hierarchy for the wiki now, and i'm not sure about the contents of some of the server dirs
what should be in /server/configs /server/docs /server/services /server/xinetd.d ? Can't they be merged?
it seems like /server/services can be merged with that one
and the xinetd.d stuff also
xinetd and services seem like fedora to me
Maybe they should go under distro-specific dirs
i also use the nbdswapd
You use xinetd?
for nbdswapd only
OK, debian/ubuntu use inetd instead
So I guess something like an etc/ directory with those would be better
I think that in the next BTS the code directory layout should be discussed
Maybe we could put all those in examples too, yeah
And have the packages that need them ship them in the appropriate service place too
a /server/doc/examples/nbdswap-xinetd.d would be in line with recent changes
|08:35||daya has joined IRC (daya!~daya@unaffiliated/daya)|
|08:38||daya has left IRC (daya!~daya@unaffiliated/daya, Read error: Connection reset by peer)|
|08:52||mikkel has joined IRC (firstname.lastname@example.org)|
|08:59||daya has joined IRC (daya!~daya@unaffiliated/daya)|
|09:06||ddave7 has joined IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz)|
|09:19||Steve_The_Pirate has joined IRC (Steve_The_Pirate!~Gary@cpc16-haye17-2-0-cust169.haye.cable.virginmedia.com)|
|10:38||ogra_ has left IRC (email@example.com, Ping timeout: 252 seconds)|
|10:59||ddave7 has left IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz, Quit: Miranda IM! Smaller, Faster, Easier. http://miranda-im.org)|
|11:03||ddave7 has joined IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz)|
|11:06||Trixboxer has joined IRC (Trixboxer!~Trixboxer@22.214.171.124)|
|11:17||daya has left IRC (daya!~daya@unaffiliated/daya, Ping timeout: 272 seconds)|
muppis: I didn't "upgrade" the chroot after moving to 12.04, I mv'd /opt/ltsp to /opt/ltsp-save, and then ran ltsp-built-client. Unfortunately, there is no longer a "--mythbuntu" option, and that's why I think I'm screwed. I didn't know that option was gone before upgrading.
eddytv, did you test that what Hyperbyte said?
Hyperbyte: I figured out that 'nbd-server' needed to run as a service, so I commented out the lines for ports 9571 (ldminfod), 9572 (nbdswapd) and 2000 (nbdrootd) from 'ineted' and started nbd-server... after adjust some other files, I *did* get the diskless clients to at least start booting
However, they booted to an 'ldm' login screen
|11:36||ddave71861 has joined IRC (ddave71861!~Miranda@ip-94-113-119-192.net.upcbroadband.cz)|
|11:36||ddave7 has left IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz, Read error: Connection reset by peer)|
I assume there's some way to "autologin" a user (ala 'mythtv'), but while researching that, I found a much bigger issue, and that is the apparent lack of an NFS-based copy-on-write for the root filesystem (/) that the diskless clients rely on :(
|11:38||toscalix has joined IRC (firstname.lastname@example.org)|
eddytv: you can probably just create a fat chroot and install the mythbuntu packages inside it
The mythbuntu ltsp-build-client plugin was unmaintained, it didn't work anymore
Apparently one of the things the now-gone '--mythbuntu' option did was set up an NFS-based overlay, which stored any changes from the base .img in /var/cache/mythbuntu-diskless/overlay/HOSTNAME
Such things should be upstream, not in an unmaintained distro postinst script
alkisg: I did create a "fat" /opt/ltsp and it did install the mythbuntu packages
Why would one need an overlay for mythtv?
It's the lack of the NFS overlay that is the issue now. Each of the diskless clients has a tweaked xorg.conf, asound.conf, etc. that is specific to its hardware/display/etc.
...mythbuntu or however it's called?
There are standard ltsp ways to provide custom xorg.confs
No need to invent new ones
What do they need in asound.conf?
Every diskless client is different. Some use HDMI for audio, some use analog, etc.
There are lts.conf parameters for xorg and audio
alkisg: lts.conf: http://manpages.ubuntu.com/lts.conf
E.g. you can just a custom resolution by just specifying XRANDR_MODE_0=1024x768
Or you can select a custom xorg.conf with X_CONF
There shouldn't be need for different chroots just to finetune some hardware differences
If you find out that you need something that's not covered by upstream code, then you should file a feature request bug
The NFS overlay allowed this to be adjusted very easily -- you could tweak files on the diskless clients "like normal", and it would copy-on-write to the NFS overlay, no tweaking on the "backend" for all the files. Plus, it also worked great for things like /var/log
An NFS (or other filesystem) overlay can be handy, but the developer should have pushed the code upstream and should be willing to maintain it
I don't even know who developed that plugin, the code never came upstream
asound.state is another good example -- it's a "state" file for each diskless client, and can change
There are volume settings in lts.conf, and per user volume settings too
Anyway, long story short: I'm in a heap of trouble with the family because nobody can watch TV :(
Just try to cover your needs by using upstream code, and see what's missing so that you can report it
NFS overlays can be dangerous, they can break things on upgrades
Saving/restoring files should be a monitored process
I just wish the mythbuntu folks had made it very obvious that moving to 'precise' would break any installs that use diskless frontends
I had no clue that that --mythbuntu option was so "unsupported"
Indeed, you're right on that complain
I tried reverting back to my original /opt/ltsp, but no joy there either... I set up nbd-server with 'oldstyle = true' and told it to listen on port 2000, re-ran ltsp-update-kernels to populate /var/lib/tftpboot/ltsp/amd64 with "the right stuff" and I just get a bunch of nbd I/O errors on the clients
So I assume there is some compatibilty issue with the (old) nbd code that gets run on the clients and the new nbd code running on the server
|11:55||ddave71861 is now known as dsorf|
|11:55||dsorf has left IRC (dsorf!~Miranda@ip-94-113-119-192.net.upcbroadband.cz, Quit: Miranda IM! Smaller, Faster, Easier. http://miranda-im.org)|
eddytv: which version did you use previously? 10.04? 11.10?
|11:56||ddave7 has joined IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz)|
I was on 11.04 (natty). I upgraded to 11.10 and then 12.04 because I wanted to get to the LTS level.
eddytv: so your chroot is from 11.10?
no, 11.04. I did the upgrade to 11.10/12.04 back-to-back.
(in which ubuntu version it was genenated)
Try putting nbd-proxy=false in pxelinux.cfg/default
alkisg: nbd-proxy: Ubuntu 10.04 and 10.10 use a wrapper called nbd-proxy, which is causing networking problems for some people. See https://bugs.launchpad.net/ltsp/+bug/589034. It's been disabled by default in 11.04, see http://bazaar.launchpad.net/~ltsp-upstream/ltsp/ltsp-trunk/revision/1803
Hmm ok then, not there in 11.04
You can try removing /etc/nbd-server/conf.d/config and putting nbd-server in /etc/inetd.conf like it was in 11.04
And you'll also need appropriate parameters in /var/lib/tftpboot/ltsp/amd64/pxelinux.cfg/default
I did try that originally...
But all those are temporary solutions, the correct one would be to move to a new chroot and see what's missing and how it can be fixed, e.g. move to X_* commands in lts.conf etc
and pxelinux.cfg/default has 'autoconf=dhcp nbdport=2000'
Other than the X and sound issues, did the mythbuntu desktop work for you as expected?
I didn't get that far; 'ldm' came up and there are no keyboards on the clients... I was going to try setting up autologin, but then I stumbled across the overlay issue and thought that was a bigger issue
It shouldn't be. Autologin is easy, just a couple of lines in lts.conf.
Sorry, was referring to the overlay thing being the bigger issue
Yup, me too.
It shouldn't be an issue.
What other problems do you want to solve with an overlay?
You mentioned X, which there's support for in lts.conf, and asound.conf, and while that's not saved/restored on boot, you can set volume levels from lts.conf, and your DE can save/restore the user sound settings on login/logout
OK. Well it's an issue currently because files like xorg.conf, asound.conf and asound.state are all "overlaid"...
|12:06||ddave7 has left IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz, Read error: Connection reset by peer)|
|12:06||ddave71861 has joined IRC (ddave71861!~Miranda@ip-94-113-119-192.net.upcbroadband.cz)|
|12:07||ddave71861 is now known as dsorf|
As I said, you can have custom xorg.conf files from lts.conf. And you probably don't even need them.
|12:07||dsorf has left IRC (dsorf!~Miranda@ip-94-113-119-192.net.upcbroadband.cz, Client Quit)|
You can customize many xorg options without xorg.conf nowadays
Screen resolution, mirroring etc
|12:07||ddave7 has joined IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz)|
What about log files in /var/log? Are they maintained, or just stored on a tmpfs?
lts.conf supports remote logging, if you need it
So that client log files go on the server
Looking through the lts.conf page you linked to, I see that for syslog. mythtv logs directly to /var/log/mythtv/*, so remote syslogging probably won't help in that regard. But that's not a showstopper. If I can get ldm autologin working, and set up lts.conf with whatever options I need, maybe I can get the front-ends functional enough.
Although I just thought of another issue, the lircd.conf (for remote control) is different on each client as well since not all the remotes are the same.
The LTSP way would be to make a script that reads its environment for lts.conf variables, and writes lircd.conf on client boot
It's very easy, see the examples in $chroot/usr/share/ltsp/init-ltsp.d
OK. Thanks alkisg! At least you've give me a ray of hope. I was thinking I was really screwed; now with a little luck and some hacking at lts.conf I might be able to get this going again. Appreciate your insight.
You're welcome, feel free to file bugs for things you think that will interest others, e.g. a lircd.conf script
OK. Will do. Thanks again!
One other question I had: is there an LTSP-supported way to disable all the Ubuntu auto-update checks / notifications on the clients/
They are automatically disabled for gnome and for some parts in KDE
E.g. $chroot/usr/share/ltsp/init-ltsp.d/50-disable-cronjobs, $chroot//usr/share/ltsp/init-ltsp.d/50-rm-session-services
There's an RM_SESSION_SERVICES list there, you can add to it from lts.conf
OK... thanks a bunch.
|12:20||alkisg has left IRC (alkisg!~alkisg@ubuntu/member/alkisg, Quit: Leaving.)|
|13:00||ddave7 has left IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz, Ping timeout: 245 seconds)|
|13:08||ddave7 has joined IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz)|
|13:20||risca has left IRC (email@example.com, Quit: Lämnar)|
|14:05||BigBear has joined IRC (BigBear!4dfb53b7@gateway/web/freenode/ip.126.96.36.199)|
hi, quick ltsp newbie question: what thin client hardware works with Ubuntu+LTSP ??
i was looking at some HP thin clients (5520, 5530) but i don't know if those will work with LTSP ??
BigBear, generally speaking, if it works with Ubuntu and can do PXE boot, it will work.
oke that helps, thanks. any experience with HP thin clients ?
Only one. I thought it sucked pretty badly for the money I paid for it.
But it booted LTSP fine...
i have on old one, bought secondhand, but working like a charm
i was looking at some secondhand HP thin clients 5520, 5530... for only €19,- or € 29,- a piece
well, i guess i'll just buy one and see if and how it works and then buy more
€ 19,- isn't the end of the world... ;)
i got a t5710
|14:17||alkisg has joined IRC (alkisg!~alkisg@ubuntu/member/alkisg)|
ok thanks guys i'll just try some of those...
|14:18||toscalix has left IRC (firstname.lastname@example.org, Read error: Connection reset by peer)|
so ... we are 2 weeks away from deployment of an LTSP project and I get an email from the customer with this link in it
I see disklessworkstations.com carries HP stuff ... is there a high likelihood that this model will be available upon release?
BigBear: I have an HP T5000, it boots LTSP and works for basic office work but that's it, don't expect full screen video or localapps to work
I am hoping they will go with the LTSP Term 1720's ... double the ram ... intel proc ... better video ... available for sale now ... etc. But this customer loses all perspective on reality anytime PoE is mentioned.
is that t410 a true zero client? i don't think ltsp will run on those
on a zero client nothing is done locally right? only the viewport is pushed toward it?
|14:36||BigBear has left IRC (BigBear!4dfb53b7@gateway/web/freenode/ip.188.8.131.52)|
it says pxe
and we would swtich to vmware view if necessary
it seems a bit of a headache to remove one wire from each desk
and you have to add that wire back in to get better than 10/100
especially since we are 2 weeks from deployment and the things are not on sale yet
|14:39||Phantomas has joined IRC (Phantomas!~Phantomas@unaffiliated/phantomas)|
you'd have to use a distro which supports arm thin clients
don't know if ubuntu or debian support arm
wafflecone, I have LTSP Term 1720's at my work.
|14:47||highvolt1ge has joined IRC (email@example.com)|
we have a LTSP Term 1220 that we use for testing
it is just perfect
but somebody always has to have a better idea at the last minute
|14:49||highvoltage has left IRC (highvoltage!~highvolta@ubuntu/member/highvoltage, Read error: Connection reset by peer)|
The 1720 required some tweaking to work with dual screens, but DLWS released a fix for that... and I'm not happy with the sound quality the onboard soundcard produces, but we're using USB headsets now, so... I really like the way they look though, and the specs they carry... plus they're quite robustly built I think.
|14:52||highvolt1ge has left IRC (firstname.lastname@example.org, Ping timeout: 260 seconds)|
|14:52||highvoltage has joined IRC (highvoltage!~highvolta@ubuntu/member/highvoltage)|
hyberbyte. It is a shame they don't have the VESA monitor mounts for them
|15:14||bobby_C has left IRC (bobby_Cemail@example.com, Ping timeout: 272 seconds)|
stgraber, knipwim, cyberorg: instead of hardcoding BOOTPROMPT_OPTIONS in the code, I think it would be better if they were shipped as a configuration file in $chroot/etc/ltsp/update-kernels.conf as part of the ltsp-client package, would you mind if that was a requirement? Example content:
NBD_CMDLINE='ro initrd=$INITRD root=/dev/nbd0 init=/sbin/init-ltsp nbdroot=$SERVER:$PORT$NBD_NAME'
NFS_CMDLINE='ro initrd=$INITRD root=/dev/nfs init=/sbin/init-ltsp'
That way an e.g. Ubuntu LTSP server can properly identify a Gentoo chroot cmdline, and also different ltsp-client package versions can ship with different command lines and the user can more easily see where he should edit the cmdlines.
The variables are evaluated by update-kernels / ltsp-update-kernels
In other words, if that file isn't there, ltsp-update-kernels will die with "I don't know how to generate a pxelinux.cfg/default for this chroot".
wafflecone, I mount all my clients under the desk anyways, with tie-wraps. I know it sounds primitive as hell, but it works surprisingly well and it is surprisingly cheap as well.
|15:29||ddave7 has left IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz, Quit: Miranda IM! Smaller, Faster, Easier. http://miranda-im.org)|
|15:42||mikkel has left IRC (firstname.lastname@example.org, Quit: Leaving)|
Cool, ty, will implement it this way unless someone objects
Hyberbyte ... I am all about zip-ties, duct-tape AND baling wire
wafflecone, so create your own frankenvesamount. :)
|16:16||SmallR2002 has left IRC (SmallR2002email@example.com, Ping timeout: 260 seconds)|
|16:17||adrianorg has joined IRC (firstname.lastname@example.org)|
|16:17||SmallR2002 has joined IRC (SmallR2002email@example.com)|
|16:23||alkisg has left IRC (alkisg!~alkisg@ubuntu/member/alkisg, Quit: Leaving.)|
|16:27||SmallR2002 has left IRC (SmallR2002firstname.lastname@example.org, Ping timeout: 245 seconds)|
|16:36||SmallR2002 has joined IRC (SmallR2002email@example.com)|
|17:35||ddave7 has joined IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz)|
|18:11||[GuS] has joined IRC ([GuS]!~gustavo@unaffiliated/gus/x-663402)|
|18:52||loather has left IRC (firstname.lastname@example.org, Ping timeout: 240 seconds)|
|19:55||alkisg has joined IRC (alkisg!~alkisg@ubuntu/member/alkisg)|
|20:28||vagrantc has joined IRC (vagrantc!~vagrant@75-150-46-245-Oregon.hfc.comcastbusiness.net)|
|20:28||vagrantc has joined IRC (vagrantc!~vagrant@freegeek/vagrantc)|
|20:37||Trixboxer has left IRC (Trixboxer!~Trixboxer@184.108.40.206, Quit: "Achievement is not the end, its the beginning of new journey !!!")|
|21:18||alkisg has left IRC (alkisg!~alkisg@ubuntu/member/alkisg, Quit: Leaving.)|
|21:27||loather has joined IRC (email@example.com)|
|21:29||komunista has left IRC (firstname.lastname@example.org, Quit: Leaving.)|
|21:54||ddave7 has left IRC (ddave7!~Miranda@ip-94-113-119-192.net.upcbroadband.cz, Read error: Connection reset by peer)|
|21:54||Steve_The_Pirate has left IRC (Steve_The_Pirate!~Gary@cpc16-haye17-2-0-cust169.haye.cable.virginmedia.com, Quit: Leaving)|
Hey guys... I added the line "X_CONF=/etc/X11/frontend-xorg.conf" to lts.conf, and then place the file 'frontend-xorg.conf' in /opt/ltsp/amd64/etc/X11... but the diskless clients don't seem to be using that file. Do I need to do something after updating lts.conf? Is there any "debug logging" I can turn on?
eddytv, have you updated the client chroot image after you put the new xorg config in /opt/ltsp/amd64/ ?
I didn't know the image had to be rebuilt after updating lts.conf... I was under the (apparently mistaken?) impression that lts.conf would allow me to specify different 'xorg.conf' files depending on the hostname of the diskless client that was booting.
I wasn't talking about lts.conf
I was talking about the xorg config file you put in the chroot
Anything you change in /opt/ltsp/ requires ltsp-update-image to work
You've specified a new xorg config in lts.conf, which is read by the client - but if you don't update the chroot image, the xorg config file won't be there.
Ah, OK. Gotcha. I misunderstood. I did run ltsp-update-image after putting 'frontend-xorg.conf' in /opt/ltsp/amd64/etc/X11
If I ssh in to the frontend, I can see the file in /etc/X11, but X doesn't appear to be using it when it starts
(that's why I was wondering if there was any sort of debug logging that would show if it processed the corresponding section of lts.conf when it booted)
Here's a thought: do I need to set CONFIGURE_X to set X_CONF?
Well, I have no idea about this issue specifically... never modified an xorg config... not with ltsp, not period...
But since LTSP clients are just Linux, you could find any debug information in /var/log/ and dmesg.
Unfortunately X just keeps exiting without one
My advice... wait around for someone who has experience with this. :)
Which might be tomorrow...
I'm off to bed. :) If you figure it out on your own, let us know.
OK. Will do.
Thanks for your help in any case.
Sure, you're welcome.
eddytv: you'll want to look at the code in /opt/ltsp/amd64/usr/share/ltsp/screen-session.d/XS*
in particular, XS90-set-x-conf
dunno what version of LTSP or OS you're running
For the X process, I see the '-config /etc/X11/frontend-xorg.conf' when I do 'ps'
and when I look at the /var/log/Xorg.7.log file, I see it referencing that file...
sounds like the LTSP part of it is doing what it's supposed to
...but it seems to be using a bunch of stuff in /usr/share/X11/xorg.conf.d/* first?
"No device specified for "My Screen"
and "No monitor specified for "My Screen"
let's back up a bit ...
which are referenced in 10-nvidia-current-latitude-e6530.conf...
eddytv: why are you needed a custom xorg.conf ?
I (made the mistake) of upgrading my mythtv backend to Ubuntu 12.04 yesterday... wanted to get to a LTS level.
I have several diskless clients that are mythtv frontends that were working splendidly with ltsp previously...
But I didn't realize that ltsp-build-client "lost" the --mythbuntu option
and now all of my front-ends are dead, much to the chagrin of the family, who can't watch any TV
by "front-end" are you meaning the thin client? or something else? i'm not too familiar with mythbuntu, other than the basic idea of it
Last night, I "fought" with the new changes to 'nbd' (old release ran it from inetd; in 12.04 it wants to run as a service with "named ports") and 'alkisg' here in #ltsp helped me get the diskless clients to at least start booting last night.
They are "thick" clients, so I ran ltsp-build-clients --fat-client-desktop mythbuntu-desktop --mount-package-cache --keep-packages --copy-sourceless
With the old --mythbuntu option, it must've pre-set the ltsp environment to automatically login to an XFCE-based "desktop" (not really needed) and then auto launch the 'mythtv-frontend' binary.
So it was a simple matter of just powering on the diskless clients, and 30 seconds later, MythTV was running and usable by non-techies :)
So... getting back to original question: the diskless clients are connected to various TVs by various means (some VGA, some HDMI, etc.) and they each have a custom xorg.conf that sets the proper modeline for the TV to display at their "native resolution"
In prior release, this was accomplished by an NFS-based copy-on-write overlay of the root (/) filesystem...
So while the client was up, you'd just edit xorg.conf "normally", and when you saved it, it got written to a client-specific overlay via NFS
Once I got each client configured properly, everything was "good"... but now things are "much different" and I'm trying to get it working in the Ubuntu 12.04 world without a specialized '--mythbuntu' option for ltsp-build-client to do everything for me
So I guess I need to figure out why the /usr/share/X11/xorg.conf.d/* stuff seems to be messing up the use of my custom xorg.conf
|23:35||risca has joined IRC (email@example.com)|
So I added a "ServerLayout" section to my xorg.conf, and now it is referencing "my" screen config instead of the one in 10-nvidia-current-* in the conf.d directory...
But now .xsession-errors just fills constantly with "X session started" and then "open: Permission denied" over and over again...
This isn't good... on my diskless client, the permissions on /tmp are "drwxr-xr-x" instead of "drwxrwxrwt". Any idea how to fix that?
As soon as I reset the defaults of /tmp on a diskless client, X started up
But that's only a temporary fix, as on each boot /tmp reverts to a standard "755" permission
|23:54||Phantomas has left IRC (Phantomas!~Phantomas@unaffiliated/phantomas, Read error: Operation timed out)|
eddytv: that's bizarre.
wonder if the mythbuntu packages added did something strange ...
Such a subtle problem; no idea how to track that down. Obviously the permissions for /tmp in /opt/ltsp/amd64 are correct
i'll see if i can reproduce on recent versions of debian ... but i suspect not.