New version of LTSP

[dhicks]

Hello All,

Via Slashdot: version 5.2 of LTSP is out. Seemingly, new features include better "fat-client" performance, allowing you to run some applications client-side.

It sounds like LTSP is basically now a network-bootable OS that can connect to Windows Terminal Services machines, Linux X sessions, 2X servers and so on, and be capable of running a web browser client-side, too. Does anyone have any experience in getting LTSP set up as above? I have a room of Edubuntu thin clients running, but that was just me following the instructions - how do I get a client-side web browser with Flash and PDF viewers going? If I can get that bootable (at a reasonable load time) over the network then I just need to plug in a couple of TS servers, pay for TS and MS Office CALS, then chuck all our PC's harddrives away and have them all boot off the network...

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David Hicks

[CyberNerd]

Hi Dave.
We've set up a test run of this using 10.4 beta. It looks promising (test using 1Ghz via 256MB - 330 atoms 2GB) boots into (LXDE) quickly, is fast and usable.
My main prerogative is getting a browser/flash off our terminal servers and LTSP 5.2 looks just the thing.
The localapps is as simple as chrooting into the /opt/ltsp/i386 installing FF, building the client and then running 'ltsp-localapps firefox' to invoke the client. Works for the Citrix terminal services client locally as well for streaming apps (the published applications even automagically appear in the start menu)
This works fine for local users but we have run into a series of problems:
winbind use default domain = yes is broken in "likewise" for domain authentication https://bugs.launchpad.net/ubuntu/+s...en/+bug/534629
I've not worked out how to set the clientname and pass it through to the Citrix terminal server, we need this to assign printers in citrix
Local apps only seems to work for local users, we've not been able to get it running using AD/likewise authenticated user accounts.
not got homedrive mapping working yet (but not really an issue, as citrix does this as soon as a program is run)
I've been thinking about taking out the authentication and just using smoothwall/Citrix for auth - but this may raise problems with browser privacy....

[dhicks]

The localapps is as simple as chrooting into the /opt/ltsp/i386 installing FF, building the client and then running 'ltsp-localapps firefox' to invoke the client.

Ah, "simple" is always nice!

winbind use default domain = yes is broken in "likewise" for domain authentication

We've been using Ubuntu 9.10 workstations with the latest version of Likewise Open installed separatly rather than using the version you get with apt-get. I've got a bunch of notes somewhere detailing the problems I found along the way - I'll try and get a 10.4 install done as soon as possible to see how it all works now.

We'll be using Terminal Services rather than Citrix, I'll see how well that works.

We have a room currently running off a "standard" Edubuntu LTSP server - I just stuck the Ubuntu Server CD in, told it to install a thin-client setup and away it went. However, the machines we are using as thin clients should be prefectly capable of doing web browsing locally, and I'd like to get some more Linux-based machines around the school - I have a bunch of machines sat spare not doing anything at the moment, we should get them in to use. Ideally, I think this could be accomplished by using LTSP booting over PXE. One issue I've thought of is bandwidth - having one server dishing out OS boot images big enough to have a web browser and assorted thin client applications might get a bit slow with workstations scattered around our somewhat sprawling building.

Anybody any thoughts about having caching servers around the place? Should it be possible to have a number of PXE servers around, all of which get OS image updates from some central server? I can figure out how to get one server to distribute OS image changes to a bunch of other servers easily enough, but how do I organise several PXE boot servers on one network? If you have more than one PXE boot server do they argue and cause confilcts, or does a PXE client simply magically find the nearest PXE server somehow?

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David Hicks

[SYNACK]

PXE relies on DHCP which is segmented via subnets you could if you have not already, split the schools clients up into multiple sub domains. Then you would simply specify the address of the server that you wanted to service that subnet in the DHCP config for each one.

Depending on your DHCP server and setup it may even be possible to write a filter or statically define hosts so that they are split evenly all on the one subnet. Multiple PXE servers can coexist happily as they are really just TFTP servers pointed to via DHCP. If the clients are not pointed to a specific server then it will just sit quietly in the corner without causing issues.

[CyberNerd]

We already have 300 ish thinstation clients which boot PXE and then load a kernel via tftp from the same server. I don't think it is a big problem because the boot time is quick and clients tend not to boot at exactly the same time.
If you really want to spread a PXE load then it could be done by specifying a different tftp server in the DHCP config.
your /tftpboot/pxelinux.cfg/default would then look something like this:

default LTSP
  LABEL LTSP
  kernel vmlinuz
  append ro initrd=initrd.img  nbdroot=172.16.0.45:2000

to specify 172.16.0.45:2000 as the ndb server

[dhicks]

We have a room currently running off a "standard" Edubuntu LTSP server - I just stuck the Ubuntu Server CD in, told it to install a thin-client setup and away it went.

Update: this option has dissapeared in Edubuntu 10.04, and all my attempts to get LTSP working from a 10.04 server have thus far failed. I've tried installing ltsp-server-standalone with apt-get, I've tried installing the LTSP option from the alternate install CD, I've tried updating the client OS image with the LTSP update script. Nothing works - the furthest I've gotten so far is for the thin clients to pick up the DHCP server, load and unpack (I think) the boot image and then stop.

Frustratingly, I know it must be possible to get a working 10.04 LTSP server because the Edubuntu Live DVD works a treat - you just boot it up, select "run an LTSP" server and two minutes later you can boot thin clients. I've even tried copying the boot image from the Live DVD to an installed server - it still didn't work.

If anyone has any thoughts or ideas, they'd be much appreciated...

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David Hicks

[dhicks]

If anyone has any thoughts or ideas, they'd be much appreciated...

...okay, problem solved: the issues turned out to be with the version of Etherboot we were using on our client boot floppies. The BIOS on the old RM all-in-ones we're using as thin clients needs you to select "network boot", which is a bit pointless, so we're booting them from floppies with an Etherboot image on. It turns out that this image has some random issue booting Debian / Ubuntu/ Edubuntu PXE images - the PXE image loads and unpacks but then freezes, giving no useful information as why it's failing, which led me for a long time (2 whole long, tedious days...) to think there was something wrong server-side. It actually turns out there's nothing wrong with the server, we just needed to update the boot image on the floppies (we used the gPXE image available from ROM-o-matic.net for gPXE 1.0.0 - seems to work fine).

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David Hicks

[dhicks]

winbind use default domain = yes is broken in "likewise" for domain authentication https://bugs.launchpad.net/ubuntu/+s...en/+bug/534629

Solved:

[ubuntu] Use default domain with likewise-open 5.4 - Page 2 - Ubuntu Forums

Also, it seems to be best to install likewise-open via the command line, e.g.:

apt-get install likewise-open5
domainjoin-cli join CONVENT.altonconvent.org.uk administrator

Using the GUI tool just gave me a LSASS error.

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David Hicks

[dhicks]

Okay, so now our Edubuntu 64-bit LTSP server seems to be refusing to let more than 14 users log on and use workstations at a time. If I log on 14 users and load TuxPaint everything is fine, number 15 seems to log on but TuxPaint then doesn't start properly and neither does any other software on any other workstations from then on until I physically reboot the server and all the workstations.

Am I running in to some arbitary limit on something? Is something limited to 14-odd (give or take) connections somewhere in Ubuntu? I've tried mount points - each user's home directory on a remote server is mounted via gvfs-mount in a logon script, but disabling that script seems to make no difference. I don't think RAM and/or swap space is an issue - I've loaded up 14 workstations with TuxPaint, GNUPaint and Firefox running a YouTube video. YouTube ran rather slowly by the time three or four machines were trying to use it at once, but otherwise everything was fine. On loading up workstation 15, everything conked out again.

Anyone any ideas at all?

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David Hicks