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====== Edubuntu : LTSP, résolution de problèmes ======

Page en cours de construction : en attendant, vous pouvez consulter les "FAQ" [[https://help.ubuntu.com/community/EdubuntuFAQ#head-89dcf777d5d9c472dd5aa9a15bb17de90c6f0860|ici]] (en anglais) :

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Frequently asked questions about Edubuntu. This page contains aggregated information taken from our mailing lists, IRC channel and other modes of support (refer to https://wiki.edubuntu.org/Edubuntu/Community/Communication)

===== General =====

==== Where can I get help with Edubuntu? ====
We have a number of communication channels available, refer to https://wiki.edubuntu.org/Edubuntu/Community/Communication. Specifically:
 * ''The #edubuntu IRC channel on the Freenode IRC network''
 * ''The Edubuntu Users Mailing list: https://lists.ubuntu.com/mailman/listinfo/edubuntu-users''

===== Thin Clients & LTSP =====

==== I can login directly to the server, but I cannot log in to my thin clients. ====
Try logging into the server and running:
   {{{sudo ltsp-update-sshkeys}}}

When your thin client logs you into the server, it checks the server's identity by looking at its ssh key.  Most often, if the server's IP address gets changed, the key no longer matches and logins fail.  The above will update the list of keys and IP addresses.

More information on debugging logins is on the [https://wiki.ubuntu.com/DebugThinClientLogin DebugThinClientLogin] page.

==== Where can I get good documentation on Edubuntu thin clients? ====
 * ''The Edubuntu Handbook -- http://doc.ubuntu.com/edubuntu/handbook/C/''
 * ''The Ubuntu LTSP Wiki https://help.ubuntu.com/community/UbuntuLTSP''
 * ''The LTSP Manual --  http://wiki.ltsp.org/twiki/bin/view/Ltsp/Documentation''
 * ''The Gentoo LTSP Guide -- http://www.gentoo.org/doc/en/ltsp.xml''

==== What sort of hardware can I use for the thin clients and the server? ====
This is discussed in detail on this page: https://help.ubuntu.com/community/EdubuntuDocumentation/EdubuntuCookbook/HardwareRequirements

==== Are there graphical management tools for the thin clients? ====
Yes.  Under the {{{System->Administration}}} menu, choose {{{Thin Client Manager}}}

==== Can I have some of my thin clients work as anonymous web kiosks? ====
Yes.  You need to build a separate LTSP root environment on the server, eg.

{{{sudo ltsp-build-client --kiosk --base /opt/ltsp-kiosk/}}}

and then, configure the DHCP server ({{{/etc/ltsp/dhcpd.conf}}}) to tell those thin clients to use the kiosk root

{{{option root-path="/opt/ltsp-kiosk/"}}}

==== How do I modify the login screen on my thin clients? ====
The login screen on thin clients is generated by ldm running on the thin client.  You can modify this, in the ltsp chroot environment {{{/opt/ltsp/i386/usr/share/ldm/themes/}}} by taking a copy of the theme, making your copy the default and modifying the artwork
{{{sudo cp -r /opt/ltsp/i386/usr/share/ldm/themes/Edubuntu /opt/ltsp/i386/usr/share/ldm/themes/MyTheme
sudo rm /opt/ltsp/i386/usr/share/ldm/themes/default
sudo ln -s /opt/ltsp/i386/usr/share/ldm/themes/MyTheme /opt/ltsp/i386/usr/share/ldm/themes/default}}}

Now just modify the images in {{{/opt/ltsp/i386/usr/share/ldm/themes/MyTheme}}}

==== Sound doesn't work on flash applets (eg youtube videos) on my thin clients! ====
This was a known issue for a long time with the closed source adobe flash plugin.  It has recently been fixed, although the fix did not make it into Edubuntu feisty.  The simplest fix is to download and install the libflashsupport package on your server with these commands:
{{{wget http://pulseaudio.vdbonline.net/libflashsupport/libflashsupport_1.0~2219-1_i386.deb
sudo dpkg -i libflashsupport_1.0~2219-1_i386.deb}}}
For more info on the fix and the work done, you can look here:
  * http://pulseaudio.revolutionlinux.com/PulseAudio

==== Can I set up LTSP over a wireless connection? ====
A short overview about how thin clients boot:
 1. thin client starts and sends a PXE or Etherboot request to the network
 1. DHCP server answers and tells the client where to get the kernel and the system from
 1. client pulls kernel via TFTP and mounts the filesystem via NFS from the server

WLAN cards don't support PXE or Etherboot, so there is no way for the thin client to send a PCE or Etherboot request to the network with a wireless card. The only way to achieve this would be to have the ''kernel'' and ''initramfs'' stored locally somehow (which indeed is not a LTSP setup anymore but rather a minimal local boot that mounts its filesystem via NFS). Additionally you would need to handle the ESSID for the WLAN as well as potential encryption via ''bootoptions''.

It is not impossible to build a locally booting WLAN image, but you will always need local media (usb-stick, flashcard or CD) to boot from and it
is far from being supported by us (implementing it will take some time and testing).

==== My Edubuntu server keeps filling up with files on /tmp!!! ====

This was a problem up to and including Edubuntu Feisty.  They are old, temporary "swap" files from thin clients which were not shutdown properly. Adding the following line to /etc/hosts.allow:

nbdswapd: ALL: keepalive

should stop newly created files getting left around.  You may find it easiest to reboot to clear the existing ones though.

==== How do I set the root password on the thin clients? ====

In order to debug individual thin clients it can be useful to be able to login in a text session on the thin client.  To do this:
 1. Login as normal and start a terminal (under applications->accessories menu).
 1. Type {{{sudo chroot /opt/ltsp/i386}}} and press return.  You will be prompted for your password.
 1. At the next prompt, type {{{passwd}}} and press return.  You will be prompted for the root password for the thin clients.
 1. If you're running gutsy (v7.10) or newer, you must now run {{{sudo ltsp-update-image}}} and reboot the thin client you wish to login to.

Having done the above, you can go to any of your thin clients, hold <ctrl><alt> and press F1.  You should now be able to login with the username root and the password you set.

==== How can I automatically create large numbers of users? ====

There isn't currently a way within the standard system "users and groups" manager tool.  However, several ways exist which were mentioned in this thread on edubuntu-users mailing list.

https://lists.ubuntu.com/archives/edubuntu-users/2007-January/thread.html#529

most of the ideas centre around the {{{createusers}}} script which is part of Matt Oquist's smbldap setup script.

http://www.majen.net/smbldap/

==== I can't get USB storage keys/devices to work on thin clients ====

One of the most common reasons for USB storage devices not to work is the user needs to be in the {{{fuse}}} group.  By running the {{{groups}}} command a user can check what groups he is in.  You can change user groups in the user admin tool which you use to create users.

If that isn't the answer, there are instructions for debugging local devices here:

* https://wiki.ubuntu.com/DebugLocalDev

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