Das Werkstatt

Posted: **Mon Jul 05, 2010 9:33 pm**

I'm trying to upgrade from LTSP 4.2 to 5.1.10 on Debian Lenny.
Here's a list of problems/errors I got so far:

In dhcpd.conf, I've accidentially used the pxelinux.0 image from 4.2, but pointed "filename" to 5.1.10's root (/opt/ltsp-5.1.10/i386) got me the following errormessage on the client:

/etc/rc.config.sysinit: No such file or directory
boot failed for selinuxfs on /selinux: No such file or directory

The client finds the pxelinux.0, but outputs the following errormessage about ~50 times:

rpc failed: 2

(...and the drops to a busybox shell)

Trying to mount the NFS share in the busybox shell:

mount: mounting xxx on yyy failed: Invalid argument"

Posted: **Wed Sep 08, 2010 9:33 pm**

[PROBLEM]
When trying to boot the same kernel as used on the LTSP-5 host, it can't find its modules.dep:

FATAL: Could not load /lib/modules/2.6.29.4/modules.dep: No such file or directory"

It seems to be a current bug with "mkinitramfs" versions prior to 0.94 (see debian bugs for details).

[SOLUTION]
If you *do* have your kernel compiled with modules, an empty modules.deb won't do the trick.
You can generate a valid modules.dep (and other module dependency information) for your initramfs image like this:

Code: Select all

depmod -a -b /tftpboot/ltsp/i386/initramfs/

Posted: **Wed Sep 08, 2010 9:43 pm**

Useful resources for debugging this stuff:
- HowTo view and modify and recreate initrd.img
- Debian diskless cluster HowTo

Posted: **Wed Sep 08, 2010 11:18 pm**

So, after reading the scripts that LTSP 5 is using to generate its initrd.img file, I've figured out that it copies most of its binaries from /usr/lib/klibc.

That's a nice collection of vitally necessary applications, but the "rpc failed: 2" problem can locally be reproduced on the LTSP 5 host, by trying to use the klibc's nfsmount. For example:

Code: Select all

/usr/lib/klibc/bin/nfsmount $NFS_SOURCE $NFS_TARGET

Spits out the same error. great. Nice to reproduce and check *if* the LTSP client would even remotely be able to mount NFS with the binaries it has in its initrd image.

things I've tried:
1) don't use bin/nfsmount, but bin/mount with "-t nfs" argument:
Won't work, because klibc's mount is too slim to support non-native filesystems. *sigh*

2) Use the host's /bin/mount instead of klibc's:
Also fails, because for "mount -t nfs" calls external binaries in "/sbin/" for the filesystem you're trying to mount.
e.g.:
"/bin/mount -t nfs" calls "/sbin/mount.nfs" and forwards some arguments.

3) So I've copied "/sbin/mount.nfs*" from the host to the /sbin/ folder of the initrd image:
Now that worked, but in the end I've used "/sbin/mount.nfs" directly to avoid further troubles with "/bin/mount" on the client.

Posted: **Mon Nov 29, 2010 8:44 pm**

[PROBLEM]

Re: LTSP 5.1.10 & Debian Lenny: problems. Please change to another screen

[SOLUTION]
LTSP 5 seems to "lock" the first terminal (=SCREEN_01), so you can simply edit the ltsp.conf file and move SCREEN_01 to SCREEN_07.

Open '/opt/ltsp/i386/etc/lts.conf' and search for a block like this:

Code: Select all

[term00]
XSERVER            = ati
SCREEN_01          = startx
SCREEN_02          = shell
#        X_MODE_0           = 1024x768
#        X_MODE_1           = 800x600
#        X_MODE_2           = 640x480

Code: Select all

[term00]
XSERVER            = ati
SCREEN_02          = shell
SCREEN_07          = startx
#        X_MODE_0           = 1024x768
#        X_MODE_1           = 800x600
#        X_MODE_2           = 640x480

Posted: **Mon Dec 06, 2010 9:47 pm**

[PROBLEM]
After booting an LTSP 5 client, I get the X login screen - but when I try to logon with invalid credentials, it says:

Verifying password please wait.

After approximately 2 minutes, the X session on the client closes itself, drops to a terminal screen (without login).

I'm running LTSP 5 on Debian Lenny, but according to an entry on the ltsp-discuss mailing list, this problem seems to exist since Etch-Backports (2008).

[SOLUTION]
I currently don't have a solution, but thanks to the ltsp-discuss mailing list, I've found a workaround.
It seems that the SSH connection to the LTSP-server gets stuck. "ps ax" shows the dead ssh session:

/usr/bin/ssh/ -Y -t -M -S /var/run/ldm_socket_vt7_192.168.0.x guest@192.168.0.x echo LTSPROCKS ; ...

Killing the SSH session restores the graphical login.

Log on at another terminal (e.g. Ctrl+Alt+F1)
ps ax | grep ldm_socket
kill -9 [process-id-of-ssh-session]

...it's a workaround.

Posted: **Mon Dec 06, 2010 9:54 pm**

[PROBLEM]
Some users that work perfectly fine as client logins on LTSP 4, can't login to LTSP 5.

In the LTSP server's /var/log/auth.log, you can see why they're blocked:

Dec 6 20:21:59 ltsp_server sshd[10328]: User guest from lstp_client not allowed because not listed in AllowUsers
Dec 6 20:21:59 ltsp_server sshd[10328]: Failed none for invalid user guest from 192.168.0.x port 54903 ssh2
Dec 6 20:21:59 ltsp_server sshd[10332]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=client_hostname user=guest
Dec 6 20:22:02 ltsp_server sshd[10328]: error: PAM: Authentication failure for illegal user guest from ltsp_client
Dec 6 20:22:02 ltsp_server sshd[10328]: Failed keyboard-interactive/pam for invalid user guest from 192.168.0.x port 54903 ssh2

[SOLUTION]
LTSP5 connects its X session to the server over SSH. Therefore, all users that shall be able to login at the LTSP clients, must be allowed to connect to the SSH daemon of the LTSP server.

Open your /etc/ssh/sshd_config and verify/check/modify for lines with any of the following keywords:

DenyUsers
AllowUsers
DenyGroups
AllowGroups

Posted: **Mon Dec 06, 2010 11:05 pm**

Pulseaudio sound Howto:
http://bootpolish.net/pageloader.pl?pag ... ltsp5sound

Posted: **Wed May 16, 2012 3:23 pm**

More links:

http://wiki.debian.org/LTSP/Howto
http://bootpolish.net/home_ltsp_ltsp5install
https://help.ubuntu.com/community/Ubunt ... TSP_Server

Installing LocalDevice support:
http://bootpolish.net/home_ltsp_ltsp5localdevices
Troubleshooting LocalDevice support

Das Werkstatt

LTSP 5.1.10 & Debian Lenny: problems...

LTSP 5.1.10 & Debian Lenny: problems...

Re: LTSP 5.1.10 & Debian Lenny: problems...

Re: LTSP 5.1.10 & Debian Lenny: problems...

klibc's nfsmount is fucked up.

SCREEN_01 contains a screen script startx...

LTSP/LDM: 2 min timeout and crash of Xsession on wrong login

Login problems

Re: LTSP 5.1.10 & Debian Lenny: problems...

Re: LTSP 5.1.10 & Debian Lenny: problems...