Valerio Pachera on the Edubuntu list has been troubleshooting what seems
like the very same problem. His thread came apart somehow but you can
see all the posts here:
https://lists.ubuntu.com/archives/edubuntu-users/2012-December/thread.html
He got his clients working *most* of the time by disabling NBD
compression. (Undoubtedly performance has taken a hit.) He refers to
documentation of a previous problem with NBD compression on fat
clientswhich presumably was solved, but now gives the appearance of
having returned. See
https://help.ubuntu.com/community/UbuntuLTSP/FatClients#Reenabling_NBD_compression
On my server, there was no /etc/ltsp/ltsp-update-image.conf file, but I
created one, added the NO_COMP line, and updated theimage. This did not
solve the problem with any clients I tested. Though our respective
setups are differenton a number of points, detailed pretty well here:
https://lists.ubuntu.com/archives/edubuntu-users/2012-December/007206.html
------------------------
In my own troubleshooting, currently I'm trying to get ssh access to the
clients. I set ssh as un-removed in lts.conf, set
"PasswordAuthentication yes" in /etc/ssh/sshd_config, then updated the
image. I can tell from the forwarded syslog that sshd is listening on
port 22 -- at least on the one client that boots. But even for that
working client, "ssh <client IP>" or "ssh <user>@<client IP>" fails from
a server xterm with "Read from socket failed: connection reset by peer"
and in the forwarded client syslog I see:
Dec 4 15:23:53 ltsp135 sshd[3179]: error: Could not load host key:
/etc/ssh/ssh_host_rsa_key
Dec 4 15:23:53 ltsp135 sshd[3179]: error: Could not load host key:
/etc/ssh/ssh_host_dsa_key
Dec 4 15:23:53 ltsp135 sshd[3179]: error: Could not load host key:
/etc/ssh/ssh_host_ecdsa_key
Dec 4 15:23:53 ltsp135 sshd[3179]: fatal: No supported key exchange
algorithms [preauth]
I think this is supposed to be a trivial task. Does anyone know why I
can't get in via password authentication? Does sshd do some sort of
keys checkup even if I'm just trying to log in with a password? I don't
have to unlock root for this sort of access, do I? (This is just for
troubleshooting, so I don't see the need to unlock root or set up keys.
Though I did try unlocking root with the same result.)
And it may bear saying here that I am using LTSP-PNP with no chroot,
though I don't see how that matters here.
On 12/1/2012 9:02 PM, John Hupp wrote:
I finally got it set up so that client syslog messages forward to the
server. I thought that this would somehow point me rather directly to
the problem with some sort of a failure message. But that is not the
case. The log simply ends .....
I hope someone else will be able to read something important from it
or from the server syslog comparison between good and bad client boots
(below in the previous message).
Client syslog attached.
On 12/1/2012 5:11 PM, John Hupp wrote:
I have not been able to figure out how to send client syslog messages
to the server, but I just compared the server syslog file from a case
where the client got to a logon screen against a case where the
client went from the splash screen to a blank, black screen.
The logs are essentially the same to the point where I inserted a
dash line, and the good-boot log continues with an ldminfod entry.
(See below)
The man page of ldminfod says:
DESCRIPTION
ldminfod will output the login sessions and locales
available. it is
usually run from an inetd(8) instance. it is used by ldm(1) to
remotely
determine available login and locale settings.
EXAMPLE
add the following lines to /etc/inetd.conf(5):
9571 stream tcp nowait nobody /usr/sbin/tcpd
/usr/sbin/ldminfod
(I think /usr/sbin/ldiminfod is on the same line as 9571.)
On the LTSP server, /etc/inetd.conf only has one line that is not
commented out:
9571 stream top nowait nobody /usr/sbin/ldminfod
Does this add anything to help someone see what's going on?
-----------------------------------
Excerpt from good boot syslog:
Dec 1 16:34:10 Lubuntu1 dnsmasq-dhcp[880]: PXE(eth1)
00:50:da:64:39:4e proxy
Dec 1 16:34:13 Lubuntu1 dnsmasq-dhcp[880]: PXE(eth1) 192.168.1.135
00:50:da:64:39:4e /ltsp/i386/pxelinux.0
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: error 0 TFTP Aborted
received from 192.168.1.135
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: failed sending
/var/lib/tftpboot/ltsp/i386/pxelinux.0 to 192.168.1.135
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: sent
/var/lib/tftpboot/ltsp/i386/pxelinux.0 to 192.168.1.135
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: file
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/44454c4c-43b4-1033-8050-b6c04f313031
not found
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: file
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/01-00-50-da-64-39-4e not found
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: file
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/C0A80187 not found
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: file
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/C0A8018 not found
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: file
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/C0A801 not found
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: file
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/C0A80 not found
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: file
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/C0A8 not found
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: file
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/C0A not found
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: file
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/C0 not found
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: file
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/C not found
Dec 1 16:34:14 Lubuntu1 dnsmasq-tftp[880]: sent
/var/lib/tftpboot/ltsp/i386/pxelinux.cfg/default to 192.168.1.135
Dec 1 16:34:15 Lubuntu1 dnsmasq-tftp[880]: sent
/var/lib/tftpboot/ltsp/i386/vmlinuz-3.5.0-19-generic to 192.168.1.135
Dec 1 16:34:21 Lubuntu1 dnsmasq-tftp[880]: sent
/var/lib/tftpboot/ltsp/i386/initrd.img-3.5.0-19-generic to 192.168.1.135
Dec 1 16:34:29 Lubuntu1 nbd_server[1613]: connect from
192.168.1.135, assigned file is /opt/ltsp/images/i386.img
Dec 1 16:34:29 Lubuntu1 nbd_server[1613]: Can't open authorization
file /etc/ltsp/nbd-server.allow (No such file or directory).
Dec 1 16:34:29 Lubuntu1 nbd_server[1613]: Authorized client
Dec 1 16:34:29 Lubuntu1 nbd_server[1970]: Starting to serve
Dec 1 16:34:29 Lubuntu1 nbd_server[1970]: Size of exported
file/device is 893980672
Dec 1 16:34:35 Lubuntu1 dnsmasq-tftp[880]: sent
/var/lib/tftpboot/ltsp/i386/lts.conf to 192.168.1.135
Dec 1 16:34:38 Lubuntu1 nbd_server[1613]: connect from
192.168.1.135, assigned file is /tmp/nbd-swap/192.168.1.135
Dec 1 16:34:38 Lubuntu1 nbd_server[1613]: Can't open authorization
file /etc/ltsp/nbd-server.allow (No such file or directory).
Dec 1 16:34:38 Lubuntu1 nbd_server[1613]: Authorized client
Dec 1 16:34:38 Lubuntu1 nbd_server[1973]: Starting to serve
Dec 1 16:34:38 Lubuntu1 nbd_server[1973]: Size of exported
file/device is 536870912
-----------------------------------------------------------------
*Dec 1 16:34:53 Lubuntu1 ldminfod[1982]: connect from 192.168.1.135
(192.168.1.135)**
**Dec 1 16:34:59 Lubuntu1 nbd_server[1613]: connect from
192.168.1.135, assigned file is /opt/ltsp/images/i386.img**
**Dec 1 16:34:59 Lubuntu1 nbd_server[1613]: Can't open authorization
file /etc/ltsp/nbd-server.allow (No such file or directory).**
**Dec 1 16:34:59 Lubuntu1 nbd_server[1613]: Authorized client**
**Dec 1 16:34:59 Lubuntu1 nbd_server[1993]: Starting to serve**
**Dec 1 16:34:59 Lubuntu1 nbd_server[1993]: Size of exported
file/device is 893980672**
**Dec 1 16:34:59 Lubuntu1 nbd_server[1993]: Disconnect request
received.**
**Dec 1 16:34:59 Lubuntu1 nbd_server[1613]: Child exited with 0*
On 11/29/2012 5:53 PM, John Hupp wrote:
I thought I might be working through my last few big problems, but
instead I found another one.
After installing Lubuntu Quantal on a newly formatted disk and
setting up LTSP some weeks ago, I have been working only with a
certain two-machine test setup. In contrast to past
troubleshooting, I have not been swapping in multiple server or
client machines.
But to address something I was working on, I tried a different
client, and this one failed to boot altogether. Then I tried a
couple more different clients (different makes/models), and they had
the same behavior. That behavior is that after the client displays
the blue splash screen, which then drops to black-and-white (normal
behavior, I think), it then goes to a blank (black) screen. It does
not display the GUI login screen.
If in lts.conf I set SCREEN_07=shell, then I can successfully log in
to a shell. I also see there among the on-screen boot messages
"Starting load fallback graphics devices [fail]."
The last entry in dmesg also refers to the above failure.
The only client that works displays a (boot) message on/through the
splash screen: "lpc_ich 0000:00:1f.0: I/O space for GPIO uninitialized."
Anyone recognize this problem?
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