Fresh install: LTSP on Ubuntu 13.10: "Error: socket failed: connection refused"

Rippl, Steve rippls at woodlandschools.org
Mon Dec 9 18:40:17 UTC 2013


Not speaking to your problem specifically, but our experience over the past
few years has been that nbd has been problematic in many ways. Through
multiple versions of nbd and kernel we've been able to consistently crash a
thread at one client and hence block the entire server which then needed a
restart, booting off all current clients.  With multiple labs on clustered
servers turning on and off throughout the day it would happen regularly and
became untenable.

We've since gone back to using nfs shares for the images, they may be a
little slower (although we've not noticed it cause any real visible
slow-down and we're on fat-clients) but are infinity more stable! All the
options to utilize nfs are still in Ubuntu LTSP, just not advertised as far
as we can tell.

Again, I realize this doesn't help you, it's just your message prompted me
to get this out on the list in case others find it useful.




On Sat, Dec 7, 2013 at 5:23 PM, John Hupp <edubuntu at prpcompany.com> wrote:

>  On 11/30/2013 1:24 PM, John Hupp wrote:
>
> On a fresh installation of Ubuntu 13.10 and LTSP, the LTSP client fails to
> boot.  After a good PXE boot, successful TFTP, and the splash screen, boot
> stops with the message "Error: socket failed: connection refused."
>
> Then I'm dumped to the console at a working initramfs prompt.
>
> I follow with the console messages, starting with the last message that
> one sees in a good boot, followed by all the bad messages:
>
> Trying to load: pxelinux.cfg/default        ok
> mount: mounting /dev/nbd0 on /root failed: Invalid argument
> /scripts/init-bottom/ltsp: line 27: panic: not found
> chroot: can’t execute ‘/usr/bin/test’: No such file or directory
> mount: mounting /root on /rofs failed: Invalid argument
> mount: mounting /rofs on /root/rofs failed: Invalid argument
> mount: mounting /dev /root/dev failed: No such file or directory
> mount: mounting /sys on /root/sys failed: No such file or directory
> mount: mounting /proc on /root/proc failed: No such file or directory
> Target filesystem doesn’t have requested /sbin/init-ltsp.
> No init found.  Try passing init= bootarg.
>
> BusyBox v1.20.2 (Ubuntu 1:1.20.0-8.1ubuntu1) built-in shell (ash)
> Enter ‘help’ for a list of built-in commands.
>
> (initramfs) _
>
> -----------------------------------------------
>
> This is on a fresh default installation of Ubuntu 13.10.  I followed with
> this standard LTSP-PNP setup (using a single NIC):
>
> sudo -i
> add-apt-repository --yes ppa:ts.sch.gr
> apt-get update
> apt-get --yes install dnsmasq ltsp-server-standalone ltsp-client
> ldm-lubuntu-theme
> ltsp-config dnsmasq
> echo 'IPAPPEND=3' >> /etc/ltsp/update-kernels.conf
> /usr/share/ltsp/update-kernels
> ltsp-update-image --cleanup /
> ltsp-config lts.conf
>
> -----------------------------------------------
>
> I modify the installation in just two ways:
>
> 1) To fix LTSP Client Boot Error: "PXE-E32: TFTP open timeout," in
> /etc/dnsmasq.d/network-manager replace the "bind-interfaces" line with a
> "bind-dynamic" line.
>
> 2) To fix Internet DNS Name Resolution broken by LTSP setup, edit
> /etc/dnsmasq.d/ltsp-server-dnsmasq.conf and comment out the port=0 line.
>
> ===============================================
>
> I also found that the very same thing happens with *Lubuntu* 13.10, so the
> issue does not appear to be connected to any changes in the desktop
> environment between 13.04 (where LTSP worked) and 13.10.
>
> One person suggested that the kernel used in 13.10 might not support my
> network card, but when booting to the Live CD, the network card works fine.
>
> Another person or two suggested that the problem was some issue between
> the NBD server and client, but so far I have no specific troubleshooting
> measures.  On the server, 'sudo ps -a | grep nbd' shows that there is one
> instance of nbd-server running. 'Netstat -lt' shows that for tcp (the tcp6
> results are irrelevant here, right?), listening is occurring at
>     *:9571
>     Dell-Ubuntu:domain
>     Dell-Ubuntu.loca:domain
>     localhost:domain
>     *:ssh
>     localhost:ipp
>
> Has anyone else experienced this or found out what is wrong?
>
>
>
> I think I have good evidence now that this is a bug in kernel-level nbd
> support.
>
> Saucy uses kernel 3.11.0-12.19 in its initial default configuration, and
> the error occurs under this kernel.
>
> But I installed 3.9.0-4.9 (which was also published for Saucy), and the
> client boots normally when it uses that kernel.
>
> Testing has been hampered by the fact that some of the pre-3.11.0-12.19
> kernels break networking (e.g. 3.11.0-0.3 and 3.10.0-2.10), and I don't
> know if/how to test for working kernel nbd support except by booting an
> LTSP client.  Nonetheless I'll try to narrow down where the failure occurs.
>
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>


-- 
Steve Rippl
Technology Director
Woodland Public Schools
360 841 2730
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