On 11/30/2013 1:39 PM, John Hupp wrote:
On 11/25/2013 7:30 PM, John Hupp wrote:
On 11/21/2013 11:26 AM, John Hupp wrote:
On 11/20/2013 12:37 PM, John Hupp wrote:
On 11/20/2013 12:24 PM, John Hupp wrote:
On 11/11/2013 10:31 AM, Jay Goldberg wrote:
On Fri, Nov 8, 2013 at 3:48 PM, John Hupp <l...@prpcompany.com <mailto:l...@prpcompany.com>> wrote:

    On 11/8/2013 1:42 PM, Jay Goldberg wrote:
    On Fri, Nov 8, 2013 at 11:51 AM, John Hupp
    <l...@prpcompany.com <mailto:l...@prpcompany.com>> wrote:

        On 11/7/2013 4:23 PM, David Burgess wrote:
        On Thu, Nov 7, 2013 at 1:18 PM, John Hupp
        <l...@prpcompany.com <mailto:l...@prpcompany.com>> wrote:

            On 11/6/2013 5:53 PM, John Hupp wrote:
            > I finished a new installation of LTSP-PNP on
            Lubuntu 13.10, but I find
            > that clients won't boot.
            >
            > After the Plymouth splash screen, a text screen
            reads:
            >
            > Error: socket failed: connection refused.
            > Exiting.



        Forgive me for not combing through all of the machine
        output, but at a glance your symptoms look like
        something I have encountered where the nbd server does
        not start automatically on the server. The quick fix
        was to start the service, and then I don't recall if it
        started automatically after a reboot or if I had to
        turn that on in a config file somewhere. Try 'netstat
        -lt' to see what ports you're listening on.

        db

        Thanks for a good lead (though it leads to more
        questions rather than an immediate solution).

        I find that nbd-server is running, but comparing the
        output of 'netstat -lt' on a Lubuntu 13.04 LTSP server
        that works fine, and the misbehaving 13.10 server, I
        find that on
        13.04 nbd-server listens on *: 60603, but on 13.10 it
        listens on *:nbd.

        Otherwise the output is the same for tcp on both servers
        (I don't list the tcp6 results):
        tcp        0      0 *:9571 *:* LISTEN
        tcp        0      0 localhost:55213 *:* LISTEN
        tcp        0      0 Lubuntu:domain *:* LISTEN
        tcp        0      0 192.168.1.117:domain *:* LISTEN
        tcp        0      0 localhost:domain *:* LISTEN
        tcp        0      0 *:ssh *:* LISTEN
        tcp        0      0 localhost:ipp *:* LISTEN

        The nbd-server configuration file
        (/etc/nbd-server/conf.d/ltsp_i386.conf) has the same
        contents on both installations.

        The script that launches nbd-server appears to be
        /etc/init.d/nbd-server, and it does not specify ip
        addresses or ports to listen to.  At least for the ip
        addresses,
        http://manpages.ubuntu.com/manpages/saucy/man1/nbd-server.1.html
        states that when the ip address parameter is not
        specified, nbd-server will listen on all local addresses
        on both IPv4 and IPv6.

        I don't know how to interpret the difference in how
        nbd-server is listening.


    Forgive me if I seem out of the loop, I have not used LTSP
    in over a year

    However, it does look like a port issue. Looking at my
    Debian system, /etc/services reports that NBD is on port 10809

        nbd 10809/tcp            # Linux Network Block Device


    And in the man page for nbd-server for the -port option:

The port on which to listen for new-style nbd-client connections. If not specified, the
        IANA-assigned port of 10809 is used.


    The netstat output will replace port numbers with friendly
    names if it can match up ports with entries in /etc/services

    I recall that LTSP does use its own NBD server on a
    non-standard port with a config file in a non-standard
    location as well, so it would seem that your 13.10 system
    should not show listening on *:nbd.

    Check that the nbd-server is running on the port that the
    client expects. "Connection refused" would support that the
    port the client is connecting to is "closed".

    For fun, also post the output of # iptables -L to make sure
    there are no firewall rules filtering things.

    Cheers,
-- Jay Goldberg | AvianBLUE Network Systems


    I don't know how to check that the nbd-server is running on
    the port that the client expects.  Can you tell me?

    But perhaps related to this, even though the topic was NBD
    Swap, Alkis Georgopoulos wrote in
    http://osdir.com/ml/LTSP-cluster-thin-clients/2012-08/msg00047.html
    that for Ubuntu 12.04, the NBD_PORT section [for NBD Swap] is
    obsolete since NBD is now using the IANA assigned port 10809
    and name-based exports instead of port-based.

    ------------------------------

    Iptables -L shows the default, no-rules setup:

    Chain INPUT (policy ACCEPT)
    target     prot opt source destination

    Chain FORWARD (policy ACCEPT)
    target     prot opt source destination

    Chain OUTPUT (policy ACCEPT)
    target     prot opt source destination


Unfortunately I have not run LTSP in awhile, yet alone the new "simple" LTSP. As I recall, the config files for the standalone NDB server for LTSP is stored in /etc/ltsp/ and when you change config files you must update the ltsp image because the NDB server connection happens very early in the boot process and needs to be hard coded in the client's initramfs.

I can get a test environment running tomorrow if you still would like assistance.

--
Jay Goldberg

Other work has been demanding attention, but I'm returning to this today a little.

In /etc/ltsp I only find dhcpd.conf, update-kernels.conf and ltsp-update-image.excludes -- with none of those containing anything that seems to bear on nbd-server configuration.

There are also these:
    /etc/nbd-server/config
    /etc/nbd-server/conf.d/ltsp_i386.conf
    /etc/nbd-server/conf.d/swap.conf
But again, I don't see anything there that would seem to affect where nbd-server is listening.

So yes, if you're still game for it, I'm happy for all the further help I can get.

A little later I'm thinking that I will install Lubuntu 13.10 (with no updates and no other programs installed) + LTSP_PNP in VMWare Player and test that. Of course if that worked it should give me some clues. But if someone else in possession of Ubuntu 13.10 were to run a similar test, that could help to narrow the field of inquiry to something in LXDE. I know that there have been changes to LXSession manager and related parts in 13.10, but as far as I know these would not bear on nbd-server (which I have seen above is running -- at least one instance of it).

That Lubuntu vs Ubuntu 13.10 is blunt-object troubleshooting however, and I'm open to finer ideas if someone can tell me how.

For instance, since the client machine has an initramfs that seems to be working at the point of failure (there is a working prompt), can I run something useful from there?


I installed Lubuntu 13.10 (with no updates and no other programs) + LTSP-PNP in a VMWare Player virtual machine, but when tested with a client, its PXE booter fails with the error: "No boot filename received."

So in this setup I so far find out nothing useful. At least in the real metal install I have a clean PXE boot.

If someone can help me get past this obstacle I may be able to find out a something.

-------------------------------

I also copied and pasted the output of the LTSP install commands into a file which you can download at http://www.prpcompany.com/ltsp/vm_ltsp_install_log.zip (I tried just pasting it in here but it made the post run afoul of a size limit.)

Perhaps of immediate interest from that log is the output of the installation of ltsp-server-standalone. It includes this:

########################################
Setting up nbd-server (1:3.3-3ubuntu1) ...

Creating config file /etc/nbd-server/config with new version
Adding system user `nbd' (UID 110) ...
Adding new group `nbd' (GID 119) ...
Adding new user `nbd' (UID 110) with group `nbd' ...
Not creating home directory `/etc/nbd-server'.

** (process:3234): WARNING **: Could not parse config file: The config file does not specify any exports
** Message: No configured exports; quitting.
 nbd-server.
########################################

Is that normal?

I did not figure out why the LTSP setup in VMWare Player fails.

But I did reinstall 13.04 on real hardware in order to copy the output of the LTSP installation commands and compare them to the results under 13.10. I did not discover anything very illuminating, but I did find the same nbd-server setup messages in both, so in light of the fact that LTSP works under 13.04, the above WARNING is insignificant.

I have duplicated the LTSP setup on a fresh install of Ubuntu 13.10, and I find the very same failure.

So the problem does not appear to be connected to the desktop environment or to changes in the desktop environment between 13.04 (where LTSP worked) and 13.10.


I found out that the Busybox shell supports 'dmesg' and entered that at the working initramfs prompt.

I think the last few lines of the output support the premise that this is an nbd problem:

block nbd0: Attempted send on closed socket
end_request: I/O error, dev nbd0, sector 2
EXT3-fs (nbd0): error: unable to read superblock
block nbd0: Attempted send on closed socket
end_request: I/O error, dev nbd0, sector 2
EXT4-fs (nbd0): error: unable to read superblock
block nbd0: Attempted send on closed socket
end_request: I/O error, dev nbd0, sector 2
FAT-fs (nbd0): unable to read boot sector

As I reported in another thread here, I now have copies of the presumably-relevant initramfs startup scripts (/init, /scripts/local-top/nbd, /scripts/local-top/nbd-ltsp and /sbin/nbd-client-proxy), but I don't know how to read them to determine what nbd-client command is being used, or how I might run an nbd-client command in the Busybox shell for testing.

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