[Ltsp-discuss] NBD content drop?!?

[Lars Madsen]

I'm taking the liberty to spam again.

I'm currently observing some rather odd behaviour.

My LTSP system (Ubuntu 12.04 clients) runs in Virtual Box on my office PC. Everything thing working just fine.

For the production system (also running Ubuntu 12.04), I have a virtual server acting as the boot server etc sitting in the IT department system, i.e. the network distance is a bit longer (some miles).

Our production clients are working sort of ok, some problems with LDM freezes etc.

Today I just noticed that on the images servered up by the production system some services are not running. For example cron.

Dropping into a shell on a test virtual client confirms this

ps -ef | grep cron

reveals no cron.

also no cron is listed in /etc/init.d/, even though it *is* in /opt/ltsp/i386/etc/init.d in the chroot.

I also tried unpacking the the exact image being served to the clients, there everything is peachy, /etc/init.d/cron is a soft link as usual.

WTF is going on here.

Any idea as to how exactly one is suppose to debug this?




/Lars Madsen
Institut for Matematik / Department of Mathematics
Aarhus Universitet / Aarhus University
Mere info: http://au.dk/***@imf / More information: http://au.dk/en/***@imf


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[Vagrant Cascadian]

On 2015-01-30, Lars Madsen wrote:
> Today I just noticed that on the images servered up by the production
> system some services are not running. For example cron.
...
> also no cron is listed in /etc/init.d/, even though it *is* in
> /opt/ltsp/i386/etc/init.d in the chroot.
>
> I also tried unpacking the the exact image being served to the
> clients, there everything is peachy, /etc/init.d/cron is a soft link
> as usual.

There are a number of services that are disabled at boot by default on
Debian/Ubuntu LTSP clients. You may need to add cron and other services
you want to KEEP_SYSTEM_SERVICES in lts.conf.

Look for /usr/share/ltsp/init-ltsp.d/50-rm-system-services in the client
chroot/image for the code that implements it.


The NBD disconnections you described earlier *might* be explained by
/usr/share/ldm/rc.d/I01-nbd-checkupdate, which checks for updated NBD
every time LDM is started. That wouldn't explain your LDM sessions
freezing, though.

For further debugging, you might want to enable remote syslogging by
configuring rsyslog on the server and setting SYSLOG_HOST=server in
lts.conf.


live well,
vagrant

[Lars Madsen]

>
>
> ________________________________________
> From: Vagrant Cascadian [***@debian.org]
> Sent: 30 January 2015 22:40
> To: ltsp-***@lists.sourceforge.net
> Subject: Re: [Ltsp-discuss] NBD content drop?!?
>
> On 2015-01-30, Lars Madsen wrote:
> > Today I just noticed that on the images servered up by the production
> > system some services are not running. For example cron.
> ...
> > also no cron is listed in /etc/init.d/, even though it *is* in
> > /opt/ltsp/i386/etc/init.d in the chroot.
> >
> > I also tried unpacking the the exact image being served to the
> > clients, there everything is peachy, /etc/init.d/cron is a soft link
> > as usual.
>
> There are a number of services that are disabled at boot by default on
> Debian/Ubuntu LTSP clients. You may need to add cron and other services
> you want to KEEP_SYSTEM_SERVICES in lts.conf.
>
> Look for /usr/share/ltsp/init-ltsp.d/50-rm-system-services in the client
> chroot/image for the code that implements it.
>
>
> The NBD disconnections you described earlier *might* be explained by
> /usr/share/ldm/rc.d/I01-nbd-checkupdate, which checks for updated NBD
> every time LDM is started. That wouldn't explain your LDM sessions
> freezing, though.
>
> For further debugging, you might want to enable remote syslogging by
> configuring rsyslog on the server and setting SYSLOG_HOST=server in
> lts.conf.
>
>
> live well,
> vagrant


Thanks, I discovered 50-rm-system-services litterally minutes ago
(while examing the contents of the image)

I'm guessing we are getting hit by the fact that we are using quite
low powered clients (on the other hand they are quite silent).

I'll continue to digg through this

I was going to make a workaround for the freezing stuff by having the
clients shutdown automatically if there is no ssh process and ldm has
a certain age

Interesting script to write, learned a bit extra. Then I was hit by a
missing cron on production.

Turned out my VM client for my testing system had 1024MB RAM, and my
VM for testing on production had 128MB. So I never saw the difference.

/daleif

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[Lars Madsen]

>
> There are a number of services that are disabled at boot by default on
> Debian/Ubuntu LTSP clients. You may need to add cron and other services
> you want to KEEP_SYSTEM_SERVICES in lts.conf.
>
> Look for /usr/share/ltsp/init-ltsp.d/50-rm-system-services in the client
> chroot/image for the code that implements it.
>
>
> The NBD disconnections you described earlier *might* be explained by
> /usr/share/ldm/rc.d/I01-nbd-checkupdate, which checks for updated NBD
> every time LDM is started. That wouldn't explain your LDM sessions
> freezing, though.
>
> For further debugging, you might want to enable remote syslogging by
> configuring rsyslog on the server and setting SYSLOG_HOST=server in
> lts.conf.
>
>

Using KEEP_SYSTEM_SERVICES=cron

works just fine

however SYSLOG_HOST does not even after I switched to

KEEP_SYSTEM_SERVICES="cron rsyslog"
SYSLOG_HOST=IP address

the syslog host is just the boot server.

Do I need to configure anything special to get the server to receive
remote syslog?

/daleif


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look and join the conversation now. http://goparallel.sourceforge.net/
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[Lars Madsen]

Just to answer my own question

On the server, make sure the following lines are not commented in /etc/rsyslog.conf

# provides UDP syslog reception
$ModLoad imudp
$UDPServerRun 514

# provides TCP syslog reception
$ModLoad imtcp
$InputTCPServerRun 514


then restart rsyslog


/Lars Madsen
Institut for Matematik / Department of Mathematics
Aarhus Universitet / Aarhus University
Mere info: http://au.dk/***@imf / More information: http://au.dk/en/***@imf


________________________________________
From: Lars Madsen [***@math.au.dk]
Sent: 02 February 2015 13:49
To: ltsp-***@lists.sourceforge.net
Subject: Re: [Ltsp-discuss] NBD content drop?!?

>
> There are a number of services that are disabled at boot by default on
> Debian/Ubuntu LTSP clients. You may need to add cron and other services
> you want to KEEP_SYSTEM_SERVICES in lts.conf.
>
> Look for /usr/share/ltsp/init-ltsp.d/50-rm-system-services in the client
> chroot/image for the code that implements it.
>
>
> The NBD disconnections you described earlier *might* be explained by
> /usr/share/ldm/rc.d/I01-nbd-checkupdate, which checks for updated NBD
> every time LDM is started. That wouldn't explain your LDM sessions
> freezing, though.
>
> For further debugging, you might want to enable remote syslogging by
> configuring rsyslog on the server and setting SYSLOG_HOST=server in
> lts.conf.
>
>

Using KEEP_SYSTEM_SERVICES=cron

works just fine

however SYSLOG_HOST does not even after I switched to

KEEP_SYSTEM_SERVICES="cron rsyslog"
SYSLOG_HOST=IP address

the syslog host is just the boot server.

Do I need to configure anything special to get the server to receive
remote syslog?

/daleif


------------------------------------------------------------------------------
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sponsored by Intel and developed in partnership with Slashdot Media, is your
hub for all things parallel software development, from weekly thought
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look and join the conversation now. http://goparallel.sourceforge.net/
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https://lists.sourceforge.net/lists/listinfo/ltsp-discuss
For additional LTSP help, try #ltsp channel on irc.freenode.net

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look and join the conversation now. http://goparallel.sourceforge.net/
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