[Systems] Error on trac reading a bug #4863

[Bernie Innocenti]

On 07/28/2015 06:52 AM, Sam P. wrote:
> Hi Bernie,
> 
> On Tue, Jul 28, 2015 at 2:12 PM Bernie Innocenti <bernie at codewiz.org
> <mailto:bernie at codewiz.org>> wrote:
> 
>     1. We need monitoring for containers health with notifications when
>     parameters go off thresholds. Similar to what Munin does.
> 
> 
> I'm not sure how that would help us.  A container running out of
> resources doesn't crash - parsoid runs almost using all the allocated
> memory and parsoid+trac+others hit their cpu quotas sometimes and just
> keep running.
> 
> Maybe it would be more useful to monitor client metrics, like can we
> reach the service over http?

I wouldn't expect processes to die when they hit their quota of cpu
time, network and disk I/O bandwidth. But the only possible outcome of
an OOM on a Linux system is killing the process group. The reason why is
that most processes are not prepared to handle malloc() returning NULL
and they would just crash or misbehave. Restarting everything is better
than leaving half of the processes limping around in the container in a
crippled state in which all user queries would fail anyway (no database,
no frontend http server...).

When the filesystem fills, the appropriate action depends on whether the
container contains volatile or permanent data. Frontend containers
typically have no local data and can just be restarted from a clean
image. Storage is only used to store logs, coredumps and stuff like that.


>     2. Containers should autorestart if they crash for any reason (with the
>     usual measures to deal with services which crash repeatedly).
> 
> 
> That is a feature built into docker.  I've enabled it in container.yml
> (as a global default) and restarted trac with the new parameters.

Cool.

Hey, thank you very much for being always so responsive in fixing
things. Much appreciated.

> Thanks,
> Sam
>  
> 
> 
>     3. Since high-profile services have been deployed using Docker for a
>     while, software for doing (1) and (2) certainly exists already :-)
> 
> 
>     On 27/07/15 22:32, Samuel Cantero wrote:
>     > I didn't shut it down. The trac container was already off when I
>     checked
>     > it.
>     >
>     > On Mon, Jul 27, 2015 at 9:40 PM, Sam P. <sam at sam.today
>     > <mailto:sam at sam.today <mailto:sam at sam.today>>> wrote:
>     >
>     >     Did you check the logs before you shut it down?
>     >
>     >
>     >     On Tue, 28 Jul 2015 9:38 am Samuel Cantero <scg at sugarlabs.org
>     <mailto:scg at sugarlabs.org>
>     >     <mailto:scg at sugarlabs.org <mailto:scg at sugarlabs.org>>> wrote:
>     >
>     >         Hi Gonzalo,
>     >
>     >         The trac container was down. I just recently turned it on.
>     >
>     >         Somebody turned it off for some reason? If it not the case,
>     >         maybe the container has reached its maximum memory or
>     processor
>     >         limit. The docker container stops in that case.
>     >
>     >         Greetings,
>     >
>     >
>     >
>     >         On Mon, Jul 27, 2015 at 5:01 PM, Gonzalo Odiard
>     >         <godiard at sugarlabs.org <mailto:godiard at sugarlabs.org>
>     <mailto:godiard at sugarlabs.org <mailto:godiard at sugarlabs.org>>> wrote:
>     >
>     >             Today, I get a error
>     >
>     >             502 Bad Gateway
>     >             nginx/1.8.0
>     >
>     >             when try access trac.
>     >
>     >             Gonzalo
>     >
>     >             On Sat, Jul 25, 2015 at 8:40 PM, Gonzalo Odiard
>     >             <godiard at sugarlabs.org <mailto:godiard at sugarlabs.org>
>     <mailto:godiard at sugarlabs.org <mailto:godiard at sugarlabs.org>>> wrote:
>     >
>     >                 Thanks Sams :)
>     >
>     >                 On Sat, Jul 25, 2015 at 3:58 PM, Samuel Cantero
>     >                 <scg at sugarlabs.org <mailto:scg at sugarlabs.org>
>     <mailto:scg at sugarlabs.org <mailto:scg at sugarlabs.org>>> wrote:
>     >
>     >                     Hi All,
>     >
>     >                     I just recently check this email. The good news is
>     >                     that Sam P already dockerized this service and now
>     >                     we have the 1.0.7 Trac version.
>     >
>     >                     Greetings,
>     >
>     >                     On Fri, Jul 24, 2015 at 11:06 AM, Gonzalo Odiard
>     >                     <godiard at sugarlabs.org
>     <mailto:godiard at sugarlabs.org>
>     >                     <mailto:godiard at sugarlabs.org
>     <mailto:godiard at sugarlabs.org>>> wrote:
>     >
>     >                         I am pretty sure dnarvaez updated the trac
>     >                         instance a time ago.
>     >
>     >                         On Fri, Jul 24, 2015 at 12:03 PM, Bernie
>     >                         Innocenti <bernie at codewiz.org
>     <mailto:bernie at codewiz.org>
>     >                         <mailto:bernie at codewiz.org
>     <mailto:bernie at codewiz.org>>> wrote:
>     >
>     >                             On 07/24/2015 10:34 AM, Gonzalo Odiard
>     wrote:
>     >                             > When try to read
>     bughttp://bugs.sugarlabs.org/ticket/4863
>     <http://bugs.sugarlabs.org/ticket/4863>
>     >                             > get the following error:"Genshi
>     UnicodeEncodeError error while rendering
>     >                             > template (unknown template location)"
>     >                             >
>     >                             > A quick google search show this bug [1]
>     >                             >
>     >                             > The error is originated by simply
>     enter a link like this
>     >                             > "<http://trac.edgewall.org/>"
>     >                             > to a ticket. According to this [2]
>     the bug is already solved on Trac 1.0.2
>     >                             >
>     >                             > Then:
>     >                             > Developers: Please don't add links
>     between <> until the error is solved.
>     >                             > Systems: I don't know what version
>     of trac we have running, could be
>     >                             > possible update?
>     >
>     >                             Who's maintaining Trac these days? The
>     wiki
>     >                             points at dnarvaez and me,
>     >                             but the former is MIA and the latter has
>     >                             installed it in 2008 and not
>     >                             touched it ever since:
>     >
>     >                             https://wiki.sugarlabs.org/go/Service/bugs
>     >
>     >                             Perhaps one of the two Sams would like to
>     >                             upgrade Trac in-place or move
>     >                             it into a docker container?
>     >
>     >                             --
>     >                               _ // Bernie Innocenti
>     >                               \X/ http://codewiz.org
>     >
>     >
>     >
>     >
>     >                         --
>     >                         Gonzalo Odiard
>     >
>     >                         SugarLabs - Software [for | by] children
>     learning
>     >
>     >                       
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>     >
>     >
>     >
>     >
>     >                 --
>     >                 Gonzalo Odiard
>     >
>     >                 SugarLabs - Software [for | by] children learning
>     >
>     >
>     >
>     >
>     >             --
>     >             Gonzalo Odiard
>     >
>     >             SugarLabs - Software [for | by] children learning
>     >
>     >
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> 
>     --
>       _ // Bernie Innocenti
>       \X/  http://codewiz.org
> 
> 
> 
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-- 
 _ // Bernie Innocenti
 \X/  http://codewiz.org