[Xymon] Xymonproxy and an unreachable server

[Jeremy Laidman]

Wim

I suspect the solution is to find and fix the cause of the buffer overflow.
Is there a coredump from which you can get a backtrace?

Another fix might be to put msgcache/xymonfetch into the mix. The msgcache
process queues up queries and delivers them when it can.

Cheers
Jeremy


On 23 February 2018 at 02:31, Wim Nelis <wim.nelis at ziggo.nl> wrote:

> On a Raspberry Pi zero W xymon-client is running to monitor some sensors
> and the PRi0 itself. As the xymon server itself is not reachable by times,
> a minimal xymon-server is running too on the RPi0. Xymonproxy is used to
> distribute the status and data messages to both the local xymon server and
> the primary xymon server. The intention of this setup is to have all the
> RRD's locally complete at the RPi0. If needed, the RRDs can be copied from
> the RPi0 to the primary xymon server.
>
> The local xymon server is listening to port 1985, the xymonproxy to port
> 1984. The latter distributes the messages to two servers, using parameter
> "--server=127.0.0.1:1985,192.168.178.72:1984". This setup is working, but
> the graphs created from the local RRD's contain gaps in the periods that
> the primary xymon server is not reachable. The logfiles of the clients
> running on the RPi0 contain messages like the following, about twice an
> hour:
>
> 2018-02-21 06:10:01.664965 Whoops ! Failed to send message (Connection
> failed)
> 2018-02-21 06:10:01.665673 ->  Could not connect to Xymon
> daemon at 127.0.0.1:1984 (Connection refused)
> 2018-02-21 06:10:01.665767 ->  Recipient '127.0.0.1', timeout 15
> 2018-02-21 06:10:01.665851 ->  1st line: 'status rpi00.mve green Wed
> 2018.02.21 06:10:01'
>
> This does explain the gaps. The logfile of xymonproxy shows that the proxy
> is restarted a dozen times per hour:
>
> 2018-02-21 05:55:38.272757 xymonproxy version 4.3.28 starting
> 2018-02-21 05:55:38.273605 Listening on 0.0.0.0:1984
> 2018-02-21 05:55:38.273751 Sending to Xymon server(s) 127.0.0.1:1985
> 192.168.178.72:1984
> 2018-02-21 05:56:05.304985 Server not responding, message lost
> 2018-02-21 06:00:30.195973 Server not responding, message lost
> 2018-02-21 06:00:36.221908 Server not responding, message lost
> 2018-02-21 06:00:41.231668 Server not responding, message lost
> 2018-02-21 06:00:41.236076 Server not responding, message lost
> *** buffer overflow detected ***: /usr/lib/xymon/server/bin/xymonproxy
> terminated
> 2018-02-21 06:00:42.269357 xymonproxy version 4.3.28 starting
> 2018-02-21 06:00:42.270200 Listening on 0.0.0.0:1984
> 2018-02-21 06:00:42.270346 Sending to Xymon server(s) 127.0.0.1:1985
> 192.168.178.72:1984
> 2018-02-21 06:01:09.301618 Server not responding, message lost
> 2018-02-21 06:05:29.188224 Server not responding, message lost
> 2018-02-21 06:05:40.201194 Server not responding, message lost
> 2018-02-21 06:05:45.208531 Server not responding, message lost
> 2018-02-21 06:05:45.208936 Server not responding, message lost
> 2018-02-21 06:05:45.209058 Server not responding, message lost
> *** buffer overflow detected ***: /usr/lib/xymon/server/bin/xymonproxy
> terminated
> 2018-02-21 06:10:45.237707 xymonproxy version 4.3.28 starting
> 2018-02-21 06:10:45.239061 Listening on 0.0.0.0:1984
> 2018-02-21 06:10:45.239219 Sending to Xymon server(s) 127.0.0.1:1985
> 192.168.178.72:1984
> 2018-02-21 06:11:11.272425 Server not responding, message lost
>
> I have been playing with the queue length, but to no avail. Is it possible
> to have xymonproxy not to terminate every 5 minutes, but just report the
> inability to send a message to a particular server?
>
> Regards,
>   Wim Nelis.
>
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