[syslog-ng] disk-buffer in elasticsearch2 destination loses messages if docker container is killed
Budai, László
laszlo.budai at oneidentity.com
Mon Sep 17 12:31:57 UTC 2018
Hi,
I'll try to reproduce this issue in my test environment.
What syslog-ng version do you have?
L.
On Mon, Sep 17, 2018 at 2:04 PM, Jose Angel Santiago <jasantiago at stratio.com
> wrote:
> Hi,
>
> After repeating the test without TLS between syslog-agent & syslog-relay,
> with 2229 messages logged with a 20 msgs/sec logging ratio, in debug mode
> and with two tcpdumps running, these are the conclussions:
>
> - Syslog-agent sends every single message (checked with tcpdump file and
> syslog-agent log file)
> - Syslog-relay returns ACK for every single message, but sometimes the
> package contains more than one message (checked with tcpdump file)
> - Checking the syslog-relay log after killing & starting the docker
> container, I found the trace 'Reliable disk-buffer state loaded;
> filename='/syslog-ng-00000.rqf', queue_length='99', size='173844' and the
> queued messages (from msg 236 to msg 334 are processed). The next message
> processed is the nº 440. and it comes from the active network destination
> again.
> - Once all logs have been processed, in elasticsearch (syslog-relay
> destination) I can find messages from 1 to 334, and messages from 440 to
> 2229.
>
> How is it possible that syslog-relay returns ACK for messages 335 to 439
> to syslog-agent, but they are not in the queue, nor in the .rqf file? Where
> did these messages go? I know they are sent before starting to fill
> syslog-agent disk-buffer file (checked with rqf file from syslog-agent when
> I kill the syslog-relay container). It seems that there's some kind of race
> condition that makes those messages are not processed/queued while
> syslog-relay is being killed.
>
> Mi procedure consists of:
>
> . Start tcpdump on both syslog-agent & syslog-relay hosts
> - Start logger process
> - Once logs are being inserted in elasticsearch, I kill the syslog-relay
> docker container, wait about 10 seconds, and run a new container (using a
> mapped volume where .rqf file and .persist file are)
> - Once logs are being inserted in elasticsearch again, I stop the logger
> process.
> - I wait until no log is left to be processed
>
> Would you test anything else? I'm running out of ideas.
>
> PD: Same test with logger process writing 5 msgs/sec ratio produces from 0
> to 5 lost messages.
>
> Regards.
>
>
>
>
> 2018-09-14 14:05 GMT+02:00 Jose Angel Santiago <jasantiago at stratio.com>:
>
>> Hi,
>>
>> I've got more accurate information about where are my lost messages.
>>
>> Now I'm using disk-buffer in syslog-agent and syslog-relay, and I've
>> checked that lost messages are the ones sent by the syslog-agent when the
>> syslog-relay docker container is being killed. I can see those messages on
>> syslog-agent log (I've got both agent & relay in debug mode) with its
>> corresponding "Outgoing message" line, but those messages never reach the
>> relay.
>>
>> Could it be that the relay docker container still returns ACK to the
>> agent (the agent resolves relay fqdn with a custom DNS) while syslog-ng
>> process within the container is being stopped? I'm about to test again
>> using tcpdump to confirm this theory,
>>
>> BTW, disk-buffers works ok, sometimes I get some duplicated messages when
>> restarting the relay but that's not a problem for me. Forget about my
>> .persist file re-creation theory, it doesn't happen.
>>
>> Regards.
>>
>>
>>
>> 2018-09-13 18:07 GMT+02:00 Péter, Kókai <peter.kokai at oneidentity.com>:
>>
>>> Hello,
>>>
>>> It would not make sense to replace the persist file after restart, so it
>>> is not something that syslog-ng does. Only if that file is corrupted, in
>>> that case at startup there should be a log about it, have you checked the
>>> syslog-ng logs ? (it would be better to enable debug and/or verbose logs,
>>> and if possible share it with us.)
>>>
>>> Could you reproduce the same behavior without docker (if possible) ?
>>>
>>>
>>>
>>> Best Regards,
>>> Peter Kokai
>>>
>>> On Thu, Sep 13, 2018 at 4:44 PM Jose Angel Santiago <
>>> jasantiago at stratio.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> I guess I know what is happening, when I start from scratch the docker
>>>> container, even I provide a persist file and a buffer file within the
>>>> mapped volume, syslog-ng recreates them so all messages in buffer file
>>>> which were not processed by the relay are lost.
>>>>
>>>> Is there any way to tell syslog-ng to use an already existing .persist
>>>> file so it doesn't recreate the .rqf file?
>>>>
>>>> Regards.
>>>>
>>>>
>>>>
>>>> 2018-09-13 16:23 GMT+02:00 Budai, László <laszlo.budai at oneidentity.com>
>>>> :
>>>>
>>>>> Hi,
>>>>>
>>>>> one problem could be if the flush-limit would be greater than 1... in
>>>>> that case syslog-ng would use a HttpBulkMessageProcessor.
>>>>> In this case syslog-ng pass the message to the
>>>>> HttpBulkMessageProcessor and sends back a positive ACK to the LogSource (so
>>>>> the message is removed from the diskbuffer), and if the dockerimage is
>>>>> killed, all the messages stored in the HttpBulkMessageProcessor are lost.
>>>>> But in your case syslog-ng should use the
>>>>> HttpSingleMessageProcessor... which means that the messages are sent
>>>>> one-by-one...
>>>>> Could you check the diskbuffer with the dqtool?
>>>>>
>>>>>
>>>>> L.
>>>>>
>>>>> On Thu, Sep 13, 2018 at 3:50 PM, Jose Angel Santiago <
>>>>> jasantiago at stratio.com> wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I'm running syslog-ng (with an elasticsearch2 destination configured)
>>>>>> within a docker container, and I'm trying to avoid loss of messages if I
>>>>>> kill the docker container and I start it again.
>>>>>>
>>>>>> This is my scenary:
>>>>>>
>>>>>> - A service which produces 20 lines of log per second
>>>>>> - A sislog-ng instance reading from a wildcard-file source (but
>>>>>> actually it only reads logs from the above service, let's call it
>>>>>> syslog-agent), which sends all logs to another syslog-ng instance (the one
>>>>>> running in a docker container, let's call it syslog-relay) though a network
>>>>>> destination.
>>>>>> - The syslog-relay sends messages to an elasticsearch instance, with
>>>>>> following configuration:
>>>>>>
>>>>>> options {
>>>>>> chain-hostnames(no);
>>>>>> use-dns(no);
>>>>>> keep-hostname(yes);
>>>>>> owner("syslog-ng");
>>>>>> group("stratio");
>>>>>> perm(0640);
>>>>>> time-reap(30);
>>>>>> mark-freq(10);
>>>>>> stats-freq(0);
>>>>>> bad-hostname("^gconfd$");
>>>>>> flush-lines(100);
>>>>>> log-fifo-size(1000);
>>>>>> };
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> *destination d_elastic_default_0 { elasticsearch2(
>>>>>> cluster("myelastic") cluster-url("https://myelastic.logs:9200
>>>>>> <https://myelastic.logs:9200>") client_mode("https")
>>>>>> index("default") type("log") flush-limit(1)
>>>>>> disk-buffer( mem-buf-size(16M)
>>>>>> disk-buf-size(16M) reliable(yes)
>>>>>> dir("/syslog-ng/log") ) http-auth-type("clientcert")
>>>>>> java-keystore-filepath("/etc/syslog-ng/certificates/syslog-relay.jks")
>>>>>> java-keystore-password("XXXXXX")
>>>>>> java-truststore-filepath("/etc/syslog-ng/certificates/ca-bundle.jks")
>>>>>> java-truststore-password("XXXXXXXXXX") );};*
>>>>>>
>>>>>> - The dir "/syslog-ng/log" is mapped to a path "/tmp/buffer" from the
>>>>>> host where the docker container is running, so when I kill the docker
>>>>>> container, the buffer file is not lost.
>>>>>> - I've set flush-limit to 1 because I thought that I may lost 1
>>>>>> message only as much.
>>>>>>
>>>>>> This architecture is working fine (flush-limit=1 makes very slow, but
>>>>>> for this test is ok), but if I kill the syslog-relay docker container, wait
>>>>>> 5 to 10 seconds and start it again from scratch, I can see that several
>>>>>> hundreds of logs are missing in elasticsearch. I check it by stopping the
>>>>>> logger service and letting syslog-ng agent & relay to finish the process
>>>>>> enqueued messages.
>>>>>>
>>>>>> I can see in the syslog-agent stats that all logs messages have been
>>>>>> processed, so it seems the problem is on the syslog-relay.
>>>>>>
>>>>>> Is this behaviour expected? If so, how can I protect against loss of
>>>>>> messages in case of a syslog-relay docker container unexpected kill?
>>>>>>
>>>>>> Thanks in advance.
>>>>>>
>>>>>>
>>>>>> --
>>>>>>
>>>>>> | Jose Angel Santiago
>>>>>>
>>>>>> [image: Logo_signature2.png] <http://www.stratio.com/>
>>>>>>
>>>>>> Vía de las dos Castillas, 33, Ática 4, 3ª Planta
>>>>>>
>>>>>> 28224 Pozuelo de Alarcón, Madrid, Spain
>>>>>>
>>>>>> +34 918 286 473 <+34%20918%2028%2064%2073> | www.stratio.com
>>>>>> <https://twitter.com/stratiobd>
>>>>>> <https://www.linkedin.com/company/stratiobd>
>>>>>> <https://www.youtube.com/c/StratioBD>
>>>>>>
>>>>>> ____________________________________________________________
>>>>>> __________________
>>>>>> Member info: https://lists.balabit.hu/mailman/listinfo/syslog-ng
>>>>>> Documentation: http://www.balabit.com/support
>>>>>> /documentation/?product=syslog-ng
>>>>>> FAQ: http://www.balabit.com/wiki/syslog-ng-faq
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> ____________________________________________________________
>>>>> __________________
>>>>> Member info: https://lists.balabit.hu/mailman/listinfo/syslog-ng
>>>>> Documentation: http://www.balabit.com/support
>>>>> /documentation/?product=syslog-ng
>>>>> FAQ: http://www.balabit.com/wiki/syslog-ng-faq
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> | Jose Angel Santiago
>>>>
>>>> [image: Logo_signature2.png] <http://www.stratio.com/>
>>>>
>>>> Vía de las dos Castillas, 33, Ática 4, 3ª Planta
>>>>
>>>> 28224 Pozuelo de Alarcón, Madrid, Spain
>>>>
>>>> +34 918 286 473 <+34%20918%2028%2064%2073> | www.stratio.com
>>>> <https://twitter.com/stratiobd>
>>>> <https://www.linkedin.com/company/stratiobd>
>>>> <https://www.youtube.com/c/StratioBD>
>>>> ____________________________________________________________
>>>> __________________
>>>> Member info: https://lists.balabit.hu/mailman/listinfo/syslog-ng
>>>> Documentation: http://www.balabit.com/support
>>>> /documentation/?product=syslog-ng
>>>> FAQ: http://www.balabit.com/wiki/syslog-ng-faq
>>>>
>>>>
>>> ____________________________________________________________
>>> __________________
>>> Member info: https://lists.balabit.hu/mailman/listinfo/syslog-ng
>>> Documentation: http://www.balabit.com/support
>>> /documentation/?product=syslog-ng
>>> FAQ: http://www.balabit.com/wiki/syslog-ng-faq
>>>
>>>
>>>
>>
>>
>> --
>>
>> | Jose Angel Santiago
>>
>> [image: Logo_signature2.png] <http://www.stratio.com/>
>>
>> Vía de las dos Castillas, 33, Ática 4, 3ª Planta
>>
>> 28224 Pozuelo de Alarcón, Madrid, Spain
>>
>> +34 918 286 473 | www.stratio.com
>> <https://twitter.com/stratiobd>
>> <https://www.linkedin.com/company/stratiobd>
>> <https://www.youtube.com/c/StratioBD>
>>
>
>
>
> --
>
> | Jose Angel Santiago
>
> [image: Logo_signature2.png] <http://www.stratio.com/>
>
> Vía de las dos Castillas, 33, Ática 4, 3ª Planta
>
> 28224 Pozuelo de Alarcón, Madrid, Spain
>
> +34 918 286 473 | www.stratio.com
> <https://twitter.com/stratiobd>
> <https://www.linkedin.com/company/stratiobd>
> <https://www.youtube.com/c/StratioBD>
>
> ____________________________________________________________
> __________________
> Member info: https://lists.balabit.hu/mailman/listinfo/syslog-ng
> Documentation: http://www.balabit.com/support/documentation/?
> product=syslog-ng
> FAQ: http://www.balabit.com/wiki/syslog-ng-faq
>
>
>
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