[syslog-ng] disk-buffer in elasticsearch2 destination loses messages if docker container is killed
Jose Angel Santiago
jasantiago at stratio.com
Mon Sep 17 12:33:17 UTC 2018
3.17.2
Thanks in advance.
2018-09-17 14:31 GMT+02:00 Budai, László <laszlo.budai at oneidentity.com>:
> 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
>>
>>
>>
>
> ____________________________________________________________
> __________________
> 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>
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