[syslog-ng] a log message is output in the two line

Scheidler, Balázs balazs.scheidler at balabit.com
Wed Jun 29 07:59:17 CEST 2016


Are you absolutely sure, that syslog-ng is reading the config file where
you set log-msg-size() to 8192? Maybe you should try to generate a syntax
error on purpose and see if it fails to start up. Sometimes people have
multiple configs on their system.

Or just supply the -f option to syslog-ng that tells syslog-ng where to
find its configuration explicitly.

You can also set log-msg-size() on a per source basis, if I remember
correctly.

-- 
Bazsi

On Mon, Jun 27, 2016 at 12:26 PM, Hirose, Shinsaku <
hirose.shinsaku at jp.fujitsu.com> wrote:

> Dear Scheidler
>
> Thanks for your response!
>
> I tried debug mode.
>
> I saw that client received  two "Incoming message".
> As you said, the client is looked like being the culprit.
>
> I think my hope is difficult for my skill.....
> So I will try to find the another solutoion.
>
> I am graceful for your advices!
>
> Best regards,
>
>
>
> -----Original Message-----
> From: syslog-ng-bounces at lists.balabit.hu [mailto:
> syslog-ng-bounces at lists.balabit.hu] On Behalf Of Scheidler, Balazs
> Sent: Saturday, June 25, 2016 5:06 AM
> To: Syslog-ng users' and developers' mailing list <
> syslog-ng at lists.balabit.hu>
> Subject: Re: [syslog-ng] a log message is output in the two line
>
> For some reason the log-msg-size() setting wasn't effective. Clearly
> syslog-ng split the line at 8192 bytes. It could either be the client or
> the server, but I would vote for the client being the culprit.
>
> syslog-ng emits a debug message that starts like: "Incoming message",
> there you should see what was received as a single entry. My guess is that
> you'll see the line split there.
>
> This way you can pinpoint which one is the culprit (the client or the
> server).
>
> On Jun 24, 2016 11:41 AM, "Hirose, Shinsaku" <
> hirose.shinsaku at jp.fujitsu.com <mailto:hirose.shinsaku at jp.fujitsu.com> >
> wrote:
>
>
>         Dear Sandor
>
>         Thank you for your quick responce.
>
>         > UDP transport limits datagram size to 64k
>
>         OK. Thanks!
>
>         I raised log_msg_size to higer value.
>         But the behavior did not changed.
>
>         I added ' log_msg_size (16384);' in options on the two hosts.
>         ------------------------------------------------------------
>         options {
>                 flush_lines (0);
>                 time_reopen (10);
>                 log_fifo_size (1000);
>                 long_hostnames (off);
>                 use_dns (no);
>                 use_fqdn (no);
>                 create_dirs (no);
>                 keep_hostname (yes);
>                 log_msg_size (16384);
>         };
>         ------------------------------------------------------------
>
>         And I did restarting service.
>         But the behavior did not changed.
>
>         Do you know this reason?
>
>         Best regards,
>
>
>
>
>         -----Original Message-----
>         From: syslog-ng-bounces at lists.balabit.hu <mailto:
> syslog-ng-bounces at lists.balabit.hu>  [mailto:
> syslog-ng-bounces at lists.balabit.hu <mailto:
> syslog-ng-bounces at lists.balabit.hu> ] On Behalf Of Sandor Geller
>         Sent: Friday, June 24, 2016 11:32 PM
>         To: syslog-ng at lists.balabit.hu <mailto:syslog-ng at lists.balabit.hu>
>         Subject: Re: [syslog-ng] a log message is output in the two line
>
>         Hi,
>
>         On 06/24/2016 04:10 PM, Hirose, Shinsaku wrote:
>         > Hello, all,
>         >
>         > I use syslog-ng-3.2.5-4.el6.x86_64 on Centos6.
>         > I got it from eple epel repository.
>         >
>         > I am troubled in how to use the source file driver.
>         > The touble is that a log message is output in the two lines on
> remote syslog server.
>         >
>         > How to reproduce is followings.
>         >
>         > 1. Prepare two hosts running syslog-ng.
>         >
>         >    Host_A configuration is followings.
>         >    ----------------------------------------
>         >    source test {
>         >      file("/tmp/a.log");
>         >    };
>         >    destination d_remote { udp("192.168.0.2"); };
>         >    log { source(test); destination(d_remote); };
>         >    ----------------------------------------
>
>         UDP transport limits datagram size to 64k
>
>         >    Host_B(192.168.0.2) configuration is defaults.
>         >
>         > 2.Execute following command on Host_A.
>         >
>         >    $ seq 8193 | (xargs -i echo -n "a";echo "") >> /tmp/a.log
>         >
>         > 3.Check the log on Host_B.
>         >
>         >    As the result, a log message is output in the two lines on
> Host_B.
>         >
>         >    One line is following. The num of "a" is 8192.
>         >    aaaaaaaaaaaaa.......
>         >
>         >    The other line is following. The num of "a" is 1.
>         >    a
>         >
>         > I hope a log message is output in the one line on Host_B.
>         > Is my hope readily achievable?
>
>
>         syslog isn't rsync so the syslog standards must get taken into
> account.
>         Original syslog was designed to work with single-line, small
> messages (up to 1k) fitting into a single UDP packet to avoid fragmentating
> the datagram.
>
>         IIRC the maximal message size in syslog-ng defaults to 8192 bytes,
> so from stream-like sources input will be splitted when this length is
> reached.
>
>         > Please advise me.
>
>         You can raise log_msg_size to higer value but don't expect that
> values larger than 64k will work with the udp() transport. You should
> switch to another transport driver like tcp() or even better to syslog()
>
>         Regards,
>
>         Sandor
>
>
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>
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>
>
>
>
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