<div dir="ltr"><div>> the real question is why does it work in RHEL and fail in UBUNTU?</div><div><br></div><div>The difference might come from that you are using different versions of syslog-ng on the two systems:</div><div><div>> UBUNTU - </div><div>> syslog-ng 3.5.6</div></div><div>> RHEL<br></div><div>> syslog-ng 3.3.5</div><div><br></div><div>> The constant name is needed because I obviously cannot keep changing
the syslog-ng configuration to match the day's localhost log file name.</div><div><br></div><div>You can avoid such hack. Please check the recent addition to syslog-ng: wildcard filesource. You need to upgrade to 3.16 though.</div><div><a href="https://syslog-ng.com/documents/html/syslog-ng-ose-latest-guides/en/syslog-ng-ose-guide-admin/html/reference-source-wildcard-file.html">https://syslog-ng.com/documents/html/syslog-ng-ose-latest-guides/en/syslog-ng-ose-guide-admin/html/reference-source-wildcard-file.html</a><br></div>
</div><br><div class="gmail_quote"><div dir="ltr">On Sun, Jul 1, 2018 at 5:26 AM Evan Rempel <<a href="mailto:erempel@uvic.ca">erempel@uvic.ca</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I suspect it is more related to the filesystem and options.<br>
<br>
1. Are you using a different fileystem (xfs vs ext3 or NFS)<br>
2. Are there different mount options for the filesystem?<br>
<br>
Evan.<br>
<br>
On 06/30/2018 08:21 PM, Donatello D wrote:<br>
> @Jim - this is what i use as a workaround already, but it is<br>
> sub-optimal, as there will be other files that are rolled over in<br>
> different intervals, so i end up reloading config multiple times.<br>
><br>
> the real question is why does it work in RHEL and fail in UBUNTU?<br>
><br>
><br>
>> Date: Sat, 30 Jun 2018 20:31:59 -0400<br>
>> From: Jim Hendrick <<a href="mailto:james.r.hendrick@gmail.com" target="_blank">james.r.hendrick@gmail.com</a>><br>
>> To: "Syslog-ng users' and developers' mailing list"<br>
>> <<a href="mailto:syslog-ng@lists.balabit.hu" target="_blank">syslog-ng@lists.balabit.hu</a>><br>
>> Subject: Re: [syslog-ng] syslog-ng not following symlinks correctly on<br>
>> UBUNTU, works fine in RHEL<br>
>> Message-ID:<br>
>> <CANEn2idABV25G1vFa4B=<a href="mailto:WhOyuHjd3HwLMKFBHgqydH6zvH0H9w@mail.gmail.com" target="_blank">WhOyuHjd3HwLMKFBHgqydH6zvH0H9w@mail.gmail.com</a>><br>
>> Content-Type: text/plain; charset="utf-8"<br>
>><br>
>> hardlinks are simply additional pointers to the same inode.<br>
>> symlinks contain the name of the referenced object<br>
>><br>
>> If you want a hack - maybe have syslog-ng reload after the file changes?<br>
>> (SIGHUP)<br>
>><br>
>><br>
>><br>
>> On Sat, Jun 30, 2018 at 12:56 PM, Ankit Agarwal <<a href="mailto:ankit@travelmyheart.org" target="_blank">ankit@travelmyheart.org</a>><br>
>> wrote:<br>
>><br>
>>> Hi,<br>
>>><br>
>>> I ran into a similar problem on Ubuntu as well.<br>
>>><br>
>>> In my case, I was tracking the Tomcat localhost log file in syslog-ng but<br>
>>> Tomcat creates a new log file everyday by default, and the filename changes<br>
>>> (since it includes the date).<br>
>>><br>
>>> Therefore, I periodically created a softlink to the localhost log file<br>
>>> where the link had a constant name. The constant name is needed because I<br>
>>> obviously cannot keep changing the syslog-ng configuration to match the<br>
>>> day's localhost log file name.<br>
>>><br>
>>> I found that the softlink did not work.<br>
>>><br>
>>> Instead I had to create a hardlink.<br>
>>><br>
>>> This is because the softlink's modified date does not change when the<br>
>>> underlying file changes. The hardlink's modified date does change since it<br>
>>> is pointing to the actual data. We need the modified date to change for the<br>
>>> syslog-ng client to pick up new log entries.<br>
>>><br>
>>> In my case, I periodically ran the following command via CRON in the<br>
>>> Tomcat logs directory:<br>
>>><br>
>>> sudo ln -f $(ls -t localhost.* | head -1) tomcat_localhost.log<br>
>>><br>
>>> This is to get the latest localhost log file and create the hardlink for<br>
>>> it (overwriting the older hardlink that may have been pointing to the<br>
>>> previous day's localhost log file).<br>
>>><br>
>>> I ran this every hour just to be safe.<br>
>>><br>
>>><br>
>>> So in your case, I think you would just need to recreate the hardlink as<br>
>>> soon as your log file is rotated.<br>
>>><br>
>>><br>
>>> Hope this helps.<br>
>>><br>
>>> Ankit<br>
>>><br>
>>><br>
>>><br>
>>> ---- On Sat, 30 Jun 2018 01:13:44 -0700 *Donatello D<br>
>>> <<a href="mailto:bluray.vik@gmail.com" target="_blank">bluray.vik@gmail.com</a> <<a href="mailto:bluray.vik@gmail.com" target="_blank">bluray.vik@gmail.com</a>>>* wrote ----<br>
>>><br>
>>> syslog-ng is configured to read a symlink pointing to logs generated from<br>
>>> my application which rotates the file using log4j2 rollingfile appender.<br>
>>> Everything works fine till the rotation happens. after the file get rotated<br>
>>> syslog-ng still seems to hold on to the older inode (which is not moved)<br>
>>> and doesn't change to follow the new logs. this however does not happen in<br>
>>> RHEL where syslog-ng recognizes the file is now rotated and moves to the<br>
>>> new file. In both cases the sym link is always configured to point to the<br>
>>> latest file. version details and logs from both OSs below.<br>
>>><br>
>>> What am i missing here?<br>
>>><br>
>>> UBUNTU -<br>
>>> syslog-ng 3.5.6<br>
>>> Installer-Version: 3.5.6<br>
>>> Revision: 3.5.6-2.1 [@416d315] (Ubuntu/16.04)<br>
>>> Compile-Date: Oct 24 2015 03:49:19<br>
>>> Available-Modules: afsocket,afuser,tfgeoip,confgen,csvparser,<br>
>>> syslogformat,afamqp,redis,afsql,affile,afsmtp,linux-<br>
>>> kmsg-format,dbparser,system-source,cryptofuncs,basicfuncs,<br>
>>> json-plugin,afprog,afsocket-tls,afstomp,afsocket-notls,afmongodb<br>
>>> Enable-Debug: off<br>
>>> Enable-GProf: off<br>
>>> Enable-Memtrace: off<br>
>>> Enable-IPv6: on<br>
>>> Enable-Spoof-Source: on<br>
>>> Enable-TCP-Wrapper: on<br>
>>> Enable-Linux-Caps: on<br>
>>> Enable-Pcre: on<br>
>>><br>
>>> symlink is pointing to the file that gets the logs. prior to rotation the<br>
>>> process watches correctly for the file (same inodes held by my app and<br>
>>> syslog-ng)<br>
>>><br>
>>> lrwxrwxrwx 1 root root 56 Jun 29 08:44 node1-access.log -><br>
>>> /x/logs/vik-test_access.log<br>
>>><br>
>>> COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME<br>
>>> java 11032 vikram 53w REG 8,1 1101 1542626<br>
>>> vik-test_access.log<br>
>>> syslog-ng 21661 root 9r REG 8,1 1101 1542626<br>
>>> vik-test_access.log<br>
>>><br>
>>><br>
>>> Post rotation, syslog-ng holds on to the older file (now rotated).<br>
>>><br>
>>> COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME<br>
>>> java 11032 vikram 53w REG 8,1 876 1542631<br>
>>> e/elasticsearch-6.2.3/logs/vik-test_access.log<br>
>>> syslog-ng 21661 root 9r REG 8,1 1101 1542626<br>
>>> e/elasticsearch-6.2.3/logs/vik-test_access-2018-06-30.log<br>
>>><br>
>>> The same setup works perfectly fine in RHEL (version details below) where<br>
>>> syslog-ng follows the new file correctly.<br>
>>><br>
>>> RHEL<br>
>>> syslog-ng 3.3.5<br>
>>> Installer-Version: 3.3.5<br>
>>> Revision: ssh+git://bazsi@git.balabit//var/scm/git/syslog-ng/syslog-<br>
>>> ng-ose--mainline--3.3--master#d5d607c05251b38e821efe27bc46ac8db78dd722<br>
>>> Compile-Date: Oct 18 2012 15:17:09<br>
>>> Default-Modules: affile,afprog,afsocket,afuser,<br>
>>> basicfuncs,csvparser,dbparser,syslogformat<br>
>>> Available-Modules: afprog,afsocket-tls,dbparser,confgen,convertfuncs,<br>
>>> basicfuncs,afsocket,afmongodb,csvparser,affile,dummy,syslogformat,afuser<br>
>>> Enable-Debug: off<br>
>>> Enable-GProf: off<br>
>>> Enable-Memtrace: off<br>
>>> Enable-IPv6: on<br>
>>> Enable-Spoof-Source: off<br>
>>> Enable-TCP-Wrapper: on<br>
>>> Enable-Linux-Caps: off<br>
>>> Enable-Pcre: on<br>
>>><br>
>>><br>
<br>
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</blockquote></div>