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<html><head>
<title>A guide on HOWTO install rsyslog</title>
<meta name="KEYWORDS" content="syslog encryption, rsyslog, stunnel, secure syslog, tcp, reliable, howto, ssl">
</head>
<body>
<h1>HOWTO install rsyslog</h1>
<P><small><i>Written by
<a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer
Gerhards</a></i></small></P>
<h2>Abstract</h2>
<p><i><b>In this paper, I describe how to install
<a href="http://www.rsyslog.com/">rsyslog</a>.</b> It is intentionally a brief
step-by-step guide, targeted to those who want to quickly get it up and running.
For more elaborate information, please consult the rest of the
<a href="manual.html">manual set</a>.</i></p>
<h2>How to make your life easier...</h2>
<p>Some folks have thankfully created <a href="rsyslog_packages.html">
RPMs/packages for rsyslog</a>. If you use them, you can spare yourself many of
the steps below. This is highly recommended if there is a package for your
distribution available.</p>
<h2>Steps To Do</h2>
<p>Rsyslog does currently only have very limited availability as a package (if
you volunteer to create one, <a href="mailto:rgerhards@adiscon.com">drop me a
line</a>). Thus, this guide focuses on installing from the source, which
thankfully is <b>quite easy</b>.</p>
<h3>Step 1 - Download Software</h3>
<p>For obvious reasons, you need to download rsyslog. Load the most recent build
from <a href="http://www.rsyslog.com/downloads">http://www.rsyslog.com/downloads</a>.
Extract the software with "tar xzf -nameOfDownloadSet-". This will create a new
subdirectory rsyslog-version in the current working directory. CD into that. </p>
<p>Depending on your system configuration, you also need to install some build
tools, most importantly make, the gcc compiler and the MySQL development system
(if you intend to use MySQL - the package is often named "mysql-dev"). On many systems, these things should already be
present. If you don't know exactly, simply skip this step for now and see if
nice error messages pop up during the compile process. If they do, you can still
install the missing build environment tools. So this is nothing that you need to
look at very carefully.</p>
<h3>Step 2 - Run ./configure</h3>
<p>Run ./configure to adopt rsyslog to your environment. While doing so, you can
also enable options. Configure will display selected options when it is
finished. For example, to enable MySQL support, run</p>
<p>./configure --enable-mysql</p>
<p>Please note that MySQL support by default is NOT disabled.</p>
<h3>Step 3 - Compile</h3>
<p>That is easy. Just type "make" and let the compiler work. On any recent
system, that should be a very quick task, on many systems just a matter of a few
seconds. If an error message comes up, most probably a part of your build
environment is not installed. Check with step 1 in those cases. </p>
<h3>Step 4 - Install</h3>
<p>Again, that is quite easy. All it takes is a "make install". That will copy
the rsyslogd and the man pages to the relevant directories.</p>
<h3>Step 5 - Configure rsyslogd</h3>
<p>In this step, you tell rsyslogd what to do with received messages. If you are
upgrading from stock syslogd, /etc/syslog.conf is probably a good starting
point. Rsyslogd understands stock syslogd syntax, so you can simply copy over
/etc/syslog.conf to /etc/rsyslog.conf. Note since version 3 rsyslog requires
to load plug-in modules to perform useful work (more about
<a href="v3compatibility.html">compatibilty notes v3</a>). To load the most common plug-ins,
add the following to the top of rsyslog.conf:</p>
<p>
$ModLoad immark # provides --MARK-- message capability
$ModLoad imudp # provides UDP syslog reception
$ModLoad imtcp # provides TCP syslog reception and GSS-API (if compiled to support it)
$ModLoad imuxsock # provides support for local system logging (e.g. via logger command)
$ModLoad imklog # provides kernel logging support (previously done by rklogd)
</p>
Change rsyslog.conf for any further
enhancements you would like to see. For example, you can add database writing as
outlined in the paper "<a href="rsyslog_mysql.html">Writing syslog Data to MySQL</a>"
(remember you need to enable MySQL support during step 2 if you want to do
that!).</p>
<h3>Step 6 - Disable stock syslogd</h3>
<p>In almost all cases, there already is stock syslogd installed. Because both
it and rsyslogd listen to the same sockets, they can NOT be run concurrently. So
you need to disable the stock syslogd. To do this, you typically must change
your rc.d startup scripts.</p>
<p>For example, under <a href="http://www.debian.org/">Debian</a> this must be
done as follows: The default runlevel is 2. We modify the init scripts for
runlevel 2 - in practice, you need to do this for all run levels you will ever
use (which probably means all). Under /etc/rc2.d there is a S10sysklogd script (actually
a symlink). Change the name to _S10sysklogd (this keeps the symlink in place,
but will prevent further execution - effectively disabling it).</p>
<h3>Step 7 - Enable rsyslogd Autostart</h3>
<p>This step is very close to step 3. Now, we want to enable rsyslogd to start
automatically. The rsyslog package contains a (currently small) number of
startup scripts. They are inside the distro-specific directory (e.g. debian). If
there is nothing for your operating system, you can simply copy the stock
syslogd startup script and make the minor modifications to run rsyslogd (the
samples should be of help if you intend to do this).</p>
<p>In our Debian example, the actual scripts are stored in /etc/init.d. Copy the
standard script to that location. Then, you need to add a symlink to it in the
respective rc.d directory. In our sample, we modify rc2.d, and can do this via
the command "ln -s ../init.d/rsyslogd S10rsyslogd". Please note that the S10
prefix tells the system to start rsyslogd at the same time stock sysklogd was
started.</p>
<p><b>Important:</b> if you use the database functionality, you should make sure
that MySQL starts before rsyslogd. If it starts later, you will receive an error
message during each restart (this might be acceptable to you). To do so, either
move MySQL's start order before rsyslogd or rsyslogd's after MySQL.</p>
<h3>Step 8 - Check daily cron scripts</h3>
<p>Most distributions come pre-configured with some daily scripts for log
rotation. As long as you use the same log file names, the log rotation scripts
will probably work quite well. There is one caveat, though. The scripts need to
tell syslogd that the files have been rotated. To do this, they typically have a
part using syslogd's init script to do that. Obviously, the default scripts do
not know about rsyslogd, so they manipulate syslogd. If that happens, in most
cases an additional instance of stock syslogd is started (in almost all cases,
this was not functional, but it is at least distracting). It also means that
rsyslogd is not properly told about the log rotation, which will lead it to
continue to write to the now-rotated files.</p>
<p>So you need to fix these scripts. See your distro-specific documentation how
they are located. Under most Linuxes, the primary script to modify is /etc/cron.daily/sysklogd.
Watch for a comment "Restart syslogd" (usually at the very end of the file). The
restart command must be changed to use rsyslogd's rc script.</p>
<p>Also, if you use klogd together with rsyslogd (under most Linuxes you will do
that), you need to make sure that klogd is restarted after rsyslogd is restarted.
So it might be a good idea to put a klogd reload-or-restart command right after
the rsyslogd command in your daily script. This can save you lots of troubles.</p>
<h3>Done</h3>
<p>This concludes the steps necessary to install rsyslogd. Of course, it is
always a good idea to test everything thoroughly. At a minimalist level, you
should do a reboot and after that check if everything has come up correctly. Pay
attention not only to running processes, but also check if the log files (or the
database) are correctly being populated.</p>
<p>If rsyslogd encounters any serious errors during startup, you should be able
to see them at least on the system console. They might not be in log file, as
errors might occur before the log file rules are in place. So it is always a
good idea to check system console output when things don't go smooth. In some
rare cases, enabling debug logging (-d option) in rsyslogd can be helpful. If
all fails, go to <a href="http://www.rsyslog.com">www.rsyslog.com</a> and check
the forum or mailing list for help with your issue.</p>
<h2>Housekeeping stuff</h2>
<p>This section and its subsections contain all these nice things that you
usually need to read only if you are really curios ;)</p>
<h3>Feedback requested</h3>
<P>I would appreciate feedback on this tutorial. It is still in its infancy, so additional ideas,
comments or bug sighting reports are very welcome. Please
<a href="mailto:rgerhards@adiscon.com">let me know</a> about them.</P>
<h3>Revision History</h3>
<ul>
<li>2005-08-08 *
<a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a> * Initial
version created</li>
<li>2005-08-09 *
<a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a>
* updated to include distro-specific directories, which are now mandatory</li>
<li>2005-09-06 *
<a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a>
* added information on log rotation scripts</li>
<li>2007-07-13 *
<a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a>
* updated to new autotools-based build system</li>
</ul>
<h3>Copyright</h3>
<p>Copyright (c) 2005, 2007
<a href="http://www.adiscon.com/en/people/rainer-gerhards.php">Rainer Gerhards</a> and
<a href="http://www.adiscon.com/en/">Adiscon</a>.</p>
<p> Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license can be viewed at
<a href="http://www.gnu.org/copyleft/fdl.html">
http://www.gnu.org/copyleft/fdl.html</a>.</p>
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