MRTG 系列连载-2 : Unix Guide

ailms

mrtg-unix-guide

Description
MRTG comes to you in Source Code. This means
that you have to compile parts of it before you can use it on a Unix machine.
These instructions help you to do so.

# 注释 ：MRTG
是以源代码方式发布的，这就意味着必须进行编译


Preparation

In order to compile and use mrtg you need a C
compiler and a copy of perl installed on your machine. In most cases this will
already be available. In case it is not, here are some starting points. Below
I'll give you a detailed run through the whole compilation
process.
GCC
The GNU C compiler comes preinstalled on most of
the free Unicies out there. For commercial derivatives you may have to download
and compile it first. If you have no compiler at all there is a chicken and egg
problem, but there are also precompiled versions of gcc available for most
operating systems.

http://gcc.gnu.org/
Perl
Large parts of the MRTG system are written in
the Perl scripting language. Make sure there is a recent copy of perl on your
machine (try perl -v). At least version 5.005 is required for mrtg to work well.
You can get the latest perl from

http://www.perl.com/

MRTG generates traffic graphs in the PNG format.
To be able to do this it needs several 3rd party libraries. When compiling these
libraries I urge you to make sure you compile them as static libraries.
There is just much less trouble ahead if you are doing it like this. See the
Instructions in the next section for inspiration. Note that many free unices
have all the required libraries already in place so there is no need to install
another copy. To check it is best to skip all the library instructions below and
go straight into the mrtg compile.
If the first attempt fails and you do not get a
working version of mrtg, try compiling new copies of all libraries as explained
below. Do this BEFORE you send email to me about problems compiling
mrtg.

gd
This is a basic graph drawing library created by
Thomas Boutell. Note that all releases after Version 1.3 only create PNG images.
This is because a) Thomas got into trouble because the GIF format which it used
to produce uses a compression technology patented by Unisys. b) PNG is more
efficient and patent free. MRTG can work with old and new version of the GD
library. You can get a recent copy of GD from:

http://www.boutell.com/gd/
libpng
Is required by gd in order to produce PNG
graphics files. Get it from:

http://www.libpng.org/pub/png/libpng.html
zlib
Is needed by libpng to compress the graphics
files you create. Get a copy from

http://www.gzip.org/zlib

And last but not least you also need mrtg
itself. In case you have not yet downloaded it, you can find a copy on my
website:

http://oss.oetiker.ch/mrtg/pub

Library compilation

In this section I will give you step by step
instructions on how to compile the various libraries required for the
compilation of mrtg. Note that these libaries may already be installed if you
have a *BSD or Linux system so you can skip recompiling them. The
wget program used below is a simple web downloader. You can also enter
the address into your netscape if you don't have wget
available.
First let's create a directory for the
compilation. Note that this may already exist on your system. No problem, just
use it.

mkdir -p
/usr/local/src
cd
/usr/local/src

If you do not have zlib
installed:

wget
http://www.gzip.org/zlib/zlib-1.1.4.tar.gz
gunzip -c zlib-*.tar.gz | tar xf
-
rm
zlib-*.tar.gz
mv zlib-*
zlib
cd zlib
./configure
make
cd ..

If you don't have libpng
installed

wget
http://public.planetmirror.com/pub/sourceforge/l/li/libpng/libpng-1.0.15.tar.gz
gunzip -c libpng-*.tar.gz |tar xf
-
rm
libpng-*.tar.gz
mv libpng-*
libpng
cd libpng
make -f scripts/makefile.std CC=gcc
ZLIBLIB=../zlib ZLIBINC=../zlib
rm *.so.*
*.so
cd ..

And now you can compile
gd

For versions up to 1.8.4,
try:
wget
http://www.boutell.com/gd/http/gd-1.8.4.tar.gz
gunzip -c gd-*.tar.gz |tar xf
-
rm
gd-*.tar.gz
mv gd-* gd
cd gd

The \ characters at the end of the following
lines mean that all the following material should actually be written on a
single line.

perl -i~
-p -e s/gd_jpeg.o//g Makefile            
make INCLUDEDIRS="-I. -I../zlib -I../libpng"
\
     
LIBDIRS="-L../zlib -L. -L../libpng" \
     
LIBS="-lgd -lpng -lz -lm" \
     
CFLAGS="-O -DHAVE_LIBPNG"
cd ..

For version starting around 2.0.11,
try:

wget
http://www.boutell.com/gd/http/gd-2.0.11.tar.gz
gunzip -c gd-2.0.11.tar.gz |tar xf
-
mv gd-2.0.11
gd
cd gd
env CPPFLAGS="-I../zlib -I../libpng"
LDFLAGS="-L../zlib -L../libpng" ./configure --disable-shared
\
   
--without-freetype --without-jpeg
make
cp .libs/*
.

Mrtg compilation

Ok, now everything is ready for the mrtg
compilation.

cd
/usr/local/src
gunzip -c mrtg-2.14.6.tar.gz | tar xvf
-
cd
mrtg-2.14.6

If all the libraries have been preinstalled on
your system you can configure mrtg by doing a simple:

./configure
--prefix=/usr/local/mrtg-2

Otherwise you may have to give some hints on
where to find the various libraries required to compile
mrtg:

./configure --prefix=/usr/local/mrtg-2       \
            
--with-gd=/usr/local/src/gd      
\
            
--with-z=/usr/local/src/zlib     
\
            
--with-png=/usr/local/src/libpng

If you have RRDtool available you might want to tell
mrtg about it so that you can opt to use rrdtool with mrtg. Check
the mrtg-rrd manpage
.
Configure will make sure your environment is fit
for building mrtg. If it finds a problem, it will tell you so and it will also
tell you what to do about it. If everything is OK, you will end up with a custom
Makefile for your system. Now type:

make

This builds the rateup binary and edits all the
perl pathnames in the scripts. You can now install mrtg by
typing

make install   
(requires gnu install)

All the software required by MRTG is now
installed under the /usr/local/mrtg-2
subdirectory.
You can now safely delete the libraries we
compiled above. Then again, you might want to keep them around so that you have
them available when compiling the next version of mrtg.

Configuration

The next step is to configure mrtg for
monitoring a network device. This is done by creating an mrtg.cfg file
which defines what you want to monitor. Luckily, you don't have to dive straight
in and start writing your own configuration file all by yourself. Together with
mrtg you also got a copy of cfgmaker. This is a script you can point at a
router of your choice; it will create a mrtg configuration file for you. You can
find the script in the bin subdirectory.

cfgmaker --global 'WorkDir:
/home/httpd/mrtg'  
\
         
--global 'Options[_]: bits,growright'
\
         
--output /home/mrtg/cfg/mrtg.cfg   
\
         
community@router.abc.xyz

This example above will create an mrtg config file in
/home/mrtg/cfg assuming this is a directory visible on your webserver.
You can read all about cfgmaker in
the cfgmaker manpage
. One area you might want to look at is the possibility of
using --ifref=ip to prevent interface renumbering troubles from catching
you.
If you want to start rolling your own mrtg
configuration files, make sure you read
the mrtg-reference manpage
to learn all about the possible configuration
options.

Running mrtg

Once you have created a configuration file, try
the following:

/usr/local/mrtg-2/bin/mrtg
/home/mrtg/cfg/mrtg.cfg

This will query your router and also create your
first mrtg trafic graphs and webpages. When you run mrtg for the first time
there will be a lot of complaints about missing log files. Don't worry, this is
normal for the first 2 times you start mrtg. If it keeps complaining after this
time you might want to look into the
problem.
Starting mrtg by hand is not ideal in the long
run. So when you are satisfied with the results you can automate the process of
running mrtg in regular intervals (this means every 5 minutes by
default).
You can either add mrtg to your crontab with a
line like this:

0,5,10,15,20,25,30,35,40,45,50,55 * * * *
\
      
/mrtg /mrtg.cfg
\
               
--logging /var/log/mrtg.log

or if you
live in Linux Land the line may look like this if you are using crontab
-e

*/5 * * * *  
/mrtg /mrtg.cfg
\
                      --logging
/var/log/mrtg.log

or like this if you use
/etc/crontab

*/5 * * * *  
mrtg-user  /mrtg
/mrtg.cfg \
                                --logging
/var/log/mrtg.log

You can also run mrtg as a daemon process by
adding the line

RunAsDaemon:
Yes

to your mrtg configuration file and then
creating a startup script in your system startup sequence. Unfortunately, adding
startup scripts differs widely amongst different unix systems. The modern ones
normally have a directory called /etc/init.d or /etc/rc.d/init.d
where you put scripts which starts the process you want to run when the system
boots. Further you must create a symbolic link in /etc/rc3.d or
/etc/rc.d/rc?.d called S65mrtg (this is just a sample name ... it
is just important that it starts with S followed by a two digit number). If you
are not sure about this, make sure you consult the documentation of your system
to make sure you get this right.
A minimal script to put into
init.d might look like this:

#! /bin/sh
cd /usr/local/mrtg-2.14.6/bin && ./mrtg
--user=mrtg-user \
      
/home/httpd/mrtg/mrtg.cfg  
--logging /var/log/mrtg.log

Note that this will only work with
RunAsDaemon: Yes in your mrtg.cfg
file.

Author

Tobias Oetiker
tobi@oetiker.ch
>
Last Update: 09/06/06 by
Tobias Oetiker

               
               
               

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