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MRTG is Multi Router Traffic Grapher (MRTG) is a tool to monitor the traffic load on network links. MRTG generates HTML pages containing PNG images which provide a LIVE visual representation of this traffic.

MRTG Requirements

Apache webserver with perl support
NET-SNMP
GD
Libpng
zlib

If you want to download MRTG you can download from here

Preparing you System for MRTG Instalaltion

First you need to install the required compilers

#apt-get install gcc make g++

Apache 2 Installation with perl support

Follow these instructions to install apache2 with perl support

MRTG Installation

Now we need to install mrtg and snmp

Installing MRTG in Debian, Ubuntu and Kubuntu

#apt-get install mrtg snmpd

The installation will create an mrtg subdirectory where the Apache Web pages reside. On your Debian,ubnutu,kubuntu systems the path of this subdirectory is:

/var/www/mrtg

Now you need to edit the mrtg configuration file to edit the some of the settings

File is located at /etc/mrtg.cfg you need to change the global settings as follows

# Global Settings

RunAsDaemon: yes
EnableIPv6: no
WorkDir: /var/www/mrtg
Options[_]: bits,growright
WriteExpires: Yes

Title[^]: Traffic Analysis for

You will find a crontab running every 5 minutes as user root

# cat /etc/cron.d/mrtg
0-55/5 * * * * root if [ -x /usr/bin/mrtg ] && [ -r /etc/mrtg.cfg ]; then env LANG=C /usr/bin/mrtg /etc/mrtg.cfg >> /var/log/mrtg/mrtg.log 2>&1; fi

Now we need to assign the snmp community name in snmp configration file /etc/snmp/snmpd.conf

# sec.name source community
# com2sec paranoid default public
com2sec readonly default public
#com2sec readwrite default private

Now you need to restart the snmp service

#/etc/init.d/snmpd restart

The configuration file creating using

#cfgmaker public@localhost > /etc/mrtg.cfg

Creating a configuration file for a device using cfgmaker

#cfgmaker public@192.168.0.1 >> /etc/mrtg.cfg

With the configuration file created correctly there’s only one other thing you have to do and that’s to use the indexmaker utility to create the summary home page. Since you have to re-run this command every time you make certain changes to the /etc/mrtg.cfg configuration file.

Creating index file for the webserver using indexmaker

#indexmaker /etc/mrtg.cfg > /var/www/mrtg/index.html

Now you need to reboot your system wait for five minutes or so and then take a look at your summary home page. If your Debian,ubuntu,kubuntu system’s IP address is 192.168.0.1 then you’d type in the following in the address bar of a browser running on a system on the same network:

http://192.168.0.1/mrtg/

Your summary home page should come up with a graph for each target entry in the configuration file. If a graph looks like there’s no data on it, click on it and check the statistics to see if any traffic is being seen. Small amounts of traffic won’t show up on the graphs because we used the Unscaled statement

Some of examples how to monitor cpu , memory , Disk usage

CPU Usage

/etc/mrtg/cpu.cfg

WorkDir: /var/www/mrtg
LoadMIBs: /usr/share/snmp/mibs/UCD-SNMP-MIB.txt
Target[localhost.cpu]:ssCpuRawUser.0&ssCpuRawUser.0:public@127.0.0.1+ ssCpuRawSystem.0&ssCpuRawSystem.0:public@127.0.0.1+
ssCpuRawNice.0&ssCpuRawNice.0:public@127.0.0.1
RouterUptime[localhost.cpu]: public@127.0.0.1
MaxBytes[localhost.cpu]: 100
Title[localhost.cpu]: CPU Load
PageTop[localhost.cpu]: Active CPU Load %
Unscaled[localhost.cpu]: ymwd
ShortLegend[localhost.cpu]: %
YLegend[localhost.cpu]: CPU Utilization
Legend1[localhost.cpu]: Active CPU in % (Load)
Legend2[localhost.cpu]:
Legend3[localhost.cpu]:
Legend4[localhost.cpu]:
LegendI[localhost.cpu]: Active
LegendO[localhost.cpu]:
Options[localhost.cpu]: growright,nopercent

Memory Usage

/etc/mrtg/mem.cfg

LoadMIBs: /usr/share/snmp/mibs/HOST-RESOURCES-MIB.txt
Target[localhost.mem]: .1.3.6.1.4.1.2021.4.6.0&.1.3.6.1.4.1.2021.4.6.0:public@localhost
PageTop[localhost.mem]:Free Memory
WorkDir: /var/www/mrtg
Options[localhost.mem]: nopercent,growright,gauge,noinfo
Title[localhost.mem]: Free Memory
MaxBytes[localhost.mem]: 1000000
kMG[localhost.mem]: k,M,G,T,P,X
YLegend[localhost.mem]: bytes
ShortLegend[localhost.mem]: bytes
LegendI[localhost.mem]: Free Memory:
LegendO[localhost.mem]:
Legend1[localhost.mem]: Free memory, not including swap, in bytes

Memory Monitoring (Total Versus Available Memory)

/etc/mrtg/memfree.cfg

LoadMIBs: /usr/share/snmp/mibs/HOST-RESOURCES-MIB.txt
Target[server.memory]: memAvailReal.0&memTotalReal.0:public@localhost
Title[server.memory]: Free Memory
PageTop[server.memory]: < H1 >Free Memory< /H1 >
MaxBytes[server.memory]: 100000000000
ShortLegend[server.memory]: B
YLegend[server.memory]: Bytes
LegendI[server.memory]: Free
LegendO[server.memory]: Total
Legend1[server.memory]: Free memory, not including swap, in bytes
Legend2[server.memory]: Total memory
Options[server.memory]: gauge,growright,nopercent
kMG[server.memory]: k,M,G,T,P,X

Memory Monitoring (Percentage usage)

/etc/mrtg/mempercent.cfg

LoadMIBs: /usr/share/snmp/mibs/HOST-RESOURCES-MIB.txt
Title[server.mempercent]: Percentage Free Memory
PageTop[server.mempercent]: < H1 >Percentage Free Memory< /H1 >
Target[server.mempercent]: ( memAvailReal.0&memAvailReal.0:publicy@localhost ) * 100 / ( memTotalReal.0&memTotalReal.0:public@localhost )
options[server.mempercent]: growright,gauge,transparent,nopercent
Unscaled[server.mempercent]: ymwd
MaxBytes[server.mempercent]: 100
YLegend[server.mempercent]: Memory %
ShortLegend[server.mempercent]: Percent
LegendI[server.mempercent]: Free
LegendO[server.mempercent]: Free
Legend1[server.mempercent]: Percentage Free Memory
Legend2[server.mempercent]: Percentage Free Memory

Disk Usage

/etc/mrtg/disk.cfg

LoadMIBs: /usr/share/snmp/mibs/HOST-RESOURCES-MIB.txt
Target[server.disk]: dskPercent.1&dskPercent.2:public@localhost
Title[server.disk]: Disk Partition Usage
PageTop[server.disk]: < H1 >Disk Partition Usage /home and /var< /H1 >
MaxBytes[server.disk]: 100
ShortLegend[server.disk]: %
YLegend[server.disk]: Utilization
LegendI[server.disk]: /home
LegendO[server.disk]: /var
Options[server.disk]: gauge,growright,nopercent
Unscaled[server.disk]: ymwd

Creating jobs for CPU , Memory and Disk Usage

CPU

/etc/cron.mrtg/cpu

#!/bin/sh
/usr/bin/mrtg /etc/mrtg/cpu.cfg

Memory

/etc/cron.mrtg/mem

#!/bin/sh
/usr/bin/mrtg /etc/mrtg/mem.cfg

Memory Free

/etc/cron.mrtg/memfree

#!/bin/sh
/usr/bin/mrtg /etc/mrtg/memfree.cfg

Memory Percentage

/etc/cron.mrtg/mempercent

#!/bin/sh
/usr/bin/mrtg /etc/mrtg/mempercent.cfg

Disk

/etc/cron.mrtg/disk

#!/bin/sh
/usr/bin/mrtg /etc/mrtg/disk.cfg

Run each script 3 times (disregard the warnings)

/etc/cron.mrtg/cpu
/etc/cron.mrtg/mem
/etc/cron.mrtg/memfree
/etc/cron.mrtg/mempercent
/etc/cron.mrtg/disk

Make the Index Files

#/usr/bin/indexmaker –output=/var/www/mrtg/index.html \
–title=”Memory and CPU Usage ” \
–sort=name \
–enumerate \
/etc/mrtg/cpu.cfg \
/etc/mrtg/mem.cfg \
/etc/cron.mrtg/memfree \
/etc/cron.mrtg/mempercent \
/etc/cron.mrtg/disk

Make the mrtg.cfg file

#cfgmaker –global “WorkDir: /var/www/mrtg/” \
–global “Options[_]: growright,bits” \
–ifref=ip \
public@localhost > /etc/mrtg/mrtg.conf

Cronjob setup

/bin/cat >> /var/spool/cron/crontabs/root
*/5 * * * * /bin/run-parts /etc/cron.mrtg 1> /dev/null

Now you logon to your web browser http://192.168.0.1/mrtg/ and Now you should see CPU,Memory and Disk Usage graphs.

If you want more documentation about MRTG check here