Ttaportal.org Wp Content Uploads 2012-10-15 MRTG Installation Configuration Manual Version 3.0

MRTG Installation and configuration manual Version 3.0 2 Sept, 2011

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MRTG Installation and

Configuration Manual

SOMALI RESEARCH

AND

EDUCATION NETWORK

Team Member EmailKTH Credits

Zhaoyu Wang [email protected] 30

Saber Khamooshi [email protected] 15

Dan Wu [email protected] 15

Hantao Wang [email protected] 15

Ilias Karonis [email protected] 15

Muhammad Sheharyar Saeed [email protected] 15

Noman Mumtaz Ali [email protected] 15

Champion Bjrn Pehrson

Coach Bruce Zamaere

Anand Kannan

Erik Eliasson

My Anderberg

Hans Eriksson


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Content

Revision History ...................................................................................... 2

1. Introduction ......................................................................................... 3

2. Purpose ................................................................................................ 3

3. Scope ................................................................................................... 3

4. Audience .............................................................................................. 3

5. Pre-requisites ....................................................................................... 4

6. Installation ........................................................................................... 5

7. Configuration ....................................................................................... 6

8. Links &References ............................................................................ 10

Appendix A: Linux OIDs list ................................................................. 11


2

Revision History

Version Date Changes Author(s)

Version 1.0 29 July, 2011 Draft version of MRTG

installation and configuration

guide

Ilias Karonis

Version 2.0 19 August,2011 Skipped SNMP Installation &

Configuration as it is now

covered in a separate manual.

Added examples and

screenshots.

Added section explaining the

protocol mechanism more

thoroughly (SNMP MRTG

relationship, MIBs, OIDs).

Added appendix for Linux

OIDs

Ilias Karonis

Version 3.0 2 September,2011 Added explanatory material.

Updated screenshots.

Corrected grammatical

mistakes

Ilias Karonis,

Hantao Wang


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1. Introduction

MRTG is a highly configurable open source tool written in Perl which exploits the

SNMP capabilities of network devices for monitoring purposes. The role of MRTG is

vital for the supervision of our network, as it is destined to monitor and represent

graphically all inward and outward traffic on the links of the networks

router/gateway together with other important parameters such as CPU, memory and

disk usage.

2. Purpose

The purpose of the present document is to guide through the installation and

configuration of MRTG (Multi Router Traffic Grapher) on the Ubuntu server which

will operate in the SomaliRen Network Operations Center.

3. Scope

The document provides a step by step guidance on how to install as well as configure

MRTG on the NOCs Ubuntu Server in order to satisfy the required monitoring

specifications.

4. Audience

This manual is addressed to the SomaliRen teams members working on network

deployment tasks and the responsible for the NOC Somali network engineers.


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5. Pre-requisites

To successfully install and run MRTG, the following are explicitly required:

C and Perl compilers - As the program comes in C and Perl source code,

corresponding compilers are needed. Most often compilers such as GCC and

Perl are incorporated in the Ubuntu OS.

gd A graph drawing library

libpng Required by gd in order to produce gif graphs

zlib Needed by libpng for graphic files compression

net-snmpor similar SNMP package A monitoring protocol package which

implements SNMP. As mentioned earlier, MRTG operates based on SNMP

information. The managed devices -Bifrost routers in our case- must be able to

act as SNMP agents to be remotely monitored by MRTG.

The installation of the aforementioned packages and libraries is analytically covered

in the MRTG websites Unix-guide page [1].

This manual requires basic knowledge on the SNMP protocol theory and

configuration as MRTG operation is based on it. It is highly recommended that the

reader goes through the SNMP Installation & Configuration Manual [2]

first.


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6. Installation

The MRTG package can be retrieved and installed from the repository using the

command

# sudo apt-get install mrtg

The installation procedure will prompt the user with a message about the

/etc/mrtg.cfg configuration files accessibility. The default option Yes will set

permission at 640, which means that the indicated user has read and write permissions

while the rest of the group has only read permissions. The No option will set

permissions at 644, which differs from 640 in the fact that provides read permissions

to all, even outside of the group. It is therefore recommended for security reasons to

select Yes.

It is a good idea to keep things orderly moving the main configuration file from /etc to

its own separate directory issuing the command:

#sudo mkdir /etc/mrtg &&sudo mv /etc/mrtg.cfg /etc/mrtg


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7. Configuration

The next step is to properly configure MRTG to monitor our networking devices, in

our case the router/gateway. MRTG is mainly handled by the mrtg.cfg configuration

file, which is stored in the /etc directory. The configuration parameters can either be

input directly in the mrtg.cfg or by making use of the cfgmaker [3] which is provided

with the MRTG installation.

First we issue the cfgmaker to communicate with the targetSNMPagent using the

appropriate community name in order to gather information and form the

configuration file mrtg.conf. The general command form is

#sudocfgmaker --output /etc/mrtg/mrtg.cfg

community.name@routers-IP-address

Following the example used in the SNMP Installation & Configuration manual [2]

, we

use the community name somren for monitoring two routers with IP addresses

192.16.126.100 and 192.16.126.200at the same command:

#sudo cfgmaker --output /etc/mrtg/mrtg.cfg

[email protected]@192.16.126.200

Recall that these two Bifrost routers have been configured to respond on SNMP

requests originatedspecifically by our monitoring device. After establishing a SNMP

connection with the specified router(s), the cfgmaker will use the received SNMP

information to generate an initial mrtg.conf configuration file which we are going to

refine shortly. It is suggested from now on to manually input the lines into the

configuration file so there is a full view of the configuration.

Here we present the basic configuration elements to be included in the mrtg.cfg for

the establishment of the monitoring.

#Global Settings

RunAsDaemon: yes

Interval: 5

EnableIPv6: no

WorkDir: /var/www/mrtg

Options[_]: bits, growright


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Logdir: /var/log

WriteExpires: yes

The RunAsDaemon option is used to daemonize MRTG so there is no need to restart it

or configure cron to do so. The Interval is the period used to call MRTG. The

default and minimum value is 5 minutes .WorkDirand Logdir specify the webpage

and log file directories respectively. The WriteExpires switch instructs MRTG to

include expiration tags at the produced meta files for CERN and Apache servers.

One should be always careful when inspecting the configuration file, as some

important lines could be commented. If the link to be monitored is idle for

example, its interface is going to be commented. Go carefully through the

mrtg lines and especially in those beginning with Targetas they are the ones

who define the monitored objects. Be sure which interfaces should be

monitored and which not.

Note that the generated code here is HTML. That means its easy to manipulate the

generated page by changing the code in the mrtg.conf file.

MRTG provides the capability of monitoring more than just the traffic on an interface;

it can monitor disk usage, free memory, CPU usage and many more. As mentioned

plenty of times before, MRTG uses information provided by the SNMP protocol. This

information resides in the SNMP agents Management Information Base (MIB).


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Each managed object in the MIB hierarchical base is uniquely identified by an Object

Identifier (OID).

We can use an OID value to query the SNMP agent on that objects information. Lets

say for example we want to retrieve the value of the one minute CPU load on a

Bifrost router with IP 192.16.126.100. We use the snmpwalk command

#snmpwalk v 2c c somren 192.16.126.100 .1.3.6.1.4.1.2021.10.1.3.1

and we will see the value returned from the SNMP agent of the router. This is

basically how MRTG works. It queries the SNMP agent to retrieve information held

inside the MIB.

After having been acquainted with the OIDs, we can expand the mrtg.conf with our

own targeted objects by simply adding a new Target.

The next lines produce a monitoring page for the Free and Total Memory of the

192.16.126.100 Bifrost:

Target[Free_vs_Total_RAM]: .1.3.6.1.4.1.2021.4.3.0&.1.3.6.1.4.

1.2021.4.5.0:[email protected]

MaxBytes[Free_vs_Total_RAM]: 8000000000

Title[Free_vs_Total_RAM]: Router Free Memory

PageTop[Free_vs_Total_RAM]: Router Free Memory

Unscaled[Free_vs_Total_RAM]: ymwd

YLegend[Free_vs_Total_RAM]: Free RAM

ShortLegend[Free_vs_Total_RAM]: kB

LegendI[Free_vs_Total_RAM]: Free

LegendO[Free_vs_Total_RAM]: Total

For a list of the Linux Object Identifiers, refer to Appendix A.

Having completed the MRTG configuration, we restart MRTG to activate the changes

made

# sudo env LANG=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg

and give the following indexmaker [4]

command necessary to create the web pages:

# sudo indexmaker --ouput=/var/www/mrtg/index.html /etc/mrtg/mrtg.cfg


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By issuing the above command we use default parameters. However, indexmaker can

polish and shape the information display in interesting ways, performing data filtering

or changing the appearance of the pages for example. For more information, please

refer to the indexmaker online guide [4]

.

Below are how the MRTG graphs look like in our test network:

This concludes the set of steps needed to bring MRTG up on a basic operational level.

The generated webpage can now be accessed at http://server-address/mrtg.

It is possible for the first few times to receive error messages regarding

missing log files. This is natural of course as MRTG operation has just started

and the messages should be ignored.


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8. Links &References

[1] OETIKER & PARTNER AG, MRTG Unix installation guide [Online], Available:

http://oss.oetiker.ch/mrtg/doc/mrtg-unix-guide.en.html

Last accessed August 2011

[2] SomaliREN Team, SNMP Installation & Configuration Manual [Online],

Available:

http://vm-199.xen.ssvl.kth.se/csdlive/sites/default/files/projects/SNMP Installation &

Configuration Manual Version 2.pdf


[3] OETIKER & PARTNER AG, MRTG cfgmaker guide [Online],

Available:http://oss.oetiker.ch/mrtg/doc/cfgmaker.en.html


[4] OETIKER & PARTNER AG, MRTG indexmaker guide [Online],

Available:http://oss.oetiker.ch/mrtg/doc/indexmaker.en.html



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Appendix A: Linux OIDs list

CPU Statistics Load:

1 minute Load: .1.3.6.1.4.1.2021.10.1.3.1

5 minute Load: .1.3.6.1.4.1.2021.10.1.3.2

15 minute Load: .1.3.6.1.4.1.2021.10.1.3.3

CPU:

percentage of user CPU time: .1.3.6.1.4.1.2021.11.9.0

raw user cpu time: .1.3.6.1.4.1.2021.11.50.0

percentages of system CPU time: .1.3.6.1.4.1.2021.11.10.0

raw system cpu time: .1.3.6.1.4.1.2021.11.52.0

percentages of idle CPU time: .1.3.6.1.4.1.2021.11.11.0

raw idle cpu time: .1.3.6.1.4.1.2021.11.53.0

raw nice cpu time: .1.3.6.1.4.1.2021.11.51.0

Memory Statistics:

Total Swap Size: .1.3.6.1.4.1.2021.4.3.0

Available Swap Space: .1.3.6.1.4.1.2021.4.4.0

Total RAM in machine: .1.3.6.1.4.1.2021.4.5.0

Total RAM used: .1.3.6.1.4.1.2021.4.6.0

Total RAM Free: .1.3.6.1.4.1.2021.4.11.0

Total RAM Shared: .1.3.6.1.4.1.2021.4.13.0

Total RAM Buffered: .1.3.6.1.4.1.2021.4.14.0

Total Cached Memory: .1.3.6.1.4.1.2021.4.15.0

Disk Statistics

Path where the disk is mounted: .1.3.6.1.4.1.2021.9.1.2.1

Path of the device for the partition: .1.3.6.1.4.1.2021.9.1.3.1

Total size of the disk/partion (kBytes): .1.3.6.1.4.1.2021.9.1.6.1

Available space on the disk: .1.3.6.1.4.1.2021.9.1.7.1

Used space on the disk: .1.3.6.1.4.1.2021.9.1.8.1

Percentage of space used on disk: .1.3.6.1.4.1.2021.9.1.9.1


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Percentage of inodes used on disk: .1.3.6.1.4.1.2021.9.1.10.1

System Uptime: .1.3.6.1.2.1.1.3.0

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