Install MRTG.
Configure and setup MRTG.
Add new definitions to Nagios. (Part 2)
Setup and restart Nagios to view new bandwidth defined services. (Part 2)
Part 1 -
Install MRTG on CentOS
We will cover in
this initial article the MRTG installation for CentOS 6.4, it works too in
CentOS 6.3 and other distro.
First install the
snmp tools needed.
# yum
install net-snmp net-snmp-utils rrdtool
Afterwards install
the MRTG
#yum
install mrtg
Now it's time to
decide where do you want to see your graphs and infos. Maybe in a MRTG dir
in wwwroot where you will find all the datas in the future.
mkdir
/var/www/html/mrtg
Now let's go an
create a good mrtg.conf file. It's important, so
take a while doing the correct settings.
Used command
cfgmaker to create log file relate with information of device
cfgmaker
--ifref=descr --ifdesc=descr --snmp-options=:::::2 --global 'WorkDir:
/var/www/html/mrtg/router_name/' --global 'Options[_]: bits' --output
/etc/mrtg/mrtg_router_name.cfg "snmp
commnunity"@x.x.x.x":::::2"
- Snmp-options=:::::2 used for data graphing over 100Mb/s
And then we need to
create index file for storing data information by using command below
#
indexmaker --output=/var/www/mrtg/index.html /etc/mrtg/mrtg_router_name.cfg
You can you command
to show graph manually after 5 minute
#
/usr/bin/mrtg /etc/mrtg/mrtg.cfg --lock-file /var/lock/mrtg/mrtg_l
--confcache-file /var/lib/mrtg/mrtg.ok
Then we need to
create crontab in order to to run command to generate data every 5 minutes by
# vim
/etc/cron.d/mrtg
*/5 * * *
* root LANG=C LC_ALL=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg --lock-file
/var/lock/mrtg/mrtg_l --confcache-file /var/lib/mrtg/mrtg.ok
Note: one command
just can execute for only one device, if you have many device you need to
create files more to execute to trap data from other devices.
#service
httpd restart
Then you can access
by http://x.x.x.x/mrtg
- Part 2 - Monitoring bandwidth with Nagios - Settings alerts.
Add
a service to Nagios to monitor port bandwidth
check_local_mrtgtraf uses the MRTG. So, first install MRTG
for this to work properly. The *.log file mentioned below should point to the
MRTG log file on your system, the MRTG work directory we have created.
The check_local_mrtgtraf is
included in Nagios plugins.
#vim /usr/local/nagios/object/router_name.cfg
And
add this parameter below:
define service{
use generic-service
host_name core-switch
service_description Port 1 Bandwidth Usage
check_command check_local_mrtgtraf!/var/www/mrtg/router_name_interface.log!AVG!1000000,2000000!5000000,5000000!10
}
use generic-service
host_name core-switch
service_description Port 1 Bandwidth Usage
check_command check_local_mrtgtraf!/var/www/mrtg/router_name_interface.log!AVG!1000000,2000000!5000000,5000000!10
}
The
"AVG" option tells it that it should use average bandwidth
statistics.
The
"1000000,2000000" options are the warning thresholds (in bytes) for
incoming traffic rates.
The
"5000000,5000000" are critical thresholds (in bytes) for outgoing
traffic rates.
The
"10" option causes the plugin to return a CRITICAL state if the MRTG
log file is older than 10 minutes (it should be updated every 5 minutes).
For
more check_local_mrtgtraf properties, run the plugin help.
Remember
to validate Nagios settings and restart if all settings are ok.
# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
# /etc/init.d/nagios restart
