Monitoring MySQL server using nagios:

Step-: Download, Extract and install the MySQL Plugin:
wget http://labs.consol.de/wp-content/uploads/2010/10/check_mysql_health-2.1.3.tar.gz
tar -zxvf check_mysql_health-2.1.3.tar.gz
cd check_mysql_health-2.1.3
./configure --prefix=/usr/local/nagios --with-nagios-user=nagios --with-nagios-group=nagios --with-perl=/usr/bin/perl
make
make install
Step-: Create database user:
grant all privileges on *.* to 'nagios'@'localhost' identified by 'nagios';
Step-: Provide email address for nagiosadmin:
[Change contacts.cfg file accordingly.]
vi /usr/local/nagios/etc/objects/contacts.cfg

define contact{
contact_name nagiosadmin ; Short name of user
use generic-contact ; Inherit default values from generic-contact template (defined above)
alias Kedar ; Full name of user
email kedar@nitty-witty.com ; <<***** CHANGE THIS TO YOUR EMAIL ADDRESS ******
}
Step-: Configuring Nagios to Monitor MySQL Server
vi /usr/local/nagios/etc/nagios.cfg
add following line:
cfg_file=/usr/local/nagios/etc/objects/mysqlmonitoring.cfg
Define check_mysql_health command as follows:
vi /usr/local/nagios/etc/objects/commands.cfg
define command{
command_name check_mysql_health
command_line $USER1$/check_mysql_health -H $ARG4$ --username $ARG1$ --password $ARG2$ --port $ARG5$ --mode $ARG3$
}
Enter services to be monitored in mysqlmonitoring.cfg:
vi /usr/local/nagios/etc/objects/mysqlmonitoring.cfg
Add:
define service{
use local-service
host_name localhost
service_description MySQL connection-time
check_command check_mysql_health!nagios!nagios!connection-time!127.0.0.1!3306!
}

define service{
use local-service
host_name localhost
service_description MySQL slave-io-running
check_command check_mysql_health!nagios!nagios!slave-io-running!127.0.0.1!3306!
}

define service{
use local-service
host_name localhost
service_description MySQL slave-sql-running
check_command check_mysql_health!nagios!nagios!slave-sql-running!127.0.0.1!3306!
}
Here we’ve monitored 3 services: Connection-time, io thread and sql thread (replication) status. You can monitor more parameters described here: http://labs.consol.de/nagios/check_mysql_health/
Note: Every time you change configuration file, verify before starting nagios using command:
/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
Finally start nagios service and you’re done with nagios installation and configuration for monitoring MySQL.