NRPE Installation

The NRPE addon is designed to allow you to execute Nagios plugins on remote Linux/Unix machines. This allow Nagios to monitor "local" resources (like CPU load, memory usage, etc.) on remote machines

Nagios NRPE Installation and Configuration

NRPE Installation

 

 Install nagios-nrpe & nagios-plugins using yum.
 Change the "allowed_hosts" value to the IP of nagios server in /etc/nagios/nrpe.cfg

yum install nagios-nrpe nagios-plugin-nrpe
chkconfig nrpe on
/sbin/chkconfig --list
ls /usr/lib/nagios/plugins
nano /etc/nagios/nrpe.cfg

allowed_hosts= local host  -- as the connection need to be established with the server itself

/etc/init.d/nrpe restart 

Port 5666 need to be opened for nagios

/sbin/iptables -I INPUT -p tcp -m tcp --dport 5666 -j ACCEPT

 

I am briefing the  NRPE  motoring with the help of an example.   Assume we are trying to implement a distributed monitoring.   

Master Server :-  Monitoring server          :   A
Remote server :- Server  to be monitored :   Z

Master server is having   Nagios ,  Nagios-nrpe,  nagios-plugin-nrpe, hostgroups,  servers 

Host Group:  A host group definition is used to group one or more hosts together for simplifying configuration   

define hostgroup {
	hostgroup_name	hostgroup_name
	alias	alias
	members	hosts
	hostgroup_members	hostgroups
	notes	note_string
	notes_url	url
	action_url	url

} 

Example of   "/etc/nagios/hostgroups/hostgroup.cfg"

define hostgroup  {
hostgroup_name    Google Linux
alias             Google
members           host1, host2 
} 

Servers:  The servers and the services that are being monitored using the Monitoring server A (main nagios server). 

example:   /etc/nagios/servers/"host1.cfg"

The "host1" file is used to specify which services need to be monitored in the  remote server "host1"

This file contains the definition of the services that need to be checked.

example: /etc/nagios/servers/google.cfg

define service{
        use                             local-service         
        host_name                       google.cfg

service_description             HTTP
        check_command                   check_http
        notifications_enabled           1
        }

check_command: This directive is used to specify the short name of the command that Nagios will run in order to check the status of the service.

The maximum amount of time that the service check command can also mentioned after check_command 

notifications_enabled:  This directive is used to determine whether or not notifications for this host are enabled. Values: 

0 = disable host notifications, 

1 = enable host notifications.

We have to define all the services that need to be checked/ monitored separately ie each  check_command will have separate  definition 

example of check command:  check_mysql -H $HOSTADDRESS$ -u $ARG1$ -p $ARG2$ -d $ARG3$

check_command   check-host-alive

check_mysql!powerdns_services!NmLY6DeM2Zvt2fUW!powerdns

check_mysql is defined in the remote host, ie the service need to monitored

 $ARG1$ is powerdns_services, 

$ARG2$ is NmLY6DeM2Zvt2fUW,

$ARG3$ is powerdns

You can refer the page for more definitions  http://nagioswiki.com/wiki/index.php/Checking_NT_Services_with_Nagios

Monitoring Load

nano /etc/nagios/nrpe.cfgcommand[check_load]=/usr/lib64/nagios/plugins/check_load -w 15,10,10 -c 30,25,20


/etc/init.d/nrpe restart