setup nagios remote plugin executor

config remote hosts

install nrpe service

on debian

 $ sudo apt-get install nagios-nrpe-server

centos fedora rhel
```
 $ yum install nagios-nrpe
```

conf nrpe

config file location

 $ sudo pico /etc/nagios/nrpe.cfg
 ...
 server_port=5666
 ...

initiating nrpe service
1. for redhat based system the nrpe service needs to be added as a startup service
2. on debian ubuntu or linux mint
```
 $ sudo service nagios-nrpe-server restart
```
3. on centos fedora or rhel
```
 $ sudo service nrpe restart
 $ chkconfig nrpe on
```

verifying nrpe service status

     $ tail /var/log/syslog

     $ netstat -tpln | grep 5666

config nagios core server

install nrpe plugin

install package

 $ sudo apt-get install nagios-nrpe-plugin

 # redhat based system centos fedora rhel
 $ yum install nagios-plugins-nrpe

edit check_nrpe command

 $ sudo pico /etc/nagios-plugins/config/check_nrpe.cfg
 define command{
     command_name check_nrpe
     command_line /usr/lib/nagios/plugins/check_nrpe -H '$HOSTADDRESS$' -c '$ARG1$'
 }

defining nagios command for nrpe plugin

     $ sudo pico /usr/local/nagios/etc/object/commands.cfg
     define command{
         command_name check_nrpe
         command_line /usr/lib/nagios/plugins/check_nrpe -H '$HOSTADDRESS$' -c '$ARG1$'
     }

adding host and command definition

define remote hosts and commands to execut remotely on them

 # debian ubuntu or linux mint
 $ sudo pico /usr/local/nagios/etc/servers/node2.cfg
 ...
 define service {
     use                    generic-service
     host_name              node2
     service_description    Current Load
     check_command          check_nrpe!check_load
     check_interval         1
 }
 ...

restarting nagios service

verify config file

 # on debian ubuntu or linux mint
 $ /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

 # on centos fedora or rhel
 $ nagios -v /etc/nagios/nagios.cfg

restart
```
 $ sudo service nagios restart
```

config custom commands with nrpe

setup on remote servers

define commands

 $ sudo pico /etc/nagios/nrpe.cfg
 ...
 ## Warn if number of instances for process_abc exceeds 10. Critical for 20 ##
 command[check_process_abc]=/usr/lib/nagios/plugins/check_procs -w 1:10 -c 1:20 -C process_abc

 ## Critical if the number of instances for process_xyz drops below 1 ##
 command[check_process_xyz]=/usr/lib/nagios/plugins/check_procs -w 1: -c 1: -C process_xyz
 ...

setup on nagios core server

to apply the custom commands defined above

 # modify the service definition at nagios core server
 # /etc/local/nagios/etc/objects/nrpe.cfg
 # /etc/nagios/nrpe.cfg
 define service {
     use                    generic-service
     host_name              node2
     service_description    check process abc
     check_command          check_nrpe!check_process_abc
     check_interval         1
 }

 define service {
     use                    generic-service
     host_name              node2
     service_description    check process xyz
     check_command          check_nrpe!check_process_xyz
     check_interval         1
 }

fixed

CHECK_NRPE: Error - could not complete SSL handshake
1. this error is usually a client side problem
2. nagios client holds nrpe.cfg usually at /etc/nagios/nrpe.cfg
3. to fix this problem you need to edit this file
```
 $ sudo pico /etc/nagios/nrpe.cfg
 ...
 allowed_host=127.0.0.1,192.168.120.155
```
4. restart nrpe service
```
 $ sudo /etc/init.d/nagios-nrpe-server restart
```
5. test this from nagios server
```
 $ sudo /usr/lib/nagios/plugins/check_nrpe -H 192.168.120.152
 NRPE v2.15
```

setup nagios remote plugin executor

config remote hosts

config nagios core server

config custom commands with nrpe

fixed

references