Configuring server host to respond to nagios host (monitor remote services) – CentOS
Download nagios plugin and nagios-nrpe plugin in the server host (client that talks with nagios host) from nagios website. The files comes as .tar files and you need to configure them for their use. Move the files to /usr/src
$ cd /usr/src
$ tar zxvf nagios-plugins-1.4.13.tar.gz
$ cd nagios-plugins-1.4.13
$ ./configure –prefix=/usr/local/nagios
$ make install
Now nagios-plugin is successfully installed. Go back to /usr/src
$ cd ..
$ tar zxvf nrpe-2.12.tar.gz
$ cd nrpe-2.12
$ ./configure –enable-ssl
By default, you will get the following list of information. If you want to change these values you can go ahead and change them.
NRPE port: 5666
NRPE user: nagios
NRPE group: nagios
Nagios user: nagios
Nagios group: nagios
$ make all
If the nrpe client compiled without any error then you can continue with installation settings to make these two comptuers talk to each other.
$ make install-plugin
$ make install-daemon
$ make install-daemon-config
$ make install-xinetd
$ cp src/nrpe /usr/local/nagios/libexec/
$ cp src/check_nrpe /usr/local/nagios/libexec/
Now the executables are in place and we can configure the NRPE daemon on the remote system.
Search for the string “allowed_hosts” in /etc/nagios/nrpe.cfg and change it to the nagios host IP address (this restricts the server host to listen only from the above IP)
# Set this to listen only from nagios host
Restart nagio nrpe in ubuntu
* Identify where nrpe.cfg and make the necessary changes to that configuration file. Save it. Then restart the nrpe server by
$ /etc/init.d/nagios-nrpe-server restart
From centos, if you want to start xinetd
$ /etc/init.d/xinetd restart
From the server host execute telnet to see if you can communicate with nagios host
telnet remote-nagios-host 5666
If you get the following message then everything sounds fine until now
Escape character is ‘^]’.
FROM NAGIOS HOST
Add the following entries in developer-host.cfg (the name of the file is configurable from nagios.cfg file)
use linux-server ; Name of host template to use
Restart nagios from nagios host and you are ready to go.
Note: If you have custom commands that you need to run or configure certain perl files, then you can add the entry for the command in nagios.cfg and about the execution entry
in the custom defined .cfg file for that host. This custom defined entry needs to be configured in the nrpe.cfg file that is to be located in the server host (client listening to nagios host)
For configuring the nagios nrpe host, client on Ubuntu check the following resources