How to Install the NRPE daemon

How to Install the NRPE daemon

Step-1:

Download the source code tarball of the NRPE addon (visit https://www.nagios.org/downloads/nagios-coreaddons/ for links to the latest versions). At the time of writing, the latest version of NRPE was 3.2.1.

  cd ~/downloads
  wget https://github.com/NagiosEnterprises/nrpe/releases/download/nrpe3.2.1/nrpe-3.2.1.tar.gz

Extract the NRPE source code tarball:

tar xzf nrpe-3.2.1.tar.gz

Step-2:

  cd nrpe-nrpe-3.2.1

Compile the NRPE addon:

  ./configure
  make all

If you didn't create the groups and users in (i) above, do it now:

  make install-groups-users

Install the NRPE plugin (for testing), daemon, and sample daemon configuration file.

  make install
  make install-config

Step-3:

If you want NRPE to run per-connection under inetd, xinetd, launchd, systemd, smf, etc. run the following

command:

  make install-inetd

Step-4:

Make sure nrpe 5666/tcp is in your /etc/services file, if applicable.

If you want to run NRPE all the time under init, launchd, systemd, smf, etc. run the followning command:

  make install-init

You may need to reload or restart the controlling daemon using one of the following (or similar) commands:

  service xinetd restart
  systemctl reload xinetd # systemd
  systemctl enable nrpe && systemctl start nrpe

Step-5:

Test the NRPE daemon locally

Its time to see if things are working properly. Make sure the nrpe daemon is running:

   netstat -at | egrep "nrpe|5666"

   tcp 0 0 *:nrpe *:* LISTEN

Step-6:

If the second line above shows up, great! If it doesn't, make sure of the following

  • You added the nrpe entry to your /etc/services file
  • The only_from directive in the /etc/xinetd.d/nrpe file contains an entry for "127.0.0.1"
  • xinetd is installed and started
  • The appropriate line in /etc/inetd.conf has been uncommented
  • Check the system log files for references about xinetd or nrpe and fix any problems that are reported

Next, check to make sure the NRPE daemon is functioning properly. To do this, run the check_nrpe plugin

that was installed for testing purposes. You should see the second line below:

  /usr/local/nagios/libexec/check_nrpe -H localhost
  NRPE v3.2.1

If everything worked, add the hostname or IP address of the nagios server to the /etc/xinetd.d/nrpe

file, or /etc/hosts-allow and hosts-deny.

Step-7:

Open firewall rules

If the server has a firewall running, you need to allow access to the NRPE port (5666) from the Nagios

server.

In Fedora and Red Hat Linux, you would use the following commands:

   iptables -I RH-Firewall-1-INPUT -p tcp -m tcp –dport 5666 -j ACCEPT
   service iptables save

On other systems and other firewalls, check the documentation or have an administrator open the port.

Customize the NRPE commands

The sample NRPE config file that got installed contains several command definitions that you'll likely use to

monitor this machine. The command definitions are used to (surprise) define commands that the NRPE

daemon will run to monitor local resources and services. The sample command definitions run some of the

plugins that were installed in step

2. You can edit the command definitions, add new commands, etc, by

editing the NRPE config file using your favorite editor:

   vi /usr/local/nagios/etc/nrpe.cfg

More information on customizing the commands can be found on page 16 in the section titled

"Customizing Your Configuration".

For the time being, I'll assume you're using the sample commands that are defined. You can test some of

these by running the following commands:

   /usr/local/nagios/libexec/check_nrpe -H localhost -c check_user

Step-8: