How to install NRPE plugin on Ubuntu
In this article we will learn that how to install NRPE plugin in nagios. NRPE (Nagios Remote Plugin Executor) is used for executing Nagios plugins on remote client systems.
We have simple steps to install NRPE plugin in ubuntu. please let us know if you have any doubt and query by comments and mail.
Make sure that you have the following packages installed.
sudo apt-get update
sudo apt-get install -y autoconf gcc libc6 libmcrypt-dev make libssl-dev wget
Downloading the Source
cd /tmp
wget --no-check-certificate -O nrpe.tar.gz https://github.com/NagiosEnterprises/nrpe/archive/nrpe-3.2.1.tar.gz
tar xzf nrpe.tar.gz
Compile
Note that if you want to pass arguments through NRPE you must specify this in the configuration option as indicated below. If you prefer to you can omit the --enable-command-args flag. Removing this flag will require that all arguments be explicitly set in the nrpe.cfg file on each server monitored.
===== i386 =====
cd /tmp/nrpe-nrpe-3.2.1/
sudo ./configure --enable-command-args --with-ssl-lib=/usr/lib/i386-linux-gnu/
sudo make all
===== x86_x64 =====
cd /tmp/nrpe-nrpe-3.2.1/
sudo ./configure --enable-command-args --with-ssl-lib=/usr/lib/x86_64-linux-gnu/
sudo make all
Create User And Group:- This creates the nagios user and group.
sudo make install-groups-users
Install Binaries:-
This step installs the binary files, the NRPE daemon and the check_nrpe plugin.
If you only wanted to install the daemon, run the command make install-daemon instead of the command below. However it is useful having the check_nrpe plugin installed for testing purposes.
If you only wanted to install the check_nrpe plugin, refer to the section at the bottom of this KB article as there a lot of steps that can be skipped. Installing only the plugin is usually done on your Nagios server and workers.
sudo make install
Install Configuration Files, This installs the config files.
sudo make install-config
Update Services File
The /etc/services file is used by applications to translate human readable service names into port numbers when connecting to a machine across a network.
sudo sh -c "echo >> /etc/services"
sudo sh -c "sudo echo '# Nagios services' >> /etc/services"
sudo sh -c "sudo echo 'nrpe 5666/tcp' >> /etc/services"
Install Service / Daemon
This installs the service or daemon files.
===== 13.x / 14.x =====
sudo make install-init
===== 15.x / 16.x / 17.x =====
sudo make install-init
sudo systemctl enable nrpe.service
Information on starting and stopping services will be explained further on.
Configure Firewall
Port 5666 is used by NRPE and needs to be opened on the local firewall.
sudo mkdir -p /etc/ufw/applications.d
sudo sh -c "echo '[NRPE]' > /etc/ufw/applications.d/nagios"
sudo sh -c "echo 'title=Nagios Remote Plugin Executor' >> /etc/ufw/applications.d/nagios"
sudo sh -c "echo 'description=Allows remote execution of Nagios plugins' >> /etc/ufw/applications.d/nagios"
sudo sh -c "echo 'ports=5666/tcp' >> /etc/ufw/applications.d/nagios"
sudo ufw allow NRPE
sudo ufw allow 5666
sudo ufw reload
Update Configuration File
The file nrpe.cfg is where the following settings will be defined. It is located:
/usr/local/nagios/etc/nrpe.cfg
allowed_hosts=
At this point NRPE will only listen to requests from itself (127.0.0.1). If you wanted your nagios server to be able to connect, add it's IP address after a comma (in this example it's 192.168.0.142):
allowed_hosts=127.0.0.1,192.168.0.142
dont_blame_nrpe=
This option determines whether or not the NRPE daemon will allow clients to specify arguments to commands that are executed. We are going to allow this, as it enables more advanced NPRE configurations.
dont_blame_nrpe=1
The following commands make the configuration changes described above.
sudo sh -c "sed -i '/^allowed_hosts=/s/$/,192.168.0.142/' /usr/local/nagios/etc/nrpe.cfg"
sudo sh -c "sed -i 's/^dont_blame_nrpe=.*/dont_blame_nrpe=1/g' /usr/local/nagios/etc/nrpe.cfg"
Start Service / Daemon:- Different Linux distributions have different methods of starting NRPE.
===== 13.x / 14.x =====
sudo start nrpe
===== 15.x / 16.x / 17.x =====
sudo systemctl start nrpe.service
Test NRPE
Now check that NRPE is listening and responding to requests.
/usr/local/nagios/libexec/check_nrpe -H 127.0.0.1
You should see the output similar to the following:
NRPE v3.2.1
If you get the NRPE version number (as shown above), NRPE is installed and configured correctly.
You can also test from your Nagios host by executing the same command above, but instead of 127.0.0.1 you will need to replace that with the IP Address / DNS name of the machine with NRPE running.
Service / Daemon Commands
Different Linux distributions have different methods of starting / stopping / restarting / status NRPE.
===== 13.x / 14.x =====
sudo start nrpe
sudo stop nrpe
sudo restart nrpe
sudo status nrpe
===== 15.x / 16.x / 17.x =====
sudo systemctl start nrpe.service
sudo systemctl stop nrpe.service
sudo systemctl restart nrpe.service
sudo systemctl status nrpe.service
Installing The Nagios Plugins
NRPE needs plugins to operate properly. The following steps will walk you through installing Nagios Plugins.
These steps install nagios-plugins 2.2.1. Newer versions will become available in the future and you can use those in the following installation steps. Please see the releases page on GitHub for all available versions.
Please note that the following steps install most of the plugins that come in the Nagios Plugins package. However there are some plugins that require other libraries which are not included in those instructions. Please refer to the following KB article for detailed installation instructions:
Documentation - Installing Nagios Plugins From Source
Prerequisites :- Make sure that you have the following packages installed.
sudo apt-get install -y autoconf gcc libc6 libmcrypt-dev make libssl-dev wget bc gawk dc build-essential snmp libnet-snmp-perl gettext
Downloading the Source
cd /tmp
wget --no-check-certificate -O nagios-plugins.tar.gz https://github.com/nagios-plugins/nagios-plugins/archive/release-2.2.1.tar.gz
tar zxf nagios-plugins.tar.gz
To Compile and Install nagios plugin
cd /tmp/nagios-plugins-release-2.2.1/
sudo ./tools/setup
sudo ./configure
sudo make
sudo make install
Test NRPE + Plugins
Now you can check that NRPE is executing plugins correctly. The default configuration file /usr/local/nagios/etc/nrpe.cfg has the following command defined in it:
command[check_load]=/usr/local/nagios/libexec/check_load -w 15,10,5 -c 30,25,20
Using the check_load command to test NRPE:
/usr/local/nagios/libexec/check_nrpe -H 127.0.0.1 -c check_load
You should see the output similar to the following:
OK - load average: 0.01, 0.13, 0.12|load1=0.010;15.000;30.000;0; load5=0.130;10.000;25.000;0; load15=0.120;5.000;20.000;0;
You can also test from your Nagios host by executing the same command above, but instead of 127.0.0.1 you will need to replace that with the IP Address / DNS name of the machine with NRPE running.
