Install NRPE (to remote host, NOT on the controller)

Install NRPE (to remote host, NOT on the controller)

# Use nrpe on remote host instead of ncpa only if ncpa is not working 
# this setup require BOTH nrpe AND plugins

# Use this when on debian 7/8

################
#     NRPE     #
################

# Execute all as super user !

# Prereq for nrpe
apt install libssl-dev build-essential

# Installing nrpe
cd /tmp
wget -O nrpe-3.2.1.tar.gz https://github.com/NagiosEnterprises/nrpe/releases/download/nrpe-3.2.1/nrpe-3.2.1.tar.gz
tar xvf nrpe-*.tar.gz
rm -f nrpe-*.tar.gz
cd nrpe-*
./configure --enable-command-args --with-nagios-user=nagios --with-nagios-group=nagios --with-ssl=/usr/bin/openssl --with-ssl-lib=/usr/lib/x86_64-linux-gnu
make all
make install-groups-users
make install
make install-init
make install-config

# enable incoming traffic for check_nrpe
iptables -I INPUT -p tcp --destination-port 5666 -j ACCEPT

################  IF YOU WANT TO USE UFW ##############
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 reload
##########################################################

#               IMPORTANT
# Open with nano /usr/local/nagios/etc/nrpe.cfg
# and add your ip to list of allowed ips

# enable/run/check service
systemctl enable nrpe.service
systemctl start nrpe.service
systemctl status nrpe.service

# if not available systemctl, simply run 
# /etc/init.d/nrpe restart

# cleanout
cd /tmp
rm nrpe-3.2.1 -rf

################################################################
#                        Plugins                               #
# Will be installed into /usr/local/nagios/libexec             #
################################################################

# Nagios Plugin Prerequisites
apt-get install -y autoconf gcc libc6 libmcrypt-dev make libssl-dev wget bc gawk dc build-essential snmp libnet-snmp-perl gettext

# Nagios Plugin Download 
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
rm nagios-plugins.tar.gz

# Nagios Plugin Installation
cd nagios-plugins-release-2.2.1
./tools/setup
./configure
make
make install
cd /tmp
rm nagios-plugins-release-2.2.1 -rf

#########################
#   Starting services   #
#########################


# enable/run/check service
systemctl enable nrpe.service
systemctl start nrpe.service
systemctl status nrpe.service


#########################
#   Usefull commands    #
#########################

# Edit file: nano /usr/local/nagios/etc/nrpe.cfg
# Add custom commands like ...
command[check_root_partition]=/usr/local/nagios/libexec/check_disk -w 10% -c 5% -p / -u GB

# The content of the following script is avaiable as gist:
# search realtebo/chustom_check_mem script for nrpe
command[check_mem]=/usr/local/nagios/libexec/custom_check_mem -w 20% -c 10%

# then give it execution permissions
# sudo chmod a+x /usr/local/nagios/libexec/custom_check_mem


#############################
#   How to config the host  #
#############################

See `example config for a server without npa`