Installing Nagio NRPE on Ubuntu 18.04 through 22.04
A short tutorial on moving from Nagios NRPE using apt-get to source installation. We want to first remove all Nagios parts that were installed via apt:
sudo apt-get update apt list --installed | grep nagios nagios-nrpe-server/trusty,now 2.15-0ubuntu1 amd64 [installed] nagios-plugins/trusty,now 1.5-3ubuntu1 all [installed] nagios-plugins-basic/trusty,now 1.5-3ubuntu1 amd64 [installed,automatic] nagios-plugins-common/trusty,now 1.5-3ubuntu1 amd64 [installed,automatic] nagios-plugins-standard/trusty,now 1.5-3ubuntu1 amd64 [installed,automatic] apt-get remove nagios-nrpe-server nagios-plugins nagios-plugins-basic nagios-plugins-common nagios-plugins-standard
Ensure we still have the nagios user:
sudo useradd nagios
Next, install the basics which will let us build NRPE:
sudo apt-get install build-essential openssl libssl-dev unzip make
Now we can download and install Nagios plugins:
cd /opt curl -L -O http://nagios-plugins.org/download/nagios-plugins-2.3.3.tar.gz tar zxf nagios-plugins-*.tar.gz rm -f nagios-plugins-*.tar.gz cd nagios-plugins-* ./configure --with-nagios-user=nagios --with-nagios-group=nagios --with-openssl sudo make sudo make install
Next install NRPE on 18.04 and 20.04:
cd /opt curl -L -O https://github.com/NagiosEnterprises/nrpe/releases/download/nrpe-3.2.1/nrpe-3.2.1.tar.gz
... or install NRPE on 22.04:
cd /opt https://github.com/NagiosEnterprises/nrpe/releases/download/nrpe-4.1.0/nrpe-4.1.0.tar.gz
tar zxf 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 sudo make install sudo make install-config sudo make install-init
Next, we need to update the config file to suite your needs:
vim /usr/local/nagios/etc/nrpe.cfg
Most important is this setting:
allowed_hosts=127.0.0.1,::1,<nagios_server_private_ip>
Finally, start nrpe and make sure everything started correctly:
systemctl start nrpe.service systemctl status nrpe.service … ● nrpe.service - Nagios Remote Plugin Executor Loaded: loaded (/lib/systemd/system/nrpe.service; disabled; vendor preset: enabled) Active: active (running) since Mon 2021-01-25 16:08:52 UTC; 8s ago
Now from the Nagios server, ensure you can see NRPE:
/usr/local/nagios/libexec/check_nrpe -H remote_host_ip NRPE v3.2.1