Chapter 3. Nagios remote plug-in executor installation

Procedure

1. Install these packages on the node:

   [user@mon]# yum install openssl openssl-devel gcc make git

2. NRPE installation requires a Nagios user. So create the user first:

   [user@mon]# useradd nagios
   [user@mon]# passwd nagios

3. Download the latest version of the Nagios plug-ins. Then, make and install them:

   [user@mon]# wget http://www.nagios-plugins.org/download/nagios-plugins-2.2.1.tar.gz
   [user@mon]# tar zxf nagios-plugins-2.2.1.tar.gz
   [user@mon]# cd nagios-plugins-2.2.1
   [user@mon]# ./configure
   [user@mon]# make
   [user@mon]# make install

4. NRPE uses xinetd for communication. Install it before installing the NRPE module:

   [user@mon]# yum install xinetd

5. Download the latest verion of the Ceph plug-ins:

   [user@mon]# cd ~
   [user@mon]# git clone --recursive https://github.com/valerytschopp/ceph-nagios-plugins.git
   [user@mon]# cd ceph-nagios-plugins
   [user@mon]# make dist
   [user@mon]# make install

6. Download, make and install Nagios NRPE:

   [user@mon]# cd ~
   [user@mon]# wget https://github.com/NagiosEnterprises/nrpe/releases/download/nrpe-3.1.0/nrpe-3.1.0.tar.gz
   [user@mon]# tar xvfz nrpe-3.1.0.tar.gz
   [user@mon]# cd nrpe-3.1.0
   [user@mon]# ./configure
   [user@mon]# make all
   [user@mon]# make install-groups-users
   [user@mon]# make install
   [user@mon]# make install-config
   [user@mon]# make install-init

7. Edit the the /etc/services file, and add the service string nrpe 5666/tcp:

8. Open port 5666 to allow communication with NRPE:

   [user@mon]# firewall-cmd --zone=public --add-port=5666/tcp
   [user@mon]# firewall-cmd --zone=public --add-port=5666/tcp --permanent

Procedure

1. Enable, restart, and reload xinetd:

   [user@mon]# systemctl enable xinetd
   [user@mon]# systemctl restart xinetd
   [user@mon]# systemctl reload xinetd

2. Enable and start NRPE:

   [user@mon]# systemctl enable nrpe
   [user@mon]# systemctl start nrpe

Procedure

1. Edit the xinetd configuration with the Nagios server’s IP address:

   [user@mon]# vi /etc/xinetd.d/nrpe

   # default: off
   # description: NRPE (Nagios Remote Plugin Executor)
   service nrpe
   {
       disable         = yes
       socket_type     = stream
       port            = 5666
       wait            = no
       user            = nagios
       group           = nagios
       server          = /usr/local/nagios/bin/nrpe
       server_args     = -c /usr/local/nagios/etc/nrpe.cfg --inetd
       only_from       = 127.0.0.1,IP_ADDRESS_OF_NAGIOS_CORE_SERVER
       log_on_success  =
   }

2. After adding the IP address of the Nagios Core server to the only_from option, restart the xinetd service:

   [user@mon]# systemctl restart xinetd

3. Edit the NRPE configuration with the Nagios server’s IP address:

   [user@mon]# vi /usr/local/nagios/etc/nrpe.cfg

   allowed_hosts=127.0.0.1,IP_ADDRESS_OF_NAGIOS_CORE_SERVER

4. Add the IP address of the Nagios Core server to the allowed_hosts setting. Then, restart nrpe:

   [user@mon]# systemctl restart nrpe

5. Test the installation:

   [user@host]# /usr/local/nagios/libexec/check_nrpe -H localhost

   The check should echo NRPE v3.1.0-rc1 if it is working correctly.