Chapter 4. Configuring the remote node on the Nagios Core server

Procedure

1. Install the check_nrpe plug-in:

   Example

   [root@nagios ~]# cd ~
   [root@nagios ~]# wget https://github.com/NagiosEnterprises/nrpe/releases/download/nrpe-4.0.3/nrpe-4.0.3.tar.gz
   [root@nagios ~]# tar xvfz nrpe-4.0.3.tar.gz
   [root@nagios ~]# cd nrpe-4.0.3
   [root@nagios nrpe-4.0.3]# ./configure
   [root@nagios nrpe-4.0.3]# make check_nrpe
   [root@nagios nrpe-4.0.3]# make install-plugin

2. Create a configuration for the remote host:

   Syntax

    cd /usr/local/nagios/etc/objects
    cp localhost.cfg HOST_TO_ADD.cfg

   Example

   [root@nagios nrpe-4.0.3]# cd /usr/local/nagios/etc/objects
   [root@nagios objects]# cp localhost.cfg host01.cfg

3. Edit the configuration file and update the settings for the remote host:

   Syntax

   vi HOST_TO_ADD.cfg

   Example

   [root@nagios objects]# vi host01.cfg

   Syntax

   # Define a host for the local machine
   
   define host {
   
       use     linux-server    ; Name of host template to use
                               ; This host definition will inherit all variables that are defined
                               ; in (or inherited by) the linux-server host template definition.
       host_name               LOCALHOST
       alias                   LOCALHOST
       address                 127.0.0.1
   }

   Replace LOCALHOST with the hostname of the remote host, and 127.0.0.1 with the IP address of the Ceph monitor host.

   Example

   # Define a host for the local machine
   
   define host {
       use     linux-server   ; Name of host template to use
                              ; This host definition will inherit all variables that are defined
                              ; in (or inherited by) the linux-server host template definition.
       host_name               host01
       alias                   host01
       address                 10.10.128.69
   }

4. Delete or comment out the Host Group definition:

   Example

   [root@nagios objects]# vi host01.cfg

   #define hostgroup {
   #
   #    hostgroup_name          linux-servers           ; The name of the hostgroup
   #    alias                   Linux Servers           ; Long name of the group
   #    members                 localhost               ; Comma separated list of hosts that belong to this group
   #}

5. Change the file ownership to Nagios:

   Example

   [root@nagios objects]# chown nagios:nagios host01.cfg

6. Add a cfg_file= reference to the host01.cfg file in /usr/local/nagios/etc/nagios.cfg:

   Example

   [root@nagios objects]# vi /usr/local/nagios/etc/nagios.cfg

   cfg_file=/usr/local/nagios/etc/objects/host01.cfg

7. Restart the Nagios server:

   Example

   [root@nagios objects]# systemctl restart nagios

8. Ensure that the make and install procedures worked and that there is connectivity between the Nagios Core server and the remote host containing NRPE:

   Syntax

   /usr/local/nagios/libexec/check_nrpe -H HOSTNAME_OF_REMOTE_HOST

   Replace HOSTNAME_OF_REMOTE_HOST with the IP address of the Ceph host to monitor.

   Example

   [root@nagios objects]# /usr/local/nagios/libexec/check_nrpe -H host01