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

Procedure

1. Log in to the Ceph monitor host and create a Ceph key and keyring for Nagios.

   Example

   [root@nagios ~]# ssh user@host01
   [user@host01 ~]$ sudo su -
   [root@host01 ~]# cd /etc/ceph
   [root@host01 ceph]# ceph auth get-or-create client.nagios mon 'allow r' > client.nagios.keyring

   Each plug-in will require authentication. Repeat this procedure for each host that contains a plug-in.

2. Add a command for the check_ceph_health plug-in:

   Example

   [root@host01 ~]# vi /usr/local/nagios/etc/nrpe.cfg

   command[check_ceph_health]=/usr/lib/nagios/plugins/check_ceph_health --id nagios --keyring /etc/ceph/client.nagios.keyring

3. Enable and restart the nrpe service:

   Example

   [root@host01 ~]# systemctl enable nrpe
   [root@host01 ~]# systemctl restart nrpe

   Repeat this procedure for each Ceph plug-in applicable to the host.

4. Return to the Nagios Core server and define a check_nrpe command for the NRPE plug-in:

   Example

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

   Syntax

   define command{
    command_name check_nrpe
    command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
   }

5. On the Nagios Core server, edit the configuration file for the node and add a service for the Ceph plug-in.

   Example

   [root@nagios objects]# vi /usr/local/nagios/etc/objects/host01.cfg

   Syntax

   define service {
     use                   generic-service
     host_name             HOSTNAME
     service_description   Ceph Health Check
     check_command         check_nrpe!check_ceph_health
   }

   Replace HOSTNAME with the hostname of the Ceph host you want to monitor.

   Example

   define service {
     use                   generic-service
     host_name             host01
     service_description   Ceph Health Check
     check_command         check_nrpe!check_ceph_health
   }

   Note

   The check_command setting uses check_nrpe! before the Ceph plug-in name. This tells NRPE to execute the check_ceph_health command on the remote node.

6. Repeat this procedure for each plug-in applicable to the host.

7. Restart the Nagios Core server:

   Example

   [root@nagios ~]# systemctl restart nagios

8. Before proceeding with additional configuration, ensure that the plug-ins are working on the Ceph host:

   Syntax

   /usr/lib/nagios/plugins/check_ceph_health --id NAGIOS_USER --keyring /etc/ceph/client.nagios.keyring

   Example

   [root@host01 ~]# /usr/lib/nagios/plugins/check_ceph_health --id nagios --keyring /etc/ceph/client.nagios.keyring
   HEALTH OK

   Note

   The check_ceph_health plug-in performs the equivalent of the ceph health command.