Monitoring Windows through NSCP 5 using Nagios 4.2 on CentOS/RHEL

This article will cover the complete procedure for NSClient++ installation and configuration on Windows 7, 8 or 10 operating systems followed by verification and operation modes through the respective Nagios plugin and protocol on CentOS 7.

WINDOWS

First of all, download the most recent NSCP stable release (either 32 or 64 bits) from the following link

https://www.nsclient.org/download/

When the download is completed, run the installer and select the recommended options

In the next screen, one or more hosts may be allowed to query the NSCP machine with or without a password protection (for the NTServer module). In our case, we’re going t0 define a password to be utilized with the check_nt command, as will be shown later

After the installation process is finished, browse to the “NSClient++” directory – found in “Program Files” – and edit the “nsclient.ini” file as follows

; TODO
[/settings/default]

; Undocumented key
password = nagiosscp

; Undocumented key
allowed hosts = 192.168.0.200

; TODO
[/settings/NRPE/server]

allow arguments = true

; Undocumented key
verify mode = none

; Undocumented key
insecure = true

; TODO
[/modules]

; Undocumented key
CheckExternalScripts = 1

; Undocumented key
CheckHelpers = 1

; Undocumented key
CheckEventLog = 1

; Undocumented key
CheckNSCP = 1

; Undocumented key
CheckDisk = 1

; Undocumented key
CheckSystem = 1

; Undocumented key
NRPEServer = 1

Save the file while closing and restart the NSClient++ service in order to apply the changes

CentOS (CLI)

Login as root or, alternatively, switch accounts using the following command

su -l

Having Nagios Core and NRPE Client installed – as oriented by the Setting up Client and Daemon NRPE article -, check if the “check_nt” and “check_nrpe” scripts are stored in the default directory

cd /usr/local/nagios/libexec/

grep check_nt

grep check_nrpe

Otherwise, retrace your steps provided by the current and suggested guides from the beginning

Below are collected some of the operation modes for each of the “check” commands along with a brief description about their function

Select one of the operation modes listed for both “checks” and execute a command/service sample in order to verify the communication and configuration of the machines

/usr/local/nagios/libexec/check_nt -H 192.168.0.100 -p 12489 -s nagiosscp -v USEDDISKSPACE -l c -w 80 -c 90

/usr/local/nagios/libexec/check_nrpe -H 192.168.0.100 -p 5666 -t 20 -c CheckDriveSize -a Drive=C: MinWarn=100G MinCrit=50G

Closing the previous steps successfully, edit the “check_nt” command and add an entry for the “check_nrpe” right below it in Nagios “commands.cfg”

vim /usr/local/nagios/etc/objects/commands.cfg

{LINES 207 TO 215}
define command{
        command_name    check_nt
        command_line    $USER1$/check_nt -H $HOSTADDRESS$ -p 12489 -s nagiosscp -v $ARG1$ $ARG2$
        }

define command{
        command_name    check_nrpe
        command_line    $USER1$/check_nrpe -H $HOSTADDRESS$ -p 5666 -t 20 -c $ARG1$ -a $ARG2$
        }

Now create a hosts/services “.cfg” file adding the definitions shown next

vim /usr/local/nagios/etc/objects/tempnscp.cfg

define host{
	use		generic-host
	max_check_attempts      10
        check_interval          5
        retry_interval          1
	host_name	winnscp	; The name we're giving to this host
	alias		Windows NSClient++	; A longer name associated with the host
	address		192.168.0.100	; IP address of the host
	}

#check_nt services

define service{
	use			generic-service
	host_name		winnscp
	service_description	CPU Load - NT
	check_command		check_nt!CPULOAD!-l 5,80,90
	}

define service{
	use			generic-service
	host_name		winnscp
	service_description	Memory usage - NT
	check_command		check_nt!MEMUSE!-w 50 -c 90
	}

define service{
        use                     generic-service
        host_name               winnscp
        service_description     Used space in drive C - NT
        check_command           check_nt!USEDDISKSPACE!-l c -w 80 -c 90
        }

#check_nrpe services

define service{
        use                     generic-service
        host_name               winnscp
        service_description     CPU Load - NRPE
        check_command           check_nrpe!checkcpu!MaxWarn=80 MaxCrit=90
        }

define service{
        use                     generic-service
        host_name               winnscp
        service_description     Memory usage - NRPE
        check_command           check_nrpe!checkmem!type=committed MinWarn=50 MinCrit=10
        }

define service{
        use                     generic-service
        host_name               winnscp
        service_description     Used space in drive C - NRPE
        check_command           check_nrpe!checkdrivesize!Drive=c: MinWarn=100G MinCrit=50G
        }

Don’t forget to declare the new data into the Nagios main config file !

vim /usr/local/nagios/etc/nagios.cfg

{LINE 36}
cfg_file=/usr/local/nagios/etc/objects/tempnscp.cfg

Preparations done, restart Nagios service

 service nagios restart

After successfully completing the procedures, you must be able to see the setup services through the web interface

http://192.168.0.200/nagios

For any troubleshooting regarding these steps, refer to the official NSClient documentation found at:

http://docs.nsclient.org/