Create a simple Nagios plugin support graph (passive check)

First, to know this article, please read and practice active check in here.

Config passive check
Config with nagios core:

vi /usr/local/nagios/etc/nagios.cfg

accept_passive_service_checks option is set to 1 as well.



Manual passive check

Create a plugin like active check article but in define service add two lines:

active_checks_enabled 0
passive_checks_enabled 1

Restart nagios:

sudo -s
service nagios restart

This is the result:

 Click Submit passive check and fill it like this image:

 refresh nagios webpage and wait few seconds and view Status information:

Other way:
Structure:

[<timestamp>] PROCESS_SERVICE_CHECK_RESULT;<host_name>;<service_description>;<service_status>;<plugin_output>

Example:

sudo -s
CHECK="[`date +%s`] PROCESS_SERVICE_CHECK_RESULT;localhost2;Check cpu;0;Ok from commandline"
echo $CHECK >>/usr/local/nagios/var/rw/nagios.cmd

Passive check from remote host

Nagios server (ip: 192.168.0.221)
Install

sudo -s
apt-get install nsca

Edit nsca config:

vi /etc/nsca.cfg

Content to change (if different), can change password to anythink you like but must match client and server:

command_file=/usr/local/nagios/var/rw/nagios.cmd

password=aloha

decryption_method=1
nsca_group=nagios
nsca_user=nagios

Restart nsca

service nsca restart

Client (ip: 192.168.0.33)
Install:

sudo -s
apt-get install nsca-client

Config:

 vi /etc/send_nsca.cfg

change password and encryption_method like server

Check

echo -en "localhost2\tcheck cpu\t0\tCheck Ok from nsca\n" | send_nsca -c /etc/send_nsca.cfg -H 192.168.0.221

Result Ok, but nagios don't do any think.

1 data packet(s) sent to host successfully.

Debug: 

 vi /usr/local/nagios/var/nagios.log

[1377855543] EXTERNAL COMMAND: PROCESS_SERVICE_CHECK_RESULT;localhost2;check cpu;0;Check111 Ok from nsca

[1377855543] Warning: Passive check result was received for service 'check cpu' on host 'localhost2', but the service could not be found!

and this is the reason:

 echo -en "localhost2\tCheck cpu\t0\tCheck Ok from nsca\n" | send_nsca -c /etc/send_nsca.cfg -H 192.168.0.221

Wait for few seconds and data will be update in nagios.
You can see in active check article to see how to create graph.