Sometimes we need to monitoring public area services, such as http, ftp. We can not install the client side agent on the public server, anyway, we can monitoring the status of them by some plugins.
Http service
1. Define the check_http command
# 'check_http' command definition
define command{
command_name check_http
command_line $USER1$/check_http -H $HOSTADDRESS$ $ARG1$
}
2. create a host configuration file for the webserver
cd /usr/local/nagios/etc/objects/
then create a configuration file for your webserver, I name it as test.cfg, the usl of the website is www.test.com
define host {
use linux-server ; Inherit default values from a template
host_name test ; The name we're giving to this host
alias test ; A longer name associated with the host
address xxx.xxx.xxx.xxx ; IP address of the host
}
Http
define service {
use generic-service ; Inherit default values from a template
host_name test
service_description HTTP
check_command check_http!www.test.com
}
If you also want to test the sub pages, eg. www.test.com/news/, use switch -u
define service {
use generic-service ; Inherit default values from a template
host_name au123
service_description news
check_command check_http!www.test.com -u http://www.test.com/news/
}
Https
To monitor the https service, add -S switch.
check_command check_http!www.test.com -S
Check service on different port
Use switch -p port_number
Certificate validation
You can check whether a SSL certificate of the website expires within the next X number of days with switch -C.
check_http -H google.com -C 200
The result will be either Ok or warning.
3. Let the nagios load the configuration file
vi /usr/local/nagios/etc/nagios.cfg
Then add following lines:
# Definitions for monitoring website cfg_file=/usr/local/nagios/etc/objects/test.cfg
Reference
https://assets.nagios.com/downloads/nagioscore/docs/nagioscore/4/en/monitoring-publicservices.html