Monitoring Windows machines

Monitoring Netware servers

Monitoring Linux/Unix machines

Monitoring HTTP

Chances are you're going to want to monitor web servers at some point - either yours or someone else's. The check_http plugin is designed to do just that. It understands the HTTP protocol and can monitor response time, error codes, strings in the returned HTML, server certificates, and much more.

The commands.cfg file contains a command definition for using the check_http plugin. It looks like this:

 define command{
        name            check_http
        command_name    check_http
        command_line    $USER1$/check_http -I $HOSTADDRESS$ $ARG1$
        }

A simple service definition for monitoring the HTTP service on the remotehost machine might look like this:

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     HTTP
        check_command           check_http
        }

This simple service definition will monitor the HTTP service running on remotehost. It will produce alerts if the web server doesn't respond within 10 seconds or if it returns HTTP errors codes (403, 404, etc.). That's all you need for basic monitoring. Pretty simple, huh?

	Tip
	For more advanced monitoring, run the check_http plugin manually with --help as a command-line argument to see all the options you can give the plugin. This --help syntax works with all of the plugins we'll cover in this document.

A more advanced definition for monitoring the HTTP service is shown below. This service definition will check to see if the /download/index.php URI contains the string "latest-version.tar.gz". It will produce an error if the string isn't found, the URI isn't valid, or the web server takes longer than 5 seconds to respond.

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     Product Download Link
        check_command           check_http!-u /download/index.php -t 5 -s "latest-version.tar.gz"
        }

Monitoring FTP

When you need to monitor FTP servers, you can use the check_ftp plugin. The commands.cfg file contains a command definition for using the check_ftp plugin, which looks like this:

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

A simple service definition for monitoring the FTP server on remotehost would look like this:

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     FTP
        check_command           check_ftp
        }

This service definition will monitor the FTP service and generate alerts if the FTP server doesn't respond within 10 seconds.

A more advanced service definition is shown below. This service will check the FTP server running on port 1023 on remotehost. It will generate an alert if the server doesn't respond within 5 seconds or if the server response doesn't contain the string "Pure-FTPd [TLS]".

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     Special FTP 
        check_command           check_ftp!-p 1023 -t 5 -e "Pure-FTPd [TLS]"
        }

Monitoring SSH

When you need to monitor SSH servers, you can use the check_ssh plugin. The commands.cfg file contains a command definition for using the check_ssh plugin, which looks like this:

 define command{
        command_name    check_ssh
        command_line    $USER1$/check_ssh $ARG1$ $HOSTADDRESS$
        }

A simple service definition for monitoring the SSH server on remotehost would look like this:

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     SSH
        check_command           check_ssh
        }

This service definition will monitor the SSH service and generate alerts if the SSH server doesn't respond within 10 seconds.

A more advanced service definition is shown below. This service will check the SSH server and generate an alert if the server doesn't respond within 5 seconds or if the server version string string doesn't match "OpenSSH_4.2".

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     SSH Version Check 
        check_command           check_ssh!-t 5 -r "OpenSSH_4.2"
        }

Monitoring SMTP

The check_smtp plugin can be using for monitoring your email servers. The commands.cfg file contains a command definition for using the check_smtp plugin, which looks like this:

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

A simple service definition for monitoring the SMTP server on remotehost would look like this:

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     SMTP
        check_command           check_smtp
        }

This service definition will monitor the SMTP service and generate alerts if the SMTP server doesn't respond within 10 seconds.

A more advanced service definition is shown below. This service will check the SMTP server and generate an alert if the server doesn't respond within 5 seconds or if the response from the server doesn't contain "mygreatmailserver.com".

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     SMTP Response Check 
        check_command           check_smtp!-t 5 -e "mygreatmailserver.com"
        }

Monitoring POP3

The check_pop plugin can be using for monitoring the POP3 service on your email servers. The commands.cfg file contains a command definition for using the check_pop plugin, which looks like this:

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

A simple service definition for monitoring the POP3 service on remotehost would look like this:

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     POP3
        check_command           check_pop
        }

This service definition will monitor the POP3 service and generate alerts if the POP3 server doesn't respond within 10 seconds.

A more advanced service definition is shown below. This service will check the POP3 service and generate an alert if the server doesn't respond within 5 seconds or if the response from the server doesn't contain "mygreatmailserver.com".

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     POP3 Response Check 
        check_command           check_pop!-t 5 -e "mygreatmailserver.com"
        }

Monitoring IMAP

The check_imap plugin can be using for monitoring IMAP4 service on your email servers. The commands.cfg file contains a command definition for using the check_imap plugin, which looks like this:

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

A simple service definition for monitoring the IMAP4 service on remotehost would look like this:

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     IMAP
        check_command           check_imap
        }

This service definition will monitor the IMAP4 service and generate alerts if the IMAP server doesn't respond within 10 seconds.

A more advanced service definition is shown below. This service will check the IAMP4 service and generate an alert if the server doesn't respond within 5 seconds or if the response from the server doesn't contain "mygreatmailserver.com".

 define service{
        use                     generic-service         ; Inherit default values from a template
        host_name               remotehost
        service_description     IMAP4 Response Check 
        check_command           check_imap!-t 5 -e "mygreatmailserver.com"
        }