why is checking a URL failing when run through icinga? - nagios

Question

I created my own command to check a specific URL
define command{
command_name check_url
command_line /usr/lib/nagios/plugins/check_http -f follow -H '$HOSTNAME$' -I '$HOSTADDRESS$' -u '$ARG1$'
}
If I run my command from the command line, it works:
/usr/lib/nagios/plugins/check_http -f follow -H www.example.com -u http://www.example.com/server-status
HTTP OK: HTTP/1.1 200 OK - 4826 bytes in 0.011 second response time |time=0.010625s;;;0.000000 size=4826B;;;0
But when run through Icinga, I'm getting
HTTP WARNING: HTTP/1.1 404 NOT FOUND - 314 bytes in 0.011 second response time

Answer 1

My guess is for check_http plugin for -u option you should provide the url appended after the server name not the whole url.
Ex.
/usr/lib/nagios/plugins/check_http -f follow -H www.example.com -u /server-status

Answer 2

Your manual test is not equivalent to your command definition.
The distinction with -H/-I is subtle, but very important.

Answer 3

When I have problems like this, where Icinga is abstracting exactly how it is executing the command, I find it helpful to find out precicely what Icinga is executing. I would accomplish this as follows:
Move check_http to a temporary location
# mv /usr/lib/nagios/plugins/check_http /usr/lib/nagios/plugins/check_http_actual
Make a bash script that Icinga will call instead of the actual check_http script
# vi /usr/lib/nagios/plugins/check_http
In that file, create this simple bash script, which simply echos the command line arguments it was called with, then exits:
#!/bin/bash
echo $#
Then of course, make that bash script executable:
# chmod +x /usr/lib/nagios/plugins/check_http
Now in Icinga, run the check_http command. At that point, the return status shown in the Icinga web interface will show exactly how Icinga is calling check_http. Seeing the raw command, it should be obvious as to what Icinga is doing wrong. Once you correct Icinga's mistake, you can simply move the original check_http script back into place:
# mv /usr/lib/nagios/plugins/{check_http_actual,check_http}