Strange UserParameter issue

[Akaban]

Hey people

I have some strange issue on my zabbix installation, everything's going great apart from a thing. I have a dhcp server on a virtual machine and I want to monitor if this service is available or not, so I went on the VM and modified the zabbix agent configuration with something like that,

UserParameter=dhcp,ps -fu dhcpd | grep dhcpd | wc -l

Sounds simple enough, entering this on my command line prompt and I get the desired result. The problem is that Zabbix is always reporting me the value "0" which is not what I want since theses commands do not return that at the moment (they return 1 because it is actually running)

So I went debugging mode and found something interesting,

26936:20140719:014537.355 Run remote command [ps -fu dhcpd | grep dhcpd | wc -l] Result [1] [0]...
26936:20140719:014537.355 Sending back [0]

So Zabbix Agent did run my command but it seems like it's saying it returns two results, 0 and 1. What is that for?

Also he's sending the result I do not want: 0.

Could anyone explain me why did Zabbix had this behavior?

instead the simple,

UserParameter=dhcp,echo 1

works great and successfully return 1. I really do not understand...

Any help would be greatly appreciated

++

[aib]

Did you try to use some internal function, like proc.num ?

https://www.zabbix.com/documentation/2.2/manual/config/items/itemtypes/zabbix_agent?s[]=proc.num

[Akaban]

Hi !

Thanks you for your answer. Unfortunately it also returns 0 Thanks to the link you posted I tried vfs.file.exists on /var/run/dhcpd.pid. It won't work if the service is killed brutally but I don't think that is an issue.

Thanks Problem solved !