Active agent - unresponsive host trigger

[Fluze]

Hello All,

My situation as follows:
- Ubuntu x64 server 9.10
- Server and Agent 1.8.2, compiled from source
- Agent is configured as Active and is not listening on any ports (confirmed with netstat)
- In the server i have cloned the Linux template and updated the "Type" to "Agent (Active)" and have assigned the host.
- Communication is working as expected and triggers are working

The following simulation fails:
If i stop the agent, values are not flowing to the server -- expected
Some triggers are changing to unknown, as there is no data -- understandable, and expected
The problem: No triggers are changing to PROBLEM, so i am not aware the host went down.

What i am trying to do:
Say the agent is running behind a firewall. The firewall is pingable, but the server at wich the agent is running is locking up, crashing, whatever. The Agent is in any case not reporting data. I want to create a trigger that catches this event.

What i've tried:
- Create a trigger wich looks at the item agent.ping. The problem is that every calculation is always resulting 1, as that is the last received value. What i wanted to do was see how long ago that last value was received. For example: Trigger if the last received value is older that 2 minutes ago.
- Searched forums
- tried may other combinations of triggers/functions

Anyone any idea how to do that?

[richlv]

use item agent.ping;
use trigger function 'nodata' - for example, nodata(120) will mean agent not contacting the server for two minutes. of course, choose a period that would include at least a couple of values to reduce amount of trigger flipping

[Fluze]

Tested and working.

Thank you! That was exacly what i was looking for

[dweatherly]

I cannot see where to select no-data as a trigger function. I have quite a list, but that is not an option. Can someone help explain how to create this trigger? I am using 1.8.2

[Fluze]

It's not in the function list, you have to type in manually.
To do this, create a new trigger and in the Expression field click on the Select button. Select a item and initially select "Last value = N" and click OK. Now rename the function ".last(0)" to ".nodata(n)" where n is the number of seconds.

[dweatherly]

Perfect, thanks.