Compare Uptime for multiple devices

[pcpolo]

I am monitoring 6 network devices and need to know if one reboots for whatever reason.
How would I create a trigger to go off if the uptime for one device is different than the others?
Or if it's easier to alert if the uptime for 1 device is more than 20 seconds different (plus or minus) than the other 5.

Basically I just want to know if a device has rebooted when others haven't?
I know I can just monitor the uptime but I only want to be alerted if it does it unexpectedly.

[ghoz]

never tested but may work :
* create a group with the 6 devices,
* create one trigger with grpmax["my_6_device_group", "system.uptime" ,"last","0"] - grpmin ["my 6hosts", "system.uptime" ,"last","0"] > 20
=> you wont be able to know wich device has rebooted ...

or create a custom script that will check the values by snmp or zabbix_get and do some math for each device...

[pcpolo]

So I just create the trigger within one of the hosts?

[ghoz]

yes. or create a fake host so you won't think the problem
is on the one you setup the trigger for...

oh, and don't forget to report back if it works or not,
as I told you, I have never used these groupping functions ...

[pcpolo]

I made a group called: Test Group and then made a trigger and for the expression put:

grpmax["Test Group", "system.uptime" ,"last","0"] - grpmin ["Test Group", "system.uptime" ,"last","0"] > 20

And it is not working, I get:

Incorrect trigger expression.
Check expression part starting from " grpmax["Test Group", "system.uptime" ,"last","0"] - grpmin ["Test Group", "system.uptime" ,"last","0"] > 20 "