Can I directly compare 2 items values in a trigger?

[Farzad FARID]

Hi,

In all default trigger examples the formulas for comparison involve an item and a fixed value (eg: Unix_t:vm.memory.size[free].last(0)<10000).

Can I use the mathematic formulas to directly compare two items to each other in order to build a trigger? There are case where the limit value to be compared to is also a dynamique value.

For example (just a useless one that comes to my mind):

Expression : net.if.in[eth0,bytes].last(0) > net.if.in[eth1,bytes].last(0)

A real use would be to retrieve two values from a JBoss application server (number of active DB connections and maximum number of supported DB connections), and compare them to check if the application server is overloaded.

Regards

[Farzad FARID]

Yes it works

Hi, and happy New Year to all of you

I reply to my own question 8 months later, because a friend of mine had the same question, and only found my unanswered question instead of a definitive answer

So the answer is Yes, it works. But you have to enter the expression manually, because the GUI helper only lets you enter a constant value on the right hand side of the comparison.

Here is a real example. The comparison is meaningless in the real world (I compare the User Space CPU percentage to the Idle CPU percentage), but it is easy to trigger in a test situation:

{dedibox_t:system.cpu.util[,user,avg1].last(0)} > {dedibox_t:system.cpu.util[,idle,avg1].last(0)}

Regards

[r3dn3ck]

you can also do the basic 4 function math with -+/* in place of the comparison operator.

[MarkusL]

Hi r3dn3ck!

Do you know, if it´s possible to do math-functions within a comparison.

F.e. I want to check Terminalserver-Load-Balancing. For that I could make two triggers:

({terminalserver1:active-sessions[].last(0)} +3) < {terminalserver2:active-sessions[].last(0)}

({terminalserver2:active-sessions[].last(0)} +3) < {terminalserver1:active-sessions[].last(0)}

With that I would check: if on one terminalserver all sessions together +3 is still smaller than all active sessions on the other terminalserver, please report that. Loadbalancer should have max. 2 sessions more on one of the servers,... Otherwise loadbalancing is not ok.


Thanks,
kind regards,

Markus.

[esimim2]

To compare items in two different hosts you use the function "Last (most recent) T value is = N". Then in the constructor you edit the expression adding the item do the right:

{host1:sequence.last()}>{host1:sequence.last()}+10

King regards to the community,

Eliandro.

[magrif]

Hi everyone.
What about some like: {host:logrt["/var/log/auth.log", "failed"].regexp("{host:system.run[echo User123].last()}")}=1? It's possible?
Thanks!