how can an NRPE script know the remote server's IP?

[RichTea]

On Sat, Apr 28, 2012 at 2:38 AM, Morty <morty+nagios at frakir.org> wrote:

> Is there a way for an NRPE script to know the remote server's IP?  I'm
> not seeing anything in the environment for NRPE 2.12.  getpeername on
> STDIN doesn't seem to help; presumably nrpe doesn't connect the script
> directly to the sockets.
>
> Detailed scenario:
>
> I have two nagios servers running in an active/active cluster.  So
> each nagios instance is checking all servers.  Some services utilize
> NRPE.  One service check is a script that wants to see change in a
> certain system parameter since last time.  It then saves the value in
> a statefile, so it can check the next time.
>
> Problem: race condition.  If the two nagios servers both check at
> around the same time, one of them will set the state file.  Then the
> other one sees the recent statefile and sees no change in the system
> parameter, and the service check goes critical.
>
> A lockfile won't solve the problem, because the problem isn't when the
> two are running at the same time, it's when the two run shortly after
> one another.
>
> One fix would be to have the script use a statefile that includes the
> nagios server IP.  So it would use a different statefile depending on
> which nagios server queries, and there would be no conflict.  The
> problem is, I can't see a way to supply the server IP to the script.
> No such variable appears in the NRPE environment.  getpeername isn't
> working, at least on STDIN.
>
> I could try to do something with a nagios macro, but NRPE scripts are
> supposed to have fixed options unless I turn on dont_blame_nrpe=1,
> which I don't want to do.
>
> - Morty
>


dont_blame_nrpe isnt that big a security issue if you trust your Nagios
servers security and restrict whos allowed to run nrpe commands.
You could then pass in a custom macro from Nagios.

The only other way I could think would be to run a different client side
check / service for each Nagios server.

if you use the _exact_ same config on each Nagios server you can probably
use a custom macro in the service's command definition.

I have not tried it my self but i dont see why it wont work.

service {
name statefile
command $USER1$/statefile_$USER5$.pl
}

where $USER5$ is set to the Nagios servers host name and just define two
nrpe commands on the client's.


HTH
Ritchie,
--
<--Time flies like an arrow; fruit flies like a banana.  -->



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