[Nagiosplug-devel] RFC: Nagios 3 and Embedded Perl Plugins

[Thomas Guyot-Sionnest]

On 08/01/07 07:02 AM, Andreas Ericsson wrote:
> Stéphane Urbanovski wrote:
>> Andreas Ericsson a écrit :
>>
>>> But you just said to load this newfangled dream-version of nrpe as a 
>>> module? That sort of microsoft'ish thinking leads to "integrated" and 
>>> very unstable code I'm afraid.
>> (Ok, my english is really poor ...)
>>
>> Not the "newnrpe", wich is a separate process, but only the communication with newnrpe part
>>
> 
> Ah, I see what you mean now. I'm afraid that fairly drastically reduces 
> the scalability of Nagios. Assume for a second that you have 1500 hosts 
> to monitor, all of which use NRPE for checking local stuff. Keeping up 
> the connection with those 1500 hosts requires 1500 open file-descriptors 
> at all times. Most systems can have a lot more files than that open per 
> process at any given time, but there is still a hard limit lurking 
> somewhere which means Nagios can no longer check an arbitrary number of 
> hosts and services. The worst part is that that hard limit will be set 
> differently on different systems.
> 
> I'm afraid you'll find that this just isn't useful enough to warrant the 
> massive developer effort it would take to write it and seeing as you're 
> the only one arguing your case, you'd have to write it yourself to get 
> it implemented. Either way, further discussion is fairly pointless until 
> you have some code available.

Actually I think now it's getting interesting. If done properly, this
could be a nice way of doing distributed active checking.

Using the same system Stéphane described Nagios could have open
connections to remote execution hosts that runs the checks and read back
results. Different services properties would determine if the service
can be run directly on the host (if Nagios has an open connection to it)
or if it has to be remote. Check execution load could be run on
dedicated servers, or even be spread out across monitored hosts.

On big setups this had the clear advantage of scalability, but on
smaller setups it can also be interesting as one could use very cheap
servers for running the Nagios daemon in HA, and provide redundancy by
spreading the checks across monitored servers themselves.

Thomas