Nagios provides a scheduler that runs check on a regular basis and write those check results into it's database. This is called Active Checks.
It has a second mode called Passive Checks where an external system performs the checks and writes the result to it's command file.
This is a system that uses MCollective and the Rufus scheduler to build a distributed async scheduler and checker for Nagios based on the Passive mode. This approach will scale better and perform all checks of a specific plugin at more or less the same time thanks to the basic nature of MCollectives broadcast system.
All communications between the scheduler, nodes and receivers are secured using your MCollective security infrastructure and authorization to run checks are done using the MCollective Authorization system.
This is still not complete, check back for more information later
This isn't some magical make-nagios-suck-less thing, you still need to configure every service to receive the Passive Checks in Nagios else it will just discard the Passive Results for non existing hosts or services.
Your MCollective identifies need to match up with what you have called your hosts in Nagios as it will simply use the identities for host names in the Passive Results.
If your NRPE check command is called check_load then this system will submit a passive check to the load service.
The scheduler isn't aware of your Nagios config so if you add a check somewhere you should also add it to the checks file. The core idea is that we find that many hosts have common checks across batches of them, this system will optimise and scale the gathering of those results.
You need MCollective fully working with the NRPE 2.2 or newer plugin deployed. This system uses MCollective libraries for configuration, logging, security and communications.
Depending on your MCollective security setup you might need to run the scheduler and the receiver using the same client.cfg sharing properties like SSL certificates and such.
Apart from the basic MCollective setup you can also set the following:
plugin.mnrpes.nagios.command_file = /var/spool/nagios/rw/nagios.cmd plugin.mnrpes.reply_queue = /queue/mcollective.nagios_passive_results
This affects where your Nagios command_file file is and what Stomp destination is being used to transport check results.
The output handling is handled using plugins. By default it uses the nagios output as described here but there are some others, see the output directory, you can choose a different output handler:
plugin.mnrpes.processors = stdout
The processors can be a list like:
plugin.mnrpes.processors = stdout,nagios
Which means both plugins will get the data.
For best results you would want to run MCollective 2.1.1 at least and one of the new Discovery Plugins that does discovery against a local cache like MongoDB or PuppetDB.
This way you will not be doing costly discoveries against the network all the time and get consistant host lists.
Checks live in a simple file, an example can be seen below:
nrpe "check_swap", "1m" nrpe "check_load", "1m" nrpe "check_bacula_main", "6h", "bacula::node"
Here we create 3 checks with different intervals, the last one has a MCollective filter applied, the filter syntax matches that of the -W argument to the MCollective command line.
The scheduler takes a --checks option that is the path to this file