Very simple, just performs a quick check of all critical service dependancies (filesystem, DB, caches, and sessions) and return OK
Use from a load balancer to tell whether a node is OK
Just install the plugin normally and then point your load balance to a url like this:
http://moodle.example.com/admin/tool/heartbeat/
It will return a page with either a 200 or 503 response code and if it fails a string for why.
By default it only performs a light check, in particular it does not check the moodle database. To do a full check add this query param:
http://moodle.example.com/admin/tool/heartbeat/?fullcheck
This check can also be run as a CLI:
php index.php fullcheck
A script croncheck is a nagios compliant checker to see if cron or any individual tasks are failing, with configurable thresholds
This script can be either run from the web:
http://moodle.example.com/admin/tool/heartbeat/croncheck.php
Or can be run as a CLI in which case it will return in the format expected by Nagios:
sudo -u www-data php /var/www/moodle/admin/tool/heartbeat/croncheck.php
The various thresholds can be configured with query params or cli args see this for details:
php croncheck.php -h
Via the Moodle plugin directory: