Hi Services team!

While reviewing AQS alarms I noticed that Analytics created some CQL probes and the cassandra::instance module was already providing some. All the context is in https://gerrit.wikimedia.org/r/#/c/292568

After a long discussion it would be great to spend a bit of time thinking if a specific cassandra::monitoring class would give use more flexibility. A role could include cassandra::instance and decide to use the cassandra::monitoring class (configuring it with specific parameters like the nrpe_monitoring contact_group) or just to use a separate module.

Use case that generated the discussion: Analytics would like to add its nagios contact to the cassandra default one "admins,team_services" but there is no way to do it at the moment. Parametrizing the contact_group would be an option but what if somebody else comes up with a similar use case? A completely configurable cassandra::monitoring class would probably be more flexible in the longer term.