As implemented for the reporting API functions, these are placeholder terms only and open for discussion.
- A system or group of systems being monitored. An entity can be as simple as a VM or as complex as a data center containing racks of servers running farms of VMs.
- A particular attribute of an entity which for which we care about changes in state
- Period of time from when a check goes into the `CRITICAL` state to when it comes out of that state again.
- Scheduled maintenance
- Periods of time explicitly created by external actors to denote that maintenance is scheduled to occur at these times.
- Unscheduled maintenance
- Periods of time explicitly created by external actors to denote that maintenance is happening or has happened at these times.
- Outages minus scheduled maintenances across any given time period.