Observability
#Logging
Logging is the act of recording information about an state/activity/object/action.
#Monitoring & Alerting
Monitoring is the act of searching (looking out) for presence/absence of patterns in information sources.
Alerting — the act of informing concerned parties about findings from monitoring. Like logging, monitoring enables alerting.
#Observability.
Observability of a system is the ability to observe the behavior/state of the system, and this is dictated by what the system exposes about itself.