Observability & Monitoring

Monitoring tells you whether a known condition is true. Observability is whether you can answer a new question about your system without shipping new code. Most teams have plenty of the first and very little of the second.

In practice that means recording metrics with enough dimensions to slice by, alerting on symptoms users feel rather than on causes, and being able to correlate a change in a graph with a change in the system. A dashboard nobody looks at during an incident is not observability.