Glossary
The property of a system to reveal from the outside what is happening inside, including for questions nobody asked in advance.
The difference to classic monitoring is the kind of question. Monitoring answers prepared questions, such as whether response time exceeds a threshold. Observability allows new questions afterwards, such as why customers from one region have been waiting longer since yesterday.
It rests on three kinds of data: metrics, logs and tracing across service boundaries. What matters is that they can be joined through a shared identifier.
How you notice it
Frequently asked
A shared identifier across all services. Without it, logs and metrics are two collections nobody can join. With it a single transaction can be followed through the system, and that answers most questions during an outage.