O11y, shorthand for Observability - O + 11 letters + y :-)
Observability is the ability to understand the internal state of a system by examining only the data it outputs.
Three Pillars #
Metrics #
Quantitative measurements collected over time. Useful for dashboards, alerts, and trend analysis.
Traces #
Traces show the journey of a request through a system. Comprised of spans, which represent operations. Useful for understanding latency, bottlenecks, and dependencies.
Logs #
Text records of events in an application. Structured logs (e.g., JSON) are preferred. Critical for debugging and incident analysis.