Observability es la capacidad de entender el estado interno de un sistema a partir de sus salidas externas — a través de logs, metrics y traces. Es esencial para operar, depurar y mantener sistemas (especialmente los distribuidos), donde no puedes gestionar lo que no ves.
Por qué es importante
LOGS → timestamped records of events (what happened) → detailed, for debugging specific issues
METRICS → numerical measurements over time (CPU, latency, request rate, error rate) →
aggregate health/performance; dashboards; alerting
TRACES → follow a request's path through the system (across services) → understand flows,
find bottlenecks/failures in DISTRIBUTED systems (which service was slow?)
→ together: understand WHAT happened, the OVERALL state, and the PATH of requests.
