What are the three pillars of observability in a software system?

What are the three pillars of observability in a software system?

• A. Logs, Metrics, Traces
• B. Logs, Metrics, Events
• C. Metrics, Traces, Events
• D. Logs, Metrics, Alerts

Answer: (A)

Observability rests on three kinds of signals: logs, metrics, and traces. Metrics provide time-series numbers that summarize how the system is performing over time—things like latency, error rate, and request throughput. They let you see trends, set thresholds, and alert on anomalies. Logs are detailed records of events that happened in the system, with context such as timestamps, identifiers, and messages, which you can search to understand exactly what occurred at a given moment. Traces track the path of a single request as it traverses multiple services, capturing how long each hop took and where delays or failures happened, so you can pinpoint bottlenecks across the call graph. Together these signals give a comprehensive picture: metrics show the big, ongoing health, traces reveal end-to-end performance, and logs provide the granular, contextual story of events. Events and alerts aren’t separate pillars; events often feed into logs or traces, and alerts are rules built on top of these signals to notify you when something looks off.

Observability rests on three kinds of signals: logs, metrics, and traces. Metrics provide time-series numbers that summarize how the system is performing over time—things like latency, error rate, and request throughput. They let you see trends, set thresholds, and alert on anomalies. Logs are detailed records of events that happened in the system, with context such as timestamps, identifiers, and messages, which you can search to understand exactly what occurred at a given moment. Traces track the path of a single request as it traverses multiple services, capturing how long each hop took and where delays or failures happened, so you can pinpoint bottlenecks across the call graph.

Together these signals give a comprehensive picture: metrics show the big, ongoing health, traces reveal end-to-end performance, and logs provide the granular, contextual story of events. Events and alerts aren’t separate pillars; events often feed into logs or traces, and alerts are rules built on top of these signals to notify you when something looks off.