Logging Fundamentals
Logging records events from applications, operating systems, and devices. Those records help you understand what happened, investigate failures, and detect security-relevant activity.
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Intro
Logging Fundamentals
A log is a recording of an event. An application can record a completed request, a failed sign-in, or a configuration change. An operating system or device can record its own events. Each record preserves context that you can inspect later.
Logging turns runtime activity into evidence. You use that evidence to troubleshoot failures, investigate security events, audit important changes, and understand system behavior. A log is not the event itself. It is the record the source chose to emit.
That distinction matters. Missing records do not prove that nothing happened. A record can also be delayed, duplicated, truncated, or dropped. Treat logs as evidence with known limits.
One event, one useful record
A useful log record answers a small set of questions:
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Sources
- https://opentelemetry.io/docs/concepts/signals/
Supports
- Logs as recordings of events
- Distinctions among logs, metrics, and traces
- https://opentelemetry.io/docs/specs/otel/logs/data-model/
Supports
- Log record timestamps, severity, body, resource, attributes, and trace context
- Structured bodies and mappings from existing log formats
- https://opentelemetry.io/docs/specs/otel/logs/
Supports
- Collection of application, system, and infrastructure logs
- Log correlation with trace, span, resource, and application context
- https://www.rfc-editor.org/rfc/rfc5424.html
Supports
- Syslog's layered architecture, message format, and structured data
- Truncation, transport, congestion, blocking, and message-loss considerations
- https://cheatsheetseries.owasp.org/cheatsheets/Logging_Cheat_Sheet.html
Supports
- Security logging purposes, event and field selection, and data exclusions
- Injection resistance, failure testing, access controls, transport protection, retention, and disposal
- https://csrc.nist.gov/pubs/sp/800/92/final
Supports
- Enterprise log management infrastructure and processes
- Policy, planning, implementation, maintenance, and operational use
- https://github.com/sindresorhus/awesome
Supports
- Starting index used to discover topic-relevant awesome lists
- https://github.com/adriannovegil/awesome-observability
Supports
- Curated discovery of Vector, Grafana Loki, Graylog, and GoAccess
- https://vector.dev/docs/introduction/
Supports
- Vector as a pipeline for collecting, transforming, and routing logs
- https://grafana.com/docs/loki/latest/
Supports
- Loki's log aggregation, label model, query path, and beginner starting options
- https://go2docs.graylog.org/current/what_is_graylog/what_is_graylog.htm
Supports
- Graylog collection, parsing, enrichment, search, dashboards, and alerting
- https://goaccess.io/get-started
Supports
- GoAccess terminal, static HTML, and real-time HTML analysis of web access logs