Logging overview

Centralized log aggregation, indexing, and search for structured and unstructured log streams emitted by applications, infrastructure, and platform components. Core concerns include log shipping (Fluentd, Fluent Bit, Vector), retention policies, cardinality, and cost. Popular implementations: the ELK/EFK stack (Elasticsearch/OpenSearch + Logstash/Fluentd + Kibana), Grafana Loki (label-based log aggregation paired with Grafana dashboards), Splunk (enterprise), and managed offerings (AWS CloudWatch Logs, Datadog Logs, Papertrail). Structured JSON logging is preferred over plain text for machine-readable queries. Closely integrated with the Metrics and Tracing stack parts.