#elk

Build centralized logging with ELK stack (Elasticsearch, Logstash, Kibana). Pipeline: 1. Filebeat agents on application servers. 2. Logstash for log parsing and enrichment. 3. Elasticsearch cluster for storage and indexing. 4. Kibana for visualization and search. 5. Index lifecycle management for retention. 6. Alerting on error patterns. 7. Log correlation across services. Use structured logging (JSON). Include security (authentication, encryption) and performance tuning (sharding, replicas).