Telegraf is an open-source agent written in Go that collects, processes, and writes metrics, logs, and other data. It features over 300 plugins covering system monitoring, cloud services, messaging, and more. The tool compiles to a standalone binary, uses TOML configuration, and supports various data sources including Docker, Prometheus, Kafka, and system resources. With contributions from over 1,200 community members, it provides comprehensive monitoring capabilities for infrastructure and applications.