is an open-source log collector system written in C and Ruby. As a unified log collection and delivery engine, Fluentd can be integrated, via community-built input/output plugins, with a variety of log producers (e.g., Apache
, syslog, third-party applications) and log consumers (e.g., Nagios
for alerts, Elasticsearch for searching, Hadoop and MongoDB
for analytics, Amazon S3 for archiving). Internally, collected logs are converted into structured JSON data for downstream processing such as filtering and buffering. Fluentd supports a high availability deployment option, where multiple Fluentd instances operate either as a log forwarder (which collects event logs from a local node) or as a log aggregator (which buffers or processes collected logs). Fluentd comes with web-based management UI for managing plugins and collection processes.