This document provides an overview of Apache Flume, a distributed, reliable, and available service for efficiently collecting, aggregating, and moving large amounts of log data from many different sources to a centralized data store. It describes the core concepts in Flume including events, clients, agents, sources, channels, and sinks. Sources are components that read data and pass it to channels. Channels buffer events and sinks remove events from channels and transmit them to their destination. The document discusses commonly used source, channel and sink types and provides examples of Flume flows.