This document provides an overview of Apache Kafka including its main components, architecture, and ecosystem. It describes how LinkedIn used Kafka to solve their data pipeline problem by decoupling systems and allowing for horizontal scaling. The key elements of Kafka are producers that publish data to topics, the Kafka cluster that stores streams of records in a distributed, replicated commit log, and consumers that subscribe to topics. Kafka Connect and the Schema Registry are also introduced as part of the Kafka ecosystem.