Kafka: The Definitive Guide, 2nd Edition

Foreword to the First Edition

It’s an exciting time for Apache Kafka. Kafka is being used by tens of thousands of organizations, including over a third of the Fortune 500 companies. It’s among the fastest-growing open source projects and has spawned an immense ecosystem around it. It’s at the heart of a movement toward managing and processing streams of data.

So where did Kafka come from? Why did we build it? And what exactly is it?

Kafka got its start as an internal infrastructure system we built at LinkedIn. Our observation was really simple: there were lots of databases and other systems built to store data, but what was missing in our architecture was something that would help us to handle the continuous flow of data. Prior to building Kafka, we experimented with all kinds of off-the-shelf options, from messaging systems to log aggregation and ETL tools, but none of them gave us what we wanted.

We eventually decided to build something from scratch. Our idea was that instead of focusing on holding piles of data like our relational databases, key-value stores, search indexes, or caches, we would focus on treating data as a continually evolving and ever-growing stream and build a data system—and indeed a data architecture—oriented around that idea.

This idea turned out to be even more broadly applicable than we expected. Though Kafka got its start powering real-time applications and data flow behind the scenes of a social network, you can now see it at the heart of next-generation ...