Containers are everywhere! Since the release of Docker in 2013, containers have found their way into many aspects of software. We use them for packaging, distribution, deployment and running our software. They enable more efficient local development. They power our continuous integration/deployment systems. There are even entire large orchestration platforms built around containers to facilitate securely running your software at scale. It's fair to say, containers are a vital part of the modern software world. Many developers write a docker file (or copy and paste one), use docker to build an image, and push off the results. But what is a container really? What is an image? What is the magic behind this technology? In this talk, we're going to deep dive into containers, images and the surrounding technology. We'll explore the fundamental technologies that make containers possible: namespaces, cgroups, and union filesystems. You'll learn how containers provide a level of isolation, how images are constructed layer by layer, and the underlying mechanics that make containers both secure and powerful. Whether you're a developer looking to better understand the tools you use daily or an operations professional seeking deeper insights, this talk will take you under the hood of container technology.