The idea behind Docker is simple. Create a tiny virtual environment called a container that holds just your application and its dependencies. The Docker engine uses the host operating system to keep track of your containers. Applications running inside containers share resources, making their footprints small. They are easy to install, manage, and remove. Docker in Action, Second Edition teaches you to create, deploy, and manage applications hosted in Docker containers running on Linux. Fully updated, with four new chapters and revised best practices and examples, this second edition begins with a clear explanation of the Docker model. Then, you go hands-on with packaging applications, testing, installing, running programs securely, and deploying them across a cluster of hosts. With examples showing how Docker benefits the whole dev lifecycle, you'll discover techniques for everything from dev-and-test machines to full-scale cloud deployments.