Book Image

Learn Docker - Fundamentals of Docker 18.x

By : Dr. Gabriel N. Schenker
Book Image

Learn Docker - Fundamentals of Docker 18.x

By: Dr. Gabriel N. Schenker

Overview of this book

Docker containers have revolutionized the software supply chain in small and big enterprises. Never before has a new technology so rapidly penetrated the top 500 enterprises worldwide. Companies that embrace containers and containerize their traditional mission-critical applications have reported savings of at least 50% in total maintenance cost and a reduction of 90% (or more) of the time required to deploy new versions of those applications. Furthermore they are benefitting from increased security just by using containers as opposed to running applications outside containers. This book starts from scratch, introducing you to Docker fundamentals and setting up an environment to work with it. Then we delve into concepts such as Docker containers, Docker images, Docker Compose, and so on. We will also cover the concepts of deployment, orchestration, networking, and security. Furthermore, we explain Docker functionalities on public clouds such as AWS. By the end of this book, you will have hands-on experience working with Docker containers and orchestrators such as SwarmKit and Kubernetes.
Table of Contents (21 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Anatomy of containers


Many individuals wrongly compare containers to VMs. However, this is a questionable comparison. Containers are not just lightweight VMs. OK then, what is the correct description of a container?

Containers are specially encapsulated and secured processes running on the host system.

Containers leverage a lot of features and primitives available in the Linux OS. The most important ones are namespaces and cgroups. All processes running in containers share the same Linux kernel of the underlying host operating system. This is fundamentally different compared with VMs, as each VM contains its own full-blown operating system.

The startup times of a typical container can be measured in milliseconds, while a VM normally needs several seconds to minutes to startup. VMs are meant to be long-living. It is a primary goal of each operations engineer to maximize the uptime of their VMs. Contrary to that, containers are meant to be ephemeral. They come and go in a quick cadence.

Let's...