Preface
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 costs and a reduction of 90% (or more) in deploying new versions of those applications. Furthermore, they are benefiting from increased security by using containers rather than 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, and Docker Compose. 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.
Who this book is for
This book is targeted at system administrators, operations engineers, DevOps engineers, and developers or stakeholders who are interested in getting started with Docker from scratch. No prior experience with Docker containers is required.
What this book covers
Chapter 1, What Are Containers and Why Should I Use Them?, focuses on the software supply chain and the friction within it. It then presents containers as a means to reduce this friction and add enterprise-grade security on top of it. In this chapter, we also look into how containers and the ecosystem around them are assembled. We specifically point out the distinction between the upstream OSS components (Moby) that form the building blocks of the downstream products of Docker and other vendors.
Chapter 2, Setting up a Working Environment, discusses in detail how to set up an ideal environment for developers, DevOps engineers, and operators that can be used when working with Docker containers.
Chapter 3, Working with Containers, teaches how start, stop, and remove containers. The chapter also teaches how to inspect containers to retrieve additional metadata. Furthermore, it introduces how to run additional processes and how to attach to the main process in an already running container. It also shows how to retrieve logging information from a container that is produced by the processes running inside it.
Chapter 4, Creating and Managing Container Images, introduces the different ways to create container images, which serve as templates for containers. It introduces the inner structure of an image and how it is built.
Chapter 5, Data Volumes and System Management, introduces data volumes that can be used by stateful components running in containers. The chapter also introduces system-level commands that are used to gather information about Docker and the underlying OS, as well as commands to clean the system from orphaned resources. Finally, it introduces the system events generated by the Docker engine.
Chapter 6, Distributed Application Architecture, introduces the concept of a distributed application architecture and discusses the various patterns and best practices that are required to run a distributed application successfully. Finally, it discusses the additional requirements that need to be fulfilled to run such an application in production.
Chapter 7, Single-Host Networking, introduces the Docker container networking model and its single-host implementation in the form of the bridge network. The chapter introduces the concept of software-defined networks (SDNs) and how they are used to secure containerized applications. Finally, it introduces how container ports can be opened to the public and thus how to make containerized components accessible from the outside world.
Chapter 8, Docker Compose, introduces the concept of an application consisting of multiple services, each running in a container, and how Docker Compose allows us to easily build, run, and scale such an application using a declarative approach.
Chapter 9, Orchestrators, introduces the concept of orchestrators. It teaches why orchestrators are needed and how they work. The chapter also provides an overview of the most popular orchestrators and explores a few of their pros and cons.
Chapter 10, Introduction to Docker Swarm, introduces Docker's native orchestrator called SwarmKit. It elaborates on all the concepts and objects SwarmKit uses to deploy and run a distributed, resilient, robust, and highly available application in a cluster on-premise, or in the cloud. The chapter also introduces how SwarmKit ensures secure applications using SDNs to isolate containers and secrets to protect sensitive information.
Chapter 11, Zero Downtime Deployments and Secrets, teaches how to deploy services or applications onto a Docker swarm with zero downtime and automatic rollback capabilities. It also introduces secrets as a means to protect sensitive information.
Chapter 12, Introduction to Kubernetes, introduces the currently most popular container orchestrator. It introduces the core Kubernetes objects that are used to define and run a distributed, resilient, robust, and highly available application in a cluster. Finally, it introduces Minikube as a way to locally deploy a Kubernetes application and also the integration of Kubernetes with Docker for Mac and Docker for Windows.
Chapter 13, Deploying, Updating, and Securing an Application with Kubernetes, teaches how to deploy, update, and scale applications into a Kubernetes cluster. It also explains how zero-downtime deployments are achieved to enable disruption free updates and rollbacks of mission-critical applications. This chapter also introduces Kubernetes secrets as a means to configure services and protect sensitive data.
Chapter 14, Running a Containerized App in the Cloud, gives an overview over some of the most popular ways of running containerized applications in the cloud. We have a closer look to what the most popular cloud vendor, AWS, offers in this regard. We include self-hosting and hosted solutions and discuss their pros and cons. Offerings of other vendors, such as Microsoft Azure and Google Cloud Engine, are also briefly discussed.
To get the most out of this book
Ideally you have access to a laptop or personal computer with Windows 10 Professional or a recent version of Mac OS X installed. A computer with any popular Linux OS installed works too. If you're on a Mac you should install Docker for Mac and if you're on Windows then install Docker for Windows. You can download them from here: https://www.docker.com/community-edition
If you are on an older version of Windows or are using Windows 10 Home edition, then you should install Docker Toolbox. You can find the Docker Toolbox here: https://docs.docker.com/toolbox/toolbox_install_windows/
On the Mac, use the Terminal application, and on Windows, use a PowerShell console to try out the commands you will be learning. You also need a recent version of a browser such as Google Chrome, Safari or Internet Explorer. Of course you will need internet access to download tools and container images that we are going to use and explore in this book.
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