Docker containers are a powerful tool for building and deploying services consistently and reliably. As the number of containers increases, they also become a problem to manage. The problem is only exasperated when the containers are run on multiple hosts. This book shows you how to get started bringing order to the chaos through orchestration.
This book starts by showing you how to get started with Docker then delves into the building blocks that are needed for a Docker cluster. It shows you how to use the "Big Three" orchestration tools—Docker Swarm, Kubernetes, and Mesosphere. It will also introduce two additional tools, Fleet and Cattle, which can be simpler to use and install, but very powerful.
Finally, you will be introduced to tools that make life simpler for people managing clusters and developers creating images that will be run. You will explore tools to monitor clusters and see where the performance bottlenecks are. You will see how to use continuous integration to consistently and reliably build, test, and deploy Docker images. Finally, this book will show you how to apply the same principles to the hosts that Docker is running on.
Chapter 1, Getting Started with Docker Orchestration , gets you started with using Docker. It shows you how to install Docker locally and on popular cloud services such as Amazon Web Services, Google Compute Engine, and Microsoft Azure.
Chapter 2, Building Multi-Container Applications with Docker Compose , provides an introduction to building multi-container applications with Docker Compose. It also shows how to use named networks for data isolation and data volumes to share data.
Chapter 3 , Cluster Building Blocks – Registry, Overlay Networks, and Shared Storage , describes the building blocks that are needed for a Docker cluster. You will explore the registry, overlay networks, and shared storage and learn why they are needed.
Chapter 4 , Orchestration with Docker Swarm , shows you how to create and manage a cluster with Docker Swarm. You will learn how to manage services, run them with multiple replicas, and perform "zero downtime" upgrades.
Chapter 5 , Deploying and Managing Services with Kubernetes , explores the basics of using Kubernetes to orchestrate a Docker cluster. You will see how to create services provided by multiple containers, how to provide load balancing for those services, and how to seamlessly upgrade them. Finally, you will see how to create persistent volumes to share data between containers.
Chapter 6 , Working with Mesosphere , delves into using Mesosphere and DC/OS for orchestration. You will learn how to create and manage containers, load-balance them, and provide persistent storage. You will also see how to create health checks to ensure that services are running properly and how to perform "zero downtime" upgrades.
Chapter 7 , Using Simpler Orchestration Tools – Fleet and Cattle, takes a look Fleet and Cattle. Fleet is a low-level tool that can be used to base custom management tools on. Cattle is a powerful, but easy to use, orchestration tool from Rancher. You will see how to use each to manage containers and services.
Chapter 8 , Monitoring Your Cluster , explores the important task of ensuring that clusters, and containers running in them, are behaving properly. You will learn how to aggregate logs from all your containers in Elasticsearch and view them in Kibana. You will also learn how to use collectd, InfluxDB, and Grafana to collect performance data.
Chapter 9 , Using Continuous Integration to Build, Test, and Deploy Containers , explains how to use continuous integration in GitLab to build, test, and even deploy containers. This helps to ensure that images are built consistently and reliably.
Chapter 10 , Why Stop at Containers? Automating Your Infrastructure , looks beyond containers to show how the same principles that go into building and orchestrating Docker containers can also be used with the hosts those containers run on. You will see how configuration management can be used to configure hosts and ensure that they stay configured. The chapter also shows you how to use Packer to build host images that can be deployed locally or to cloud services. Finally, it will introduce Terraform, which can be used to create an entire Docker cluster from scratch.
You will need a place to run Docker hosts. This can be in a local cluster such as OpenStack or a cloud hosting provider such as Amazon EC2, Google Compute Engine, or Microsoft Azure. The first chapter shows you how to install Docker on Linux and the rest of the book assumes that the tools are run from Linux. Ubuntu, CentOS, and Red Hat Enterprise Linux are, currently, the best supported.
A text editor, such as Emacs, will be needed as most orchestration tools store their configurations in text files. Many of the tools and examples described within this book require a web browser to access.
This book is for developers and system administrators who have a basic knowledge of Docker and now want to deploy and manage containers across multiple hosts.
In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.
Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "Containers are started using
docker run command."
A block of code is set as follows:
#cloud-config users: - name: "demo" passwd: "$6$HpqJOCs8XahT$mSgRYAn..." groups: - "sudo" - "docker"
When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:
- name: "demo"
Any command-line input or output is written as follows:
$ wget -qO - https://get.docker.com/ | sh
New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Select your account then click Allow on the next page."
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