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The Practical Guide to Running Docker on Linux Systems or Cloud Environments


Whether on your laptop or a remote cloud, Docker can transform how you create, test, deploy, and manage your most critical applications. In Docker Containers, Christopher Negus helps you master Docker containerization from the ground up.

You'll start out running a few Docker container images in Ubuntu, Fedora, RHEL, CoreOS, or Project Atomic. By the time you've finished, you'll be deploying enterprise-quality, multi-container Kubernetes setups in modern Linux and cloud environments.

Writing for system administrators, software developers, and technology enthusiasts, Negus touches on every aspect of working with Docker: setting up containerized applications, working with both individual and multiple containers, running containers in cloud environments, and developing containers.

Teaching through realistic examples of desktop applications, system services, and games, Negus guides you through building and deploying your own Dockerized applications. As you build your expertise, you'll also learn indispensable Docker best practices for building and integrating containers, managing Docker on a day-to-day basis, and much more:

 Understanding what Docker is and what you can do with it
 Installing Docker on standard Linux or specialized container operating systems such as Atomic Host and CoreOS
 Setting up a container runtime environment and private Docker Registry
 Creating, running, and investigating Docker images and containers
 Finding, pulling, saving, loading, and tagging container images
 Pulling and pushing containers between local systems and Docker Registries
 Integrating Docker containers with host networking and storage
 Building containers with the docker build command and Dockerfile files
 Minimizing space consumption and erasing unneeded containers
 Accessing special host privileges from within a container
 Orchestrating multiple containers into complex applications with Kubernetes
 Using super privileged containers in cloud environments
 Managing containers in the cloud with Cockpit
 Getting started with Docker container development
 Learning container build techniques from shared Dockerfiles

This book is part of the Pearson Content Update Program. As the technology changes, sections of this book will be updated or new sections will be added. The updates will be delivered to you via a free Web Edition of this book, which can be accessed with any Internet connection.



Preface xv
Acknowledgments xxi
About the Author xxiii


Part I: Getting Going with Containers 1


Chapter 1: Containerizing Applications with Docker 3
Understanding Pros and Cons of Containerizing Applications 4
...An Application Running Directly on a Host Computer 4
...An Application Running Directly within a Virtual Machine 5
Understanding the Upside of Containers 5
Understanding Challenges of Containerizing Applications 7
Understanding What Makes Up Docker 8
The Docker Project 8
The Docker Hub Registry 9
Docker Images and Containers 10
The docker Command 11
Approaching Containers 13
Summary 14


Chapter 2: Setting Up a Container Run-Time Environment 17
Configuring a Standard Linux System for Docker 18
Configuring Ubuntu for Docker 18
Configuring Fedora for Docker 21
Configuring Red Hat Enterprise Linux for Docker 25
Configuring Other Operating Systems for Docker 27
Configuring a Container-Style Linux System for Docker 29
Configuring an Atomic Host for Docker 29
Configuring CoreOS for Docker 32
Summary 34


Chapter 3: Setting Up a Private Docker Registry 35
Getting and Starting a Private Docker Registry 36
Setting Up a Docker Registry in Fedora 37
Setting Up a Docker Registry in Ubuntu 40
Configuring a Private Docker Registry 43
Configuring the docker-registry Package 43
Configuring the registry Container 46
Understanding the Docker Image Namespace 46
Summary 48


Part II: Working with Individual Containers 49


Chapter 4: Running Container Images 51
Running Container Images Interactively 54
Starting an Interactive Bash Shell 54
Playing Some Character-Based Games 56
Running Administrative Commands Inside a Container 57
Running Containerized Services 59
Running a Containerized Web Server 59
Limiting Resources When Running Services in Containers 62
Running Privileged Containers 63
Summary 64


Chapter 5: Finding, Pulling, Saving, and Loading Container Images 65
Searching for Images 66
Searching for Images with the docker Command 66
Searching for Images on Docker Hub 69
Searching Other Repositories for Images 70
Pulling Images from Registries 73
Saving and Loading Images 76
Summary 77


Chapter 6: Tagging Images 79
Assigning Names to Images 80
Assigning Tags to Images 81
Assigning Repository Names to Images 83
Attaching a User Name to an Image 83
Attaching a Repository Name to an Image 85
Summary 86


Chapter 7: Investigating Containers 87
Inspecting Images and Containers 88
Inspecting an Image 88
Inspecting Base Images with docker inspect 89
Inspecting Application Images with docker inspect 90
Looking at the History of an Image 92
Inspecting Running Containers 92
Start a Container to Inspect 93
Inspect an Entire Container Configuration 94
Inspect Individual Container Attributes 99
Finding More Ways to Look into Containers 103
Using docker top to See Container Processes 103
Using docker attach to Interact with a Service Inside a Container 104
Using docker exec to Start a New Process in a Running Container 105
Using docker logs to See Container Process Output 106
Using docker diff to See How a Container Has Changed 106
Using docker cp to Copy Files from a Container 107
Summary 107


Chapter 8: Starting, Stopping, and Restarting Containers 109
Stopping and Starting a Container 109
Stopping and Starting a Detached Container 110
Starting and Stopping an Interactive Container 112
Restarting a Container 113
Sending Signals to a Container 114
Pausing and Unpausing Containers 115
Waiting for a Container's Exit Code 116
Renaming a Container 117
Creating a Container 117
Summary 118


Chapter 9: Configuring Container Storage 121
Managing Storage for a Container 122
Using Volumes from the Host 122
Data Volume Container 123
Write-Protecting a Bind Mount 124
Mounting Devices 125
Mounting Sockets 125
Storage Strategies for the Docker Host 127
Attaching External Storage to a Docker Host 128
Summary 130


Chapter 10: Configuring Container Networking 133
Expose Ports to Other Containers 134
Map Ports Outside the Host 136
Map a Port from Linked Containers 136
Connect Containers on Different Hosts 138
Alternatives to the docker0 Bridge 139
Changing Network Mode for a Container 140
Examining Network Options 140
Changing the Docker Network Bridge 142
Summary 143


Chapter 11: Cleaning Up Containers 145
Making Space for Images and Containers 146
Removing Im