Book Image

Learning Docker - Second Edition

By : Vinod Singh, Pethuru Raj, Jeeva S. Chelladhurai

Book Image

Learning Docker - Second Edition

By: Vinod Singh, Pethuru Raj, Jeeva S. Chelladhurai

Overview of this book

Docker is an open source containerization engine that offers a simple and faster way for developing and running software. Docker containers wrap software in a complete filesystem that contains everything it needs to run, enabling any application to be run anywhere – this flexibily and portabily means that you can run apps in the cloud, on virtual machines, or on dedicated servers. This book will give you a tour of the new features of Docker and help you get started with Docker by building and deploying a simple application. It will walk you through the commands required to manage Docker images and containers. You’ll be shown how to download new images, run containers, list the containers running on the Docker host, and kill them. You’ll learn how to leverage Docker’s volumes feature to share data between the Docker host and its containers – this data management feature is also useful for persistent data. This book also covers how to orchestrate containers using Docker compose, debug containers, and secure containers using the AppArmor and SELinux security modules.

Preface

What this book covers

What you need for this book

Who this book is for

Reader feedback

Customer support

Free Chapter

Getting Started with Docker

Getting Started with Docker

The key drivers for Dockerization

Differentiating between containerization and virtualization

Installing the Docker Engine

Understanding the Docker setup

Downloading the first Docker image

Running the first Docker container

Handling Docker Containers

Handling Docker Containers

Clarifying Docker terms

Working with Docker images

Working with an interactive container

Building Images

Building Images

Docker's integrated image building system

A quick overview of the Dockerfile's syntax

The Dockerfile build instructions

A brief on the Docker image management

Best practices for writing a Dockerfile

Publishing Images

Publishing Images

Understanding Docker Hub

Pushing images to Docker Hub

Automating the build process for images

Private repositories on Docker Hub

Organizations and teams on Docker Hub

The REST API for Docker Hub

Running Your Private Docker Infrastructure

Running Your Private Docker Infrastructure

Docker Registry

Docker Registry use cases

Running Docker Registry and pushing the image

Running the Docker Registry on localhost with an SSL certificate

Running Docker Registry with restrictions

Managing Docker Registry with Docker Compose

Load balancing consideration

Webhook notifications

Docker Registry HTTP API support

Running Services in a Container

Running Services in a Container

A brief overview of container networking

Envisaging container as a service

Exposing container services

Sharing Data with Containers

Sharing Data with Containers

The volume management command

Sharing host data

Sharing data between containers

Avoiding common pitfalls

Orchestrating Containers

Orchestrating Containers

Docker inbuilt service discovery

Linking containers

Orchestration of containers

Testing with Docker

Testing with Docker

A brief overview of TDD

Testing your code inside Docker

Integrating Docker testing into Jenkins

Debugging Containers

Debugging Containers

Process-level isolation for Docker containers

The docker exec command

The docker ps command

The docker top command

The docker stats command

The Docker events command

The docker logs command

The docker attach command

Debugging a Dockerfile

Securing Docker Containers

Securing Docker Containers

The security scenario in the containerization domain

Immutable infrastructure

The best practices for container security

The Docker Platform – Distinct Capabilities and Use Cases

The Docker Platform – Distinct Capabilities and Use Cases

Describing containers

Briefing the Docker platform

Implications of the Docker technology

The Docker use cases

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Summary

In this chapter, you have seen the isolation of containers using the Linux container technology, such as LXC and now Libcontainer. Libcontainer is Docker's own implementation in the Go programming language to access the kernel namespace and cgroups. This namespace is used for process-level isolation, while cgroups are used for restricting the resource usage of running containers. Since the containers run as independent processes directly over the Linux kernel, the Generally Available (GA) debugging tools are not fit enough to work inside the containers to debug the containerized processes. Docker now provides you with a rich set of tools to effectively debug the container as well as processes inside the container itself. The docker exec command will allow you to log in to the container without running an SSH daemon in the container. You have seen the details of each debugging tool in this chapter.

The...