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.
Table of Contents (13 chapters)

Docker inbuilt service discovery

The Docker platform inherently supports the service discovery for the containers that are attached to any user-defined network using an embedded Domain Name Service (DNS). This functionality has been added to Docker since the version 1.10. The embedded DNS feature enables the Docker containers to discover each other using their names or aliases within the user-defined network. In other words, the name resolution request from the container is first sent to the embedded DNS. The user-defined network then uses a special 127.0.0.11 IP address for the embedded DNS, which is also listed in /etc/resolv.conf.

The following example will help to gain a better understanding of Docker's built-in service discovery capability:

  1. Let's begin by creating a user-defined bridge network, mybridge, using the following command:
      $ sudo docker network create mybridge
  1. Inspect the newly...