Book Image

Docker Orchestration

By : Randall Smith
Book Image

Docker Orchestration

By: Randall Smith

Overview of this book

Docker orchestration is what you need when transitioning from deploying containers individually on a single host to deploying complex multi-container apps on many machines. This book covers the new orchestration features of Docker 1.12 and helps you efficiently build, test, and deploy your application using Docker. You will be shown how to build multi-container applications using Docker Compose. You will also be introduced to the building blocks for multi-host Docker clusters such as registry, overlay networks, and shared storage using practical examples. This book gives an overview of core tools such as Docker Machine, Swarm, and Compose which will enhance your orchestration skills. You’ll learn how to set up a swarm using the decentralized building block. Next, you’ll be shown how to make the most out of the in-built orchestration feature of Docker engine and you’ll use third-party tools such as Kubernetes, Mesosphere, and CoreOS to orchestrate your existing process. Finally, you will learn to deploy cluster hosts on cloud services and automate your infrastructure.
Table of Contents (17 chapters)
Docker Orchestration
About the Author
About the Reviewer
Customer Feedback

Multi-container applications

The example in the previous section was fun but did not really gain us anything over using the docker command. Most Internet applications have multiple pieces. The most common example is a web application that loads data from a database.

In ch02/web-db of the docker-orchestration-examples repository there is a very simple application that loads a list of authors and books from MySQL and displays them on a web page. Here is a docker-compose.yml that defines the application:

version: '2' 
    image: web-db:0.1 
    build: . 
      - 80:5000 
      - db.env 
    entrypoint: ./ --init --command shotgun 
    image: mysql:5.7 
      - db.env 

The first thing that you should notice is that there are two services defined. The first, web, is the web application. The second, db, is a MySQL container. Let's look at them one...