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

Running pods

Kubernetes organizes containers into pods. Each pod is a collection of one or more containers. A pod can be replicated, scaled, and updated independently of other pods running in the cluster. Each pod is assigned an IP address, which is used to connect to the exposed ports of containers running in the pod. Care must be taken to ensure that services within a pod do not try to use the same port, but that is much easier to coordinate than managing port usage across a Docker Swarm.

Defining a pod

Pods define one or more containers as well as all of the volumes that the containers need. The containers operate as a single unit. They are all started and stopped together. They can also communicate with each other on localhost. The pod is defined using YAML or JSON and passed to kubectl create. Following is a simple pod definition:

apiVersion: v1 
kind: Pod 
  name: simple 
    - name: web 
      image: nginx