Book Image

Getting Started with Containerization

By : Dr. Gabriel N. Schenker, Hideto Saito, Hui-Chuan Chloe Lee, Ke-Jou Carol Hsu
Book Image

Getting Started with Containerization

By: Dr. Gabriel N. Schenker, Hideto Saito, Hui-Chuan Chloe Lee, Ke-Jou Carol Hsu

Overview of this book

Kubernetes is an open source orchestration platform for managing containers in a cluster environment. This Learning Path introduces you to the world of containerization, in addition to providing you with an overview of Docker fundamentals. As you progress, you will be able to understand how Kubernetes works with containers. Starting with creating Kubernetes clusters and running applications with proper authentication and authorization, you'll learn how to create high-availability Kubernetes clusters on Amazon Web Services (AWS), and also learn how to use kubeconfig to manage different clusters. Whether it is learning about Docker containers and Docker Compose, or building a continuous delivery pipeline for your application, this Learning Path will equip you with all the right tools and techniques to get started with containerization. By the end of this Learning Path, you will have gained hands-on experience of working with Docker containers and orchestrators, including SwarmKit and Kubernetes. This Learning Path includes content from the following Packt products: • Kubernetes Cookbook - Second Edition by Hideto Saito, Hui-Chuan Chloe Lee, and Ke-Jou Carol Hsu • Learn Docker - Fundamentals of Docker 18.x by Gabriel N. Schenker
Table of Contents (25 chapters)
Title Page
Copyright
About Packt
Contributors
Preface
Index

Sharing or shipping images


To be able to ship our custom image to other environments, we need to first give it a globally unique name. This action is often called tagging an image. We then need to publish the image to a central location from which other interested or entitled parties can pull it. These central locations are called image registries.

Tagging an image

Each image has a so-called tag. A tag is often used to version images, but it has a broader reach than just being a version number. If we do not explicitly specify a tag when working with images, then Docker automatically assumes we're referring to the latest tag. This is relevant when pulling an image from Docker Hub, for example:

$ docker image pull alpine

The preceding command will pull the alpine:latest image from the Hub. If we want to explicitly specify a tag, we do so like this:

$ docker image pull alpine:3.5

This will now pull the alpine image that has been tagged with 3.5.

Image namespaces

So far, you have been pulling various...