Book Image

Docker for Developers

By : Richard Bullington-McGuire, Andrew K. Dennis, Michael Schwartz
2 (1)
Book Image

Docker for Developers

2 (1)
By: Richard Bullington-McGuire, Andrew K. Dennis, Michael Schwartz

Overview of this book

Docker is the de facto standard for containerizing apps, and with an increasing number of software projects migrating to containers, it is crucial for engineers and DevOps teams to understand how to build, deploy, and secure Docker environments effectively. Docker for Developers will help you understand Docker containers from scratch while taking you through best practices and showing you how to address security concerns. Starting with an introduction to Docker, you’ll learn how to use containers and VirtualBox for development. You’ll explore how containers work and develop projects within them after you’ve explored different ways to deploy and run containers. The book will also show you how to use Docker containers in production in both single-host set-ups and in clusters and deploy them using Jenkins, Kubernetes, and Spinnaker. As you advance, you’ll get to grips with monitoring, securing, and scaling Docker using tools such as Prometheus and Grafana. Later, you’ll be able to deploy Docker containers to a variety of environments, including the cloud-native Amazon Elastic Kubernetes Service (Amazon EKS), before finally delving into Docker security concepts and best practices. By the end of the Docker book, you’ll be able to not only work in a container-driven environment confidently but also use Docker for both new and existing projects.
Table of Contents (21 chapters)
1
Section 1: An Introduction to Docker – Containers and Local Development
6
Section 2: Running Docker in Production
14
Section 3: Docker Security – Securing Your Containers

Using labels for metadata application

Metadata labels are a way of annotating your containers with extra information to provide development teams with useful facts. This can be useful for other developers on your team when they need to understand key features of the image, such as its version and a description.

We saw with the docker secrets command how we could add labels via the command line. With metadata labels, we can also add labels to the Dockerfile so that when we build out a new container, this information is baked in.

A label takes the following format:

LABEL key=value

Building upon our preceding example, we can set the version inside of our container via the Dockerfile as follows:

LABEL "version"="1.1.2-test"
LABEL "description"=" Development environment container for testing the newest security patch. Not for production release yet"

Once you've built out a container, you can view any of the metadata you have...