Book Image

The Docker Workshop

By : Vincent Sesto, Onur Yılmaz, Sathsara Sarathchandra, Aric Renzo, Engy Fouda
5 (3)
Book Image

The Docker Workshop

5 (3)
By: Vincent Sesto, Onur Yılmaz, Sathsara Sarathchandra, Aric Renzo, Engy Fouda

Overview of this book

No doubt Docker Containers are the future of highly-scalable software systems and have cost and runtime efficient supporting infrastructure. But learning it might look complex as it comes with many technicalities. This is where The Docker Workshop will help you. Through this workshop, you’ll quickly learn how to work with containers and Docker with the help of practical activities.? The workshop starts with Docker containers, enabling you to understand how it works. You’ll run third party Docker images and also create your own images using Dockerfiles and multi-stage Dockerfiles. Next, you’ll create environments for Docker images, and expedite your deployment and testing process with Continuous Integration. Moving ahead, you’ll tap into interesting topics and learn how to implement production-ready environments using Docker Swarm. You’ll also apply best practices to secure Docker images and to ensure that production environments are running at maximum capacity. Towards the end, you’ll gather skills to successfully move Docker from development to testing, and then into production. While doing so, you’ll learn how to troubleshoot issues, clear up resource bottlenecks and optimize the performance of services. By the end of this workshop, you’ll be able to utilize Docker containers in real-world use cases.
Table of Contents (17 chapters)
Preface

What Is a Dockerfile?

A Dockerfile is a text file that contains instructions on how to create a Docker image. These commands are known as directives. A Dockerfile is a mechanism that we use to create a custom Docker image as per our requirements.

The format of a Dockerfile is as follows:

# This is a comment
DIRECTIVE argument

A Dockerfile can contain multiple lines of comments and directives. These lines will be executed in order by the Docker Engine while building the Docker image. Like programming languages, a Dockerfile can also contain comments.

All statements starting with the # symbol will be treated as a comment. Currently, Dockerfiles only support single-line comments. If you wish you write a multi-line comment, you need to add the # symbol at the beginning of each line.

However, unlike most programming languages, instructions within the Dockerfile are not case-sensitive. Even though the DIRECTIVE is case-insensitive, it is a best practice to write all directives in uppercase to distinguish them from arguments.

In the next section, we will discuss the common directives that we can use in Dockerfiles to create a custom Docker image.

Note

If you are using ubuntu versions later than 18.04, there will be a prompt to enter time zone. Please suppress the prompt with ARG DEBIAN_FRONTEND=non_interactive