Book Image

Learn Docker - Fundamentals of Docker 19.x - Second Edition

By : Dr. Gabriel N. Schenker
Book Image

Learn Docker - Fundamentals of Docker 19.x - Second Edition

By: Dr. Gabriel N. Schenker

Overview of this book

Containers enable you to package an application with all the components it needs, such as libraries and other dependencies, and ship it as one package. Docker containers have revolutionized the software supply chain in both small and large enterprises. Starting with an introduction to Docker fundamentals and setting up an environment to work with it, you’ll delve into concepts such as Docker containers, Docker images, and Docker Compose. As you progress, the book will help you explore deployment, orchestration, networking, and security. Finally, you’ll get to grips with Docker functionalities on public clouds such as Amazon Web Services (AWS), Azure, and Google Cloud Platform (GCP), and learn about Docker Enterprise Edition features. Additionally, you’ll also discover the benefits of increased security with the use of containers. By the end of this Docker book, you’ll be able to build, ship, and run a containerized, highly distributed application on Docker Swarm or Kubernetes, running on-premises or in the cloud.
Table of Contents (25 chapters)
1
Section 1: Motivation and Getting Started
4
Section 2: Containerization, from Beginner to Black Belt
11
Section 3: Orchestration Fundamentals and Docker Swarm
18
Section 4: Docker, Kubernetes, and the Cloud

Storing configuration data in the swarm

If we want to store non-sensitive data such as configuration files in Docker Swarm, then we can use Docker configs. Docker configs are very similar to Docker secrets, which we will discuss in the next section. The main difference is that config values are not encrypted at rest, while secrets are. Docker configs can only be used in Docker Swarm, that is, they cannot be used in your non-Swarm development environment. Docker configs are mounted directly into the container's filesystem. Configuration values can either be strings or binary values up to a size of 500 KB.

With the use of Docker configs, you can separate the configuration from Docker images and containers. This way, your services can easily be configured with environment-specific values. The production swarm environment has different configuration values than the staging swarm...