Book Image

Learning Docker - Second Edition

By : Vinod Singh, Pethuru Raj, Jeeva S. Chelladhurai
Book Image

Learning Docker - Second Edition

By: Vinod Singh, Pethuru Raj, Jeeva S. Chelladhurai

Overview of this book

Docker is an open source containerization engine that offers a simple and faster way for developing and running software. Docker containers wrap software in a complete filesystem that contains everything it needs to run, enabling any application to be run anywhere – this flexibily and portabily means that you can run apps in the cloud, on virtual machines, or on dedicated servers. This book will give you a tour of the new features of Docker and help you get started with Docker by building and deploying a simple application. It will walk you through the commands required to manage Docker images and containers. You’ll be shown how to download new images, run containers, list the containers running on the Docker host, and kill them. You’ll learn how to leverage Docker’s volumes feature to share data between the Docker host and its containers – this data management feature is also useful for persistent data. This book also covers how to orchestrate containers using Docker compose, debug containers, and secure containers using the AppArmor and SELinux security modules.
Table of Contents (13 chapters)

Sharing host data

Earlier, we described the steps to create a data volume in a Docker image using the VOLUME instruction in the Dockerfile. However, Docker does not provide any mechanism to mount the host directory or file during the build time in order to ensure the Docker images to be portable. The only provision Docker provides is to mount the host directory or file to a container's data volume during the container's launch. Docker exposes the host directory or file mounting facility through the -v option of the docker run subcommand. The -v option has five different formats, enumerated as follows:

  • -v <container mount path>
  • -v <host path>:<container mount path>
  • -v <host path>:<container mount path>:<read write mode>
  • -v <volume name>:<container mount path>
  • -v <volume name>:<container mount path>:<read write mode>

The <host path&gt...