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)

Process-level isolation for Docker containers

In the virtualization paradigm, the hypervisor emulates computing resources and provides a virtualized environment called a VM to install the operating system and applications on top of it. Whereas, in the case of the container paradigm, a single system (bare metal or VM) is effectively partitioned to run multiple services simultaneously without interfering with each other. These services must be isolated from each other in order to prevent them from stepping on each other's resources or dependency conflict (also known as dependency hell). The Docker container technology essentially achieves process-level isolation by leveraging the Linux kernel constructs, such as namespaces and cgroups, particularly, the namespaces. The Linux kernel provides the following five powerful namespace levers for isolating the global system resources from each other. These are the Interprocess...