Containerizing web apps using Docker

Docker, which can be found at https://docker.io, is an open platform for developing, shipping, and running applications. Docker combines a lightweight container virtualization platform with workflows and tooling that help manage and deploy applications. The most obvious difference between Virtual Machines (VMs) and Docker containers is that VMs are usually dozens of gigabytes in size and require gigabytes of memory, whereas containers take up megabytes in terms of disk and memory size requirements. Furthermore, the Docker platform abstracts away host Operating System (OS)-level configuration settings, so every piece of configuration that is needed to successfully run an application is encoded within a human-readable format.

Anatomy of a Dockerfile

A Dockerfile consists of four main parts:

• FROM – where we can inherit from Docker’s minimal “scratch” image or a pre-existing image
• SETUP –...