The Docker images are the fundamental building blocks of containers. These images could be very basic operating environments, such as busybox or ubuntu, as we found while experimenting with Docker in the previous chapters. Alternatively, the images could craft advanced application stacks for the enterprise and cloud IT environments. As we discussed in the previous chapter, we could craft an image manually by launching a container from a base image, install all the required applications, make the necessary configuration file changes, and then commit the container as an image.

As a better alternative, we could resort to the automated approach of crafting the images by using Dockerfile. Dockerfile is a text-based build script that contains special instructions in a sequence for building the right and relevant images from the base images. The sequential instructions inside the Dockerfile can include the base image selection, installing the required application...