DevOps: Puppet, Docker, and Kubernetes

Building images using Dockerfiles

Dockerfiles help us in automating image creation and getting precisely the same image every time we want it. The Docker builder reads instructions from a text file (a Dockerfile) and executes them one after the other in order. It can be compared as Vagrant files, which allows you to configure VMs in a predictable manner.

Getting ready

A Dockerfile with build instructions.

• Create an empty directory:

  $ mkdir sample_image
  $ cd sample_image
  

• Create a file named Dockerfile with the following content:

  $ cat Dockerfile
  # Pick up the base image 
  FROM fedora 
  # Add author name 
  MAINTAINER Neependra Khare 
  # Add the command to run at the start of container 
  CMD date
  

How to do it…

1. Run the following command inside the directory, ...