Before we begin, we need a Dockerfile with build instructions. To make one, we need to go through the following steps:

1. Create an empty directory:

       $ mkdir sample_image
       $ cd sample_image
  

2. Create a file named Dockerfile with the following content:

       $ cat Dockerfile
       # Use ubuntu as the base image 
       FROM ubuntu 
    
       # Add author's name 
       LABEL maintainer="Jeeva S. Chelladhurai" 
    
       # Add the command to run at the start of container 
       CMD date