Create a Dockerfile for the New Custom Image

The first step when building a customized image is to create a Dockerfile that specifies which packages you would like to install in addition to the base image.

For example, the following Dockerfile installs the beautifulsoup4 package on top of the base Ubuntu image that ships with Cloudera Data Science Workbench.
# Dockerfile

# Specify a Cloudera Data Science Workbench base image
FROM docker.repository.cloudera.com/cdsw/engine:8

# Update packages on the base image and install beautifulsoup4
RUN apt-get update
RUN pip install beautifulsoup4 && pip3 install beautifulsoup4