Resources
---------

#. |Dockerfile tutorial by example - basics and best practices [2018]|
#. |Best practices for writing Dockerfiles|
#. |How To Build Your Own Docker Images|
#. |Gotchas in Writing Dockerfile|

.. |Best practices for writing Dockerfiles| raw:: html

   <a href="https://docs.docker.com/develop/develop-images/dockerfile_best-practices/" target="_blank">Best practices for writing Dockerfiles</a>

.. |Dockerfile tutorial by example - basics and best practices [2018]| raw:: html

   <a href="https://takacsmark.com/dockerfile-tutorial-by-example-dockerfile-best-practices-2018/"target=_blank">Dockerfile tutorial by example - basics and best practices [2018]</a>

.. |Gotchas in Writing Dockerfile| raw:: html

   <a href="https://kimh.github.io/blog/en/docker/gotchas-in-writing-dockerfile-en/" target="_blank">Gotchas in Writing Dockerfile</a>

.. |How To Build Your Own Docker Images| raw:: html

   <a href="https://blog.iron.io/how-to-build-your-own-docker-images/" target="_blank">How To Build Your Own Docker Images</a>


Dockerfile Elements
-------------------

This lab explains how to use ``dockerfile`` to create a docker image.
A dockerfile is a text file that contains the commands necessary to
create an image using the ``docker build`` command. A ``dockerfile``
uses these commands to build an image.

ADD
   Copy files from a source on the host to the containers own
   filesystem at the set destination.

CMD
   Execute a specific command within the container.

ENTRYPOINT
   Set a default application to be used every time a container is created
   with the image.

ENV
   Set environment variables.

EXPOSE
   Expose a specific port to enable networking between the container
   and the outside world.

FROM
   Define the base image used to start the build process.

MAINTAINER
   Define the full name and email address of the image creator.

RUN
   Central executing directive for Dockerfiles.

USER
   Set the UID (the username) that will run the container.

VOLUME
   Enable access from the container to a directory on the host machine.

WORKDIR
   Set the path where the command, defined with CMD, is to be executed.