Dockerfiles

As we have seen, we can execute individual commands from the Shell. Docker provides a decent method to invoke several commands and instructs the new container to perform a specific job.

Dockerfiles is a script based on different Docker commands. Each command contains an instruction, and it configures the new machine step by step. It can contain all the information from pulling a repository to starting any server.

They have a clean and simple syntax that makes a file more readable and clear. It is designed to be self-explanatory and allows commenting like other programming languages.

Here is an example of a file syntax:

# Comments
command argument argument …
# To echo Hello World
RUN echo "Hello World"

Let's create a basic Dockerfile and use the same example of Hello World as follows:

1. Add the following content to Dockerfile:

   # Dockerfile
   FROM ubuntu
   RUN echo "Hello World"

2. Build the Docker container with the following command:

   $ sudo docker build -t local/test_docker
   

3. Our new container...