Gain insights into working with Docker containers, discover common pitfalls, and explore best practices to efficiently build modern applications, regardless of your experience level.

A Guide For Building Modern Applications With Docker_ .png

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This course simplifies working with Docker containers (whether you're a novice or an intermediate engineer) and also exposes some common pitfalls. We’ve also added some best practices that might be useful while working with Docker.

Simple Steps to Building Modern Applications with Docker

There are two ways to create Docker images:

1. We can create a Docker image by automatically building the image following the instructions in a text file called a Dockerfile.
2. We can create a Docker image by modifying a running container content and committing the changes. It’s like taking a snapshot of a running container.

Making changes to a running container and committing the change to create a new image works well for some use cases. However, it’s more practical and effortlessly reproducible to use a Dockerfile.

Before we get started with a Dockerfile and creating a Docker image using the `docker build` command, let’s first define a Dockerfile.


# Dockerfile 
A **Dockerfile** is a text file that contains step-by-step instructions for Docker to build an image. When we run a `docker build` command while specifying a Dockerfile, Docker creates an image based on the instructions in the Dockerfile.

Just as a Docker image is immutable, so are the images created from Dockerfiles. The same Dockerfile will always produce the same Docker image as long as the instructions in the Dokerfile and the container dependencies don’t change.




# Common Dockerfile commands 

A Dockerfile must, at the very least, include the `FROM`, `COPY`, and `CMD`. commands. Commands are the building blocks of a Dockerfile. They enable us to write fully-fledged Dockerfiles.

Let’s look at some common commands we’ll use in our day-to-day work.

## `FROM`

`FROM `usually starts from the beginning of a Dockerfile. It specifies the starting point for building an image. Most Docker images we build will start from a base image called the parent image. The `FROM` command specifies the exact base image to Docker. We can use `FROM` in Dockerfiles in the following way:


Understand common Dockerfile instructions and how to combine them to write a Dockerfile.

Introduction to the Course

Getting Started with Docker

A Guide to Building Docker Images

Working with Multiple Docker Containers

Working With Docker in CI Environments

Staying secure

Conclusion

What’s a Dockerfile?

Dockerfile

Common Dockerfile commands