Docker for Beginners: A Comprehensive Guide for Understanding and Using Docker

StepstoDevOps
5 min readMay 22, 2023

Tag : docker-for-beginners-comprehensive-guide

Confused about how to learn Docker ? Then just follow this Blog and Learn.

Are you new to Docker and looking to learn more about this open-source containerization platform? Look no further than this comprehensive guide for beginners. In this guide, we’ll cover everything you need to know about Docker, including what it is, what it’s used for, and how to get started.

Description : Learn all about Docker, an open-source containerization platform used for developing, deploying, and managing applications in lightweight virtualized environments called containers.

So , the 1st Question that comes in mind is -> What is Docker?

Docker is an open-source containerization platform used for developing, deploying, and managing applications in lightweight virtualized environments called containers. Containers are like lightweight virtual machines that provide an isolated environment for applications to run. Docker allows developers to separate their applications from the underlying infrastructure, making it easier to deliver software quickly.

credit — Red Hat for Image

Now the Question comes -> What can I use Docker for?

So , Docker simplifies application development and removes complexities for you and many other developers around the world. Docker is ideal for the following scenarios :
1) Developing and testing applications
2) Deploying applications in production environments
3) Running legacy applications on modern infrastructure
4) Building microservices-based architectures

So , Let’s understand this with a simple example :- Like you have a web application that requires a specific version of Python and some Python libraries. You can create a Docker image that includes the Python version and libraries required by your application. This image can then be used to create a Docker container that runs your web application. The container will have everything it needs to run the application, including the operating system, Python, and the required libraries. You can then deploy this container to any system that supports Docker, and it will run the same way as it did on your development machine.

So ,Docker works by packaging applications along with their dependencies into containers.

After this all , now the question comes how to get started -> One of the best ways to get started with Docker is by installing Docker Desktop — especially if you’re a developer using Mac or Windows. That said, you might be wondering, “What’s Docker Desktop, and how’s it different from the open-source Docker Engine?”

Docker Desktop is a complete solution for building, testing, and deploying containerized applications. It includes everything you need to get started with Docker, including the Docker Engine, a container runtime, and a graphical user interface (GUI) for managing containers.

So ,Let’s get started with Docker step-by-step :-

  1. Create a Python web application : You can use a web framework like Flask or Django to create a Python web application.

So , Create a folder with the name flask_app to contain your application then install Flask.

mkdir flask_app
cd flask_app
pip install Flask

2. Create a view.py file that will contains the Python code snippet below: Use the @app.route() decorator to define a route for your application. For example, you can define a route for the home page of your application using the following code:

from flask import Flask, render_template
import os
app = Flask(__name__)
@app.route('/')
def home():
return 'Hello, World!'
if __name__ == '__main__':
app.run()

3. Now , Start the application: Open your terminal and navigate to the directory where your Python file is located. Run the following command to start the application: python view.py

4. Test the application: Open your web browser and navigate to http://localhost:8000/. You should see a message that says "Hello, World!".

5. Now Dockerize this Application , Let’s create Dockerfile :

# start by pulling the python image
FROM python:3.8-alpine

# copy the files into the image
COPY ./view.py /app/view.py

# switch working directory
WORKDIR /app

# copy every content from the local file to the image
COPY . /app

# configure the container to run in an executed manner
ENTRYPOINT [ "python" ]

CMD ["view.py" ]

6. Let’s Discuss a bit about steps involved in the Dockerfile :

1st Define the base image: In the Dockerfile, define the base image that your application will run on. Like here, we are using the official Python image .

2nd Copy the application code: In the Dockerfile, copy the application code into the image using the COPY command.

3rd Install dependencies: In the Dockerfile, install any dependencies required by the application using the RUN command.

4th Expose the port: In the Dockerfile, expose the port on which the application will run using the EXPOSE command.

5th Set the command to run the application: In the Dockerfile, set the command to run the application using the CMD command.

7. Build the Docker image: Run the following command to build the Docker image from the Dockerfile: docker build -t <image-name> .

8. Run the Docker container: Run the following command to run the Docker container from the image: docker run -p <host-port>:<container-port> <image-name> Like->

docker run -p 8000:8000 -d <image-name>

9. Test the application: Open your web browser and navigate to http://localhost:<host-port>/. You should see a message that says "Hello, World!".

10. At-last Push the Docker Image to Docker Hub (Open Source Public Container Registry ) : Rename the image -

docker tag <image-name> <your-docker-hub-username>/<image-name>

The final step is to push the image to Docker Hub by using the following command:

docker push <your-docker-hub-username>/<image-name>

After creating a Docker Application this Question get’s cleared as — What are some benefits of using Docker ?
Here are some of the key benefits of using Docker :
- Portability : Containers can be easily moved between different environments without any changes.
- Consistency : Containers provide a consistent environment for running applications across different environments.
- Scalability : Containers can be easily scaled up or down depending on demand.
- Efficiency : Containers use fewer resources than traditional virtual machines.
- Security : Containers provide an additional layer of security by isolating applications from each other.

Conclusion :
In conclusion, if you’re looking for a way to simplify application development and deployment, look no further than Docker. With its ability to package applications along with their dependencies into containers, developers can separate their applications from the underlying infrastructure, making it easier to deliver software quickly.

By following this comprehensive guide and getting started with Docker Desktop, you’ll be well on your way to leveraging the power of Docker in your own development workflows.

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