How to install Docker and use it ?

STEP 1: Install Docker Desktop (Free)

1. Go to https://www.docker.com/products/docker-desktop/

   

2. Click “Download for Windows”.

3. Run the downloaded file → follow installer steps → keep default settings.

4. Restart your computer if asked.

5. Open Docker Desktop → wait till it says “Docker is running”.

   

6. Check in Command Prompt:

   docker --version

   

   
   

   If it shows a version, Docker is ready.

   
   

🧱STEP 2: Pull and Run a Container

Now let’s run some ready-made containers.

1. Open Command Prompt or PowerShell.

2. Run this:

   docker run hello-world

   This tests your Docker setup. If you see “Hello from Docker!”, everything works fine.

   

3. Run a small web server:

   docker run -d -p 8080:80 nginx

   
   

   -d → run in background

   -p 8080:80 → open it on port 8080

   
   

4. Open your browser → go to http://localhost:8080

   
   

5. You’ll see the NGINX welcome page.

   
   

STEP 3: Create Your Own Simple Docker App

Let’s make a small Python app and put it in a Docker image.

Step 3.1 — Create folder

Create a folder anywhere, like:

C:\docker-flask-app

Open Notepad, paste the following, and save as app.py inside that folder:

from flask import Flask
app = Flask(__name__)

@app.route('/')
def home():
    return "Hello from my first Docker app!"

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)

Also create a file named requirements.txt in the same folder:

flask

Now create another file named Dockerfile (no extension):

FROM python:3.10
WORKDIR /app
COPY . /app
RUN pip install -r requirements.txt
EXPOSE 5000
CMD ["python", "app.py"]

Step 3.2 — Build your Docker image

Open Command Prompt inside your folder (Shift + Right Click → “Open PowerShell window here”)

Run:

docker build -t myflaskapp .

Wait for it to finish.

Step 3.3 — Run your container

docker run -d -p 5000:5000 myflaskapp

Now open your browser → visit👉 http://localhost:5000

You’ll see:“Hello from my first Docker app!”

That’s it!

You have done:

1. Installed Docker

2. Pulled and ran containers

3. Created your own custom image