🚀 Beginner Friendly Guide: Deploy a Python Flask App with Docker on EC2 & Push to Docker Hub

Hello everyone! 👋

Today, I’m sharing a simple, step-by-step hands-on guide to help you deploy a Python Flask app using Docker on an Amazon Linux EC2 instance — and then push your Docker image to Docker Hub.

---

🛠️ Why this tutorial?

• ✅ Get hands-on experience with Docker on AWS EC2

• ✅ Learn how to containerize a Python Flask app

• ✅ Push your image to Docker Hub for easy reuse

---

⚙️ Prerequisites

• AWS EC2 instance running Amazon Linux

• Docker installed

• Docker Hub account

• Basic SSH knowledge

---

🔐 Step 1: SSH into your EC2 instance

ssh -i your-key.pem ec2-user@your-ec2-public-ip

---

🐳 Step 2: Install Docker

sudo yum update -y
sudo yum install docker -y
sudo systemctl start docker
sudo systemctl enable docker
sudo usermod -aG docker ec2-user
newgrp docker
docker --version

📦 Step 3: Create Your Flask App

mkdir flask-docker-demo
cd flask-docker-demo
vi app.py

Paste the following code inside app.py:

from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello():
    return "Hello from Flask running in Docker on EC2!"

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

---

📄 Step 4: Add dependencies

vi requirements.txt

Add:

flask

---

🧱 Step 5: Create Dockerfile

vi Dockerfile

Paste:

FROM python:3.11-slim
WORKDIR /app
COPY . .
RUN pip install -r requirements.txt
EXPOSE 5000
CMD ["python", "app.py"]

---

📘 Dockerfile Explained (Simple Terms)

# Use official Python image
FROM python:3.11-slim

Starts with a lightweight Python 3.11 image as the base.

# Set working directory
WORKDIR /app

Sets the folder inside the container to /app where your code will live.

# Copy files
COPY . .

Copies all your local project files into the container’s /app folder.

# Install dependencies
RUN pip install -r requirements.txt

Installs the Python packages your app needs (like Flask).

# Expose port
EXPOSE 5000

Tells Docker your app will use port 5000 inside the container.

# Run the app
CMD ["python", "app.py"]

Runs your Flask app when the container starts.

In short:
This Dockerfile builds a Python image, copies your app code, installs Flask, and runs your server on port 5000.

---

🔨 Step 6: Build the Docker Image

docker build -t flask-app .

---

🚀 Step 7: Run Your Flask App

docker run -d -p 5000:5000 flask-app

Now open your browser:

http://<your-ec2-public-ip>:5000

You should see:

Hello from Flask running in Docker on EC2!

---

☁️ Step 8: Push Your Image to Docker Hub

1️⃣ Login to Docker Hub

docker login

Enter your Docker Hub credentials (username: sonica05).

2️⃣ Tag your image

docker tag flask-app sonica05/flask-app:latest

3️⃣ Push to Docker Hub

docker push sonica05/flask-app:latest

---

✅ What You Learned

• How to run a Flask app in Docker

• Deploy it on EC2 with Amazon Linux 2023

• Push your Docker image to Docker Hub

---

Thanks for reading! 🙌