Lesson 7.1: Hosting with Docker

 

🧱 Lesson 7.1: Hosting with Docker

🎯 Learning Objectives

By the end of this lesson, learners will:

  • Understand containerization and the purpose of Docker in app deployment.

  • Create a Dockerfile for their AI chatbot backend.

  • Build and run containers locally.

  • Use Docker Compose for multi-service apps (e.g., backend + database).

  • Push Docker images to Docker Hub.

  • Deploy Docker containers to the cloud (Render, Fly.io, or VPS).

🧠 Core Concepts

💡 What is Docker?

Docker is a containerization tool that packages your application and its dependencies into a single unit called a container. Unlike traditional deployment methods, containers ensure your app runs the same across all environments—dev, test, or production.

🗃️ Key Docker Components:

  • Dockerfile – A script to build a Docker image.

  • Docker Image – A snapshot of your app and its environment.

  • Docker Container – A running instance of an image.

  • Docker Hub – A public/private registry to host and share images.

  • Docker Compose – A tool to manage multi-container apps using a YAML file.

🧪 Hands-On Walkthrough

🔧 Step 1: Install Docker

📁 Step 2: Create Your Dockerfile

Example for a FastAPI backend:

# Use official Python base image
FROM python:3.11-slim

# Set working directory
WORKDIR /app

# Copy requirements and install
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Copy project files
COPY . .

# Run app
CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]

🧷 Step 3: Create Docker Compose File (Optional)

Useful for connecting backend + database or frontend:

version: "3.8"
services:
  backend:
    build: .
    ports:
      - "8000:8000"
    env_file:
      - .env

🔨 Step 4: Build & Run the Container Locally

# Build your image
docker build -t my-chatbot .

# Run it
docker run -p 8000:8000 my-chatbot

Or using Compose:

docker-compose up --build

Visit: http://localhost:8000

🛰️ Step 5: Push to Docker Hub

# Login to Docker Hub
docker login

# Tag your image
docker tag my-chatbot yourusername/my-chatbot:latest

# Push it
docker push yourusername/my-chatbot:latest

🌍 Step 6: Deploy to a Hosting Provider (Render or VPS)

Option A: Render (Docker Deploy)

  • Sign up at render.com.

  • Create a new Web Service.

  • Choose Docker as deployment method.

  • Connect GitHub repo or use Docker Hub image.

Option B: VPS (like DigitalOcean)

  • Spin up a server (Ubuntu).

  • Install Docker & Docker Compose:

    sudo apt update
sudo apt install docker.io docker-compose

  • Clone your repo and run:

    docker-compose up --build -d

🔐 Best Practices for Docker Hosting

  • Use .env files for secrets and API keys.

  • Keep your image size small by using python:3.11-slim or Alpine images.

  • Use multi-stage builds for better performance (for Node or React apps).

  • Expose only necessary ports (e.g., 8000).

  • Use .dockerignore to avoid copying unwanted files (like .git or __pycache__).

Example .dockerignore:

__pycache__
*.pyc
.git
.env

📝 Assignments & Practice

  • ✅ Dockerize your chatbot backend.

  • ✅ Push the image to Docker Hub.

  • ✅ Deploy it on Render using Docker.

📦 Downloads Included

  • Sample Dockerfile (FastAPI)

  • Sample docker-compose.yml

  • .dockerignore template

  • Step-by-step PDF deployment guide

📚 Further Learning

 

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