Deploying Your First Django Application as a Docker Container

This blog post covers the process of deploying a Django web application as a Docker container, including the necessary prerequisites, the workflow of a Django application, and the steps to containerize the application effectively.

Today marks Day 25 of our complete DevOps course, where we will deploy our first Django web application as a Docker container. This session builds on the concepts we discussed in previous classes, particularly Day 23 and Day 24, where we explored the fundamentals of containers and Docker architecture.

Recap of Previous Classes

In the earlier sessions, we focused on:

Understanding the concept of containers and their lightweight nature compared to virtual machines.
Exploring the files and folders that make up a container and how they differ from virtual machines.
Learning about Docker's architecture and lifecycle.
Installing Docker on an EC2 instance and addressing common permission issues.
Running a simple Docker CLI application.

If you haven't watched those videos yet, I highly recommend doing so, as they are essential for grasping today's topic.

Overview of the Django Application

Today, we will work with a basic Django application. This application is straightforward, and the process of containerizing it will be similar regardless of whether it has one page or multiple pages. As a DevOps engineer, understanding how to containerize a Django application is crucial, even if you are not a developer.

Do You Need Programming Experience?

A common question I receive is whether programming experience is necessary for containerizing applications. While you don't need to be a programming expert, having a basic understanding of how applications function is essential. You should be able to recognize how different components of a Django application interact, such as the settings, views, and templates.

Understanding the Workflow of a Django Application

Before we dive into containerization, let’s briefly discuss the workflow of a Django application:

Installation: Start by installing Python and Django using the pip command.
Project Creation: Use the command django-admin startproject <project_name> to create a new Django project.
Application Creation: Inside the project, create applications using python manage.py startapp <app_name>. This generates the necessary files for your application.
Configuration: The settings.py file contains configurations such as database connections and middleware settings.
URL Routing: The urls.py file manages the routing of requests to the appropriate views.
Views and Templates: The views.py file contains the logic for rendering templates, which are stored in a templates folder.

Understanding this workflow is vital for effectively containerizing a Django application.

Containerizing the Django Application

Step 1: Writing the Dockerfile

To containerize the Django application, the first step is to create a Dockerfile. Here’s a brief overview of the process:

Choose a Base Image: Start with a base image, such as Ubuntu.
Set the Working Directory: Define a working directory where your source code will reside.
Copy Dependencies: Copy the requirements.txt file to the working directory and install the necessary dependencies using pip.
Copy Source Code: Copy the source code of your Django application into the container.
Define Entry Point and CMD: Specify the entry point and command to run your application.

Step 2: Building the Docker Image

Once the Dockerfile is ready, you can build the Docker image using the command:

docker build -t <image_name> .

This command compiles your application into a Docker image.

Step 3: Running the Docker Container

To run the container, use the command:

docker run -p 8000:8000 <image_name>

This command maps port 8000 of the container to port 8000 on your host machine, allowing you to access the application via your browser.

Common Issues and Solutions

If you encounter issues while running your application, consider the following:

Ensure that the port is correctly mapped.
Check your security group settings in AWS to allow inbound traffic on the specified port.

Conclusion

In this session, we successfully containerized a Django web application using Docker. The process involves understanding the workflow of a Django application, writing a Dockerfile, building the Docker image, and running the container.

For those who want to practice, I encourage you to clone the repository and try containerizing the application on your own. If you have any questions or run into issues, feel free to leave a comment, and I will assist you.

In the next class, we will cover Docker commands, networking, and how to reduce the size of your containers using multi-stage builds. Thank you for joining me today, and I look forward to seeing you in the next video!

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