Скачать или смотреть Deploying Flask App on a VPS with Nginx and Docker

A complete guide on how to successfully deploy your `Flask` application on a VPS using `Nginx` and `Docker`. Learn essential configurations step-by-step!
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This video is based on the question https://stackoverflow.com/q/63896945/ asked by the user 'Filip Bartoš' ( https://stackoverflow.com/u/6904228/ ) and on the answer https://stackoverflow.com/a/63897348/ provided by the user 'anemyte' ( https://stackoverflow.com/u/11344502/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Deploying Your Flask App on a VPS with Nginx and Docker

Deploying web applications can often be a complex task, especially when it comes to integrating multiple technologies like Docker, Nginx, and Flask. If you've previously set up your Flask app without using Docker but now want to take advantage of containerization, you might run into a few hiccups. In this guide, we'll walk you through the common challenges you might encounter when deploying a Flask app with Nginx and Docker, and provide practical solutions to streamline the process.

Understanding the Problem

When deploying a Flask application using Docker, users might encounter issues where the Nginx server cannot locate the Flask application container. Specifically, the challenge arises when configuring Nginx to communicate correctly with the Docker container running the Flask application, especially when using a docker-compose.yml setup.

In this scenario, the user received the following error while testing Nginx configurations:

[[See Video to Reveal this Text or Code Snippet]]

This error indicates that Nginx cannot resolve the hostname myapp which should correspond to the Docker container running the Flask app.

Proposed Solutions

We can resolve this communication issue between Nginx and your Dockerized Flask application using a few methods. Let’s break these down into actionable steps:

Solution 1: Using Host Ports

To allow Nginx running on your VPS to communicate with the Flask application in Docker, you can expose the application's port to the host. Here’s how you can do that:

Modify your docker-compose.yml file to add a ports mapping:

[[See Video to Reveal this Text or Code Snippet]]

Reflect this change in your Nginx configuration to point to localhost:

[[See Video to Reveal this Text or Code Snippet]]

Solution 2: Reverting to Unix Sockets

If you prefer to continue using Unix sockets rather than exposing ports, you can set up your Docker container to write the socket to a directory on the host. Here's how:

Modify your docker-compose.yml file to mount a volume:

[[See Video to Reveal this Text or Code Snippet]]

Configure your Flask application to create the socket file in the /tmp directory:

In your UWSGI configuration file, change:

[[See Video to Reveal this Text or Code Snippet]]

To:

[[See Video to Reveal this Text or Code Snippet]]

Lastly, adjust your Nginx configuration to utilize the Unix socket:

[[See Video to Reveal this Text or Code Snippet]]

Summary

Deploying a Flask application using Docker and Nginx on a VPS offers a proficient way to manage your application’s infrastructure. By following the above solutions, you can ensure that your Flask app will seamlessly communicate with Nginx, either through host ports or Unix sockets based on your preferences.

By implementing these configurations, you should be well on your way to a successful deployment. If you encounter issues or have any questions, feel free to reach out!