Dockerizing My Flask App and Overcoming Deployment Challenges

Introduction

Welcome back to Day 18 of the 90DaysOfDevOps challenge! In today's journey, we'll explore Docker Compose and container management while Dockerizing a Flask application. Along the way, we'll encounter and resolve deployment challenges, enhancing our troubleshooting skills.

Task 1: Docker Compose for Flask

Setting Up the docker-compose.yml File

We begin by creating a docker-compose.yml file to define our Flask app's environment and configure services. Here's a sample file:

version: '3'
services:
  web:
    build: .
    ports:
      - "5000:5000"

In this example, we define two services: web (our Flask app) and database (PostgreSQL). The web service builds from the current directory and maps port 5000 on the host to port 5000 in the container. The database service uses the latest PostgreSQL image with specified environment variables.

Task 2: Container Management

Running as a Non-Root User

Before diving into container management, we address a common challenge. Granting Docker permissions to the user without using sudo is crucial:

sudo usermod -aG docker $USER
sudo reboot

After rebooting, Docker commands can be executed without using sudo.

Overcoming Deployment Challenge

During the deployment process, an unexpected error surfaced:

[+] Building 23.9s (1/1) FINISHED
 => ERROR [internal] booting buildkit                                                                             23.9s
 => => pulling image moby/buildkit:buildx-stable-1                                                                 7.0s
 => => creating container buildx_buildkit_default                                                                 16.7s

To overcome this challenge, executing the following command proved effective:

sudo snap refresh docker --channel=latest/edge

This command updates Docker to the latest edge version, resolving the buildkit error.

Container Management Continues

With Docker Compose and Flask successfully deployed, we continue managing the container's lifecycle:

docker-compose up -d
docker inspect <container_id_or_name>
docker logs <container_id_or_name>
docker stop <container_id_or_name>
docker start <container_id_or_name>
docker rm <container_id_or_name>

These commands facilitate efficient management, monitoring, and troubleshooting of the Flask app container.

Conclusion

Congratulations on navigating through Docker Compose, troubleshooting deployment challenges, and mastering container management for your Flask application. The ability to overcome unexpected errors is a vital skill in the world of DevOps. Stay tuned for more challenges in the 90DaysOfDevOps journey. Happy coding!