Docker allows wrapping software in containers that contain everything needed to run. Images are templates for containers. This document discusses using Docker to set up a Django project with linked Django and database containers. It provides an overview of the development process, which includes creating Dockerfiles and docker-compose files to build images for the Django and database containers. Useful Docker commands are also listed.

1. Django + Docker
Super easy setup
https://github.com/brendenwest/django-demo

2. Installation & Docs
- Overview : https://docs.docker.com/engine/understanding-docker/
- Django images: https://hub.docker.com/_/django/
- Django quickstart: https://docs.docker.com/compose/django/
- MySQL images: https://hub.docker.com/r/mysql/mysql-server/

3. Terminology
Docker containers wrap a piece of software in a complete filesystem that contains
everything needed to run: code, runtime, system tools, system libraries – anything
that can be installed on a server.
- Image - A binary image with stacked read-only layers representing file system
differences.
- Container - A running instance of a Docker image, with a thin, writable layer
for all changes made to the container - such as writing new files, modifying
existing files, and deleting files. When the container is deleted the writable
layer is also deleted.

5. Microservices - Linked Single-purpose Containers
Docker Host
Django
Container
DB
Container

6. Dev Process Overview
One time
1. Install virtualbox
2. Install Docker
Per Project
1. Create project directory
2. Start docker machine
3. Create Docker image for Django 1
4. Create MySQL docker image 1
5. Create initial Django project 2
6. Update settings.py database config
7. Start Docker container(s)
1 - Can be one-time step if project doesn’t require image customization
2 - if project doesn’t already exist

7. Creating a Django image
Create the following files:
Dockerfile - Django image specifications
Requirements.txt - python environment specifications
docker-compose.yml (optional) - Django container runtime settings
Image can be created via command line or docker-compose.yml:
$ docker build -t <IMAGE_NAME> .
$ docker-compose up -d

8. Creating a DB image
Optional - You can use Django image default settings instead
DB can be any valid Django data store (SQLite, MySQL, PostgreSQL)
DB can be specified in docker-compose.yml, or via dedicated Dockerfile
Django container needs to reference ports exposed by DB container
DB data storage can be packaged in container or on external ‘volume’

9. Useful Docker Commands
docker-machine start
eval "$(docker-machine env default)"
docker-machine ip
docker-compose up
docker-compose up -d
docker ps
docker exec -it <container> bash
docker start/stop <container>