This document provides an overview of Docker and how it can be used to build Python web apps. It describes Docker as an alternative to virtual machines for containerizing applications using lightweight Linux containers. It covers Docker Engine for building images and running containers, Docker Hub for sharing images, Docker Compose for defining multi-container apps, and Docker Machine for provisioning Docker hosts in various environments. It also provides a demo Python web app as an example and leaves time at the end for any additional questions.

1. Building Python
Web Apps with
Docker
Mark Adams • Bitbucket Developer • Atlassian • @markadams

2. What we'll cover (hopefully)
What is Docker?
A Python web app
Docker Engine
Docker Hub
Docker Compose
Docker Machine

3. What is
???

4. Traditional Virtual Machines
APP A APP B
LIBS LIBS
GUEST OS GUEST OS
HYPERVISOR
HOST OS
SERVER
Robust
Monolithic
Slow to
boot
Heavy

5. Containers
APP A APP B
LIBS LIBS DOCKER
HOST OS
SERVER
Lean
Portable
Lightweight
Efficient
Isolated

6. Where are containers useful?

10. Local Development

11. CI Builds
Jenkins, Bamboo, etc.

12. Deploying to production
and scaling!

14. Where do I get it?

15. Windows & Mac
Docker Toolbox
Installs Docker Client, Engine, Compose,
Machine, Kitematic, and Virtualbox

16. Linux
$ wget ­qO­ https://get.docker.com/ | sh
Downloads a shell script to install the right package for your system

17. Architecture

18. Demo App!
https://bitbucket.org/markadams/pytexas-2015-demo

19. Docker Engine
Builds images and runs containers
Dockerfile
FROM python:3.4
EXPOSE 8000
WORKDIR /usr/src/app
# Install dependencies
COPY requirements.txt requirements.txt
RUN pip install ­r requirements.txt
# Copy the rest of the application's code
COPY . /usr/src/app
# Run the app
CMD ["./run_app.sh"]
docker build
builds an image
docker run
creates a container from an image and runs it
docker logs
shows the logs from a container
docker ps
shows what's running

20. Docker Hub
http://hub.docker.com
$ docker pull ubuntu
Using default tag: latest
latest: Pulling from ubuntu
Downloading 10.8 MB/158.6 MB
fec9fec2e960: Download complete
9f834db6fd2c: Download complete
Downloading 5.7 MB/30.2 MB
b13fbdab1f72: Download complete
843e2bded498: Already exists
docker push
pushes to the repository
docker pull
pulls an image from the repository
Public or Private

21. Docker Compose
Describes the components of an application
YML Config
web:
build: .
links:
­ 'db'
ports:
­ '8000:8000'
environment:
­ 'DATABASE_HOST=db'
­ 'DATABASE_NAME=postgres'
­ 'DATABASE_USER=postgres'
­ 'DATABASE_PASSWORD=postgres'
db:
image: postgres:9.4
docker-compose up
starts all the containers
docker-compose
build
rebuilds your images
docker-compose stop
stopps the containers

22. Docker Machine
Provisions and manages Docker hosts
Works with
­ amazonec2
­ azure
­ digitalocean
­ exoscale
­ google
­ openstack
­ rackspace
­ softlayer
­ virtualbox
­ vmwarevcloudair
­ vmwarevsphere
docker-machine create
creates a new Docker host
docker-machine ssh
connects to the host using SSH
docker-machine rm
destroys the host
docker-machine env
sets environment variables for your client to
connect to the host

23. Demo
2:15

24. Orchestration!

25. Thank you!
@markadams
https://bitbucket.org/markadams/pytexas-2015