Docker allows developers to package applications and dependencies into standardized containers. Containers provide isolated environments that are consistent across different machines. This document outlines how Docker can be used to develop PHP applications, including building containers with Dockerfiles, sharing containers via Docker Hub, and running multi-container applications with Docker Compose. The speaker demonstrates building, shipping, and running containers to illustrate Docker's capabilities.

2. Docker for developers
#drupalday2015

3. Paolo Mainardi (@paolomainardi)
● CTO @sparkfabrik
● Drupal developer
● Docker enthusiast (dropdock.io, dockerhub@paolomainardi)
● Twin of @stefanomainardi
● Linux and open source lover (ildn.net)

4. Let’s start with
questions

5. ● You read the online tutorial
● You installed docker locally
● You are using for development
● You are using on production
Raise your hands if

6. Outlines
● What is Docker and why it is important to know it.
● What a container is and how to use it.
● Developing PHP applications using Docker.
● Tips and tricks on real world usage.

7. ● To make your local development and build workflow faster, more efficient, and
more lightweight.
○ If it works on my machine, it will work in production
○ No more dependency hell, different versions of PHP with their own
libraries, Mysql or Mariadb, Redis or Memcache, Sass or Less
compilers, NPM etc.etc.
○ Consistent development environment, same operating system, same
libraries, no matter the host operating system you are running.
○ Easy way to replicate production environment.
○ Concentrate on code, instead to (re)build the infrastructure your
application needs.
Ok, what can I use Docker for ?

8. What is Docker?

9. What is Docker ?
“Docker allows you to package an
application with all of its dependencies
into a standardized unit for software
development.”
https://www.docker.com/what-docker

10. How it is made Docker ?
● It relies on standard linux kernel features only (cgroups, namespaces,
capabilities ecc.)
● Static compiled binary based on golang, no extra moving parts.
● It natively runs on every linux distro and on mac/windows too thanks to
boot2docker vm. (https://www.docker.com/docker-toolbox)
● Fast and lightweight, no added overhead.
● Security by process isolation.
● Open container initiative also baked by Docker inc. (https://www.
opencontainers.org)

11. Virtual machines Containers
Docker is not virtualization

12. What is a container ?

13. What is a container ?
● It is a linux process.
● It sits on top of the base docker image
(usually an operating system image).
● It has its own network interface.
● It has its own process namespace.

14. Demo time

15. Docker is a platform
Docker is an open source platform to build, ship and run any app, anywhere.
● Build: Package your application in a container.
● Ship: Move that container from one host to another.
● Run: Execute your application.
● Any app: that runs on Linux (recently native Windows support)
● Anywhere: Local, remote, cloud, VM, RaspberryPI ecc. any platform capable
to run the docker engine.

16. Build: Dockerfiles
A “Dockerfile” is a text document that contains all the
commands to assemble a docker image in a programmatic
and reproducible way.

17. Build: Dockerfiles
FROM ubuntu:14.04
RUN apt-get update && apt-get install -y nginx
RUN echo 'Hi, I am in your container'
>/usr/share/nginx/html/index.html
CMD nginx -g "daemon off;"
EXPOSE 80
$ docker build -t paolomainardi/dday15web .
$ docker run -d -P paolomainardi/dday15web

18. BUILD DEMO

19. Build: What we learned
● It allows to create a docker image in
a programmatic and reproducible
way.
● Each build step gets cached (thanks
to overlaid filesystem)
● Re-run the build allows to skip slow
steps (ex: apt-get install)

20. Ship

21. Ship: Dockerhub
● git pull
● git push

22. Ship: Dockerhub
● git docker pull image from the registry
● git docker push image to the registry
http://hub.docker.com

23. SHIP TO DOCKERHUB DEMO

24. Ship: What we learned
● It mimics the git workflow.
● Images are self-contained, independent from the host.
● Exactly the same behaviour, on any environment.
● To easily replicate and share the environment your application expects.
● No more “it worked on my machine” excuse.

25. Run
docker run is-lightning-fast

26. RUN DEMO

27. Run: What we learned
● Execution is fast and lightweight.
● There is no overhead, they are just normal OS running processes.
● Containers are isolated.

28. Any app, anywhere
● If it works on Linux, it works on Docker.
● Not just for command-line apps
○ Chrome-in-docker
○ Firefox-in-docker
○ VPN-in-docker
○ etc…follow this repo to see crazy things: https://github.com/jfrazelle/dockerfiles
● Every linux host that run Linux 3.8+ x86_64 kernel

29. Developing PHP applications using Docker

30. Developing PHP applications using Docker

31. Developing PHP applications using Docker

32. Docker Compose to rule them all

33. Docker compose
● Describe your stack in one file docker-compose.yml
● Run your stack with a command docker-compose up

34. front:
image: drupal:7.41
volumes:
- ./sites/all/modules:/var/www/html/sites/all/modules
ports:
- "8080:80"
links:
- mariadb:mariadb
mariadb:
image: mariadb:10
ports:
- "3306:3306"
environment:
- MYSQL_ROOT_PASSWORD=root
- MYSQL_DATABASE=drupal
memcached:
image: memcached:1.4.25
ports:
- "1211:1211"
solr:
image: sparkfabrik/drupal-drupal-solr
ports:
- "8983:8983"
docker-compose-yml

35. DOCKER COMPOSE DEMO

36. The Docker ecosystem
When talk about Docker, we talk about an ecosystem of tools.
● Docker engine: Client and server daemon to build, ship and run containers.
● Docker hub: The official Docker image registry.
● Docker compose: Tool to orchestrate multi-container applications.
● Docker machine: Automated Docker hosts provisioning.
● Docker swarm: Host clustering and container scheduling.
Much more than this, check it out: https://www.docker.com/products/overview