Thanks to tools like vagrant, puppet/chef, and Platform as a Service services like Heroku, developers are extremely used to being able to spin up a development environment that is the same every time. What if we could go a step further and make sure our development environment is not only using the same software, but 100% configured and set up like production. Docker will let us do that, and so much more. We'll look at what Docker is, why you should look into using it, and all of the features that developers can take advantage of.

1. Dockerize All The Things!
Chris Tankersley
@dragonmantank
SunshinePHP 2015
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2. Who Am I
• PHP Programmer for over 10 years
• Sysadmin/DevOps for around 8 years
• Using Linux for more than 15 years
• https://github.com/dragonmantank
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3. Docker
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4. What Is Docker?
“Docker is an open platform for developers and sysadmins to build,
ship, and run distributed applications. Consisting of Docker Engine, a
portable, lightweight runtime and packaging tool, and Docker Hub, a
cloud service for sharing applications and automating workflows,
Docker enables apps to be quickly assembled from components and
eliminates the friction between development, QA, and production
environments.”
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https://www.docker.com/whatisdocker/

5. What is it from a technical standpoint?
• Docker is a wrapper around Containers
• Docker Engine is the packaging portion that builds and runs the
containers
• Docker Hub allows you to publish images for others to use
• Docker Machine is a bare-metal provisioning tool
• Docker Swarm is an load-balancing deployment tool
• Docker Compose is a multi-container build system
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6. Containers
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7. Normal Bare-Metal Server
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CPU RAM HD Network
Operating System
nginx PHP DB

8. Virtual Machines
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CPU RAM HD Network
Operating System
nginx PHP DB
Operating System
nginx PHP DB
Operating System
Hypervisor

9. Containers
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CPU RAM HD Network
Operating System
nginxnginx PHP DB PHP DB

10. Docker can use many different containers
• Since 0.9.0 it supports:
• LXC (Linux Containers) – Started with LXC when it was released
• OpenVZ
• Systemd-nspawn
• libvert-sandbox
• Qemu/kvm
• BSD Jails
• Solaris Zones
• chroot
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11. Still regulated to Linux, BSD, and Solaris
• No native container drivers for OSX or Windows, as they don’t have
their own container architecture
• Microsoft is helping with working on a Hyper-V container driver
though
• I don’t think there is anything native planned for OSX
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12. Let’s use Docker
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13. Running a container
• `docker run` will run a container
• This will not restart an existing container, just create a new one
• docker run [options] IMAGE [command] [arguments]
• [options ]modify the docker process for this container
• IMAGE is the image to use
• [command] is the command to run inside the container
• [arguments] are arguments for the command
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14. Running a simple shell
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15. Running Two Webservers
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16. Some Notes
• All three containers are 100% self contained
• Docker containers share common ancestors, but keep their own files
• `docker run` parameters:
• --rm – Destroy a container once it exits
• -d – Run in the background (daemon mode)
• -i – Run in interactive mode
• --name – Give the container a name
• -p [local port]:[container port] – Forward the local port to the container port
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17. Volumes
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18. Modifying a running container
• `docker exec` can run a command inside of an existing container
• Use Volumes to share data
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19. Persistent Data with Volumes
• You can designate a volume with -v
• Volumes can be shared amongst containers
• Volumes can mount data from the host system
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20. Mounting from the host machine
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21. Mounting from the host isn’t perfect
• The container now has a window into your host machine
• Permissions can get screwy if you are modifying in the container
• Most things it creates will be root by default, and you probably aren’t root on
the host machine
• Host-mounted volumes are not portable at all
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22. Container Data Volumes
• Uses a small container that does nothing but stores data
• Have our app containers use the data volume to store data
• Use ‘editor containers’ to go in and modify data when needed
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23. Mounting Data Volumes
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24. Why not run SSH inside of the container?
• Well, you can…
• Docker is designed for one command per container
• If you need to modify data, then you need to change your setup
• If you have to run SSH, then you need a way to run SSH and your
command
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25. Why go through the hassle?
• Data volumes are portable
• Data volumes are safer
• Separates the app containers from data
• Production can use a data volume, dev can use a host volume
• Our app containers stay small
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26. Network Linking
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27. Docker Links
• Allows containers to ‘see’ each other over the network
• Each container thinks the other one is just another machine
• Containers all have an internal network address, so we don’t need to
expose everything through the host
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28. More Traditional Setup
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INTARWEBS Nginx PHP-FPM
Data Volume
Port 9000
Editor

29. Let’s Build It
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30. More Notes!
• We can now rebuild sections of the app as needed
• We can restart nginx without impacting PHP
• We can extend much easier
• Linked containers will not update if they are stopped/started
• If we upgrade PHP, we have to destroy/create the web_server container again
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31. Creating your own Images
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32. Dockerfile
• Dockerfile is the configuration steps for an image
• Can be created from scratch, or based on another image
• Allows you to add files, create default volumes, ports, etc
• Can be used privately or pushed to Docker Hub
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33. FROM phusion/baseimage:0.9.10
# …
CMD ["/sbin/my_init"]
# Nginx-PHP Installation
RUN apt-get update
RUN apt-get install -y vim git curl wget build-essential python-software-properties
php5-cli php5-fpm php5-mysql php5-pgsql php5-sqlite php5-curl
php5-gd php5-mcrypt php5-intl php5-imap php5-tidy mysql-client
# …
RUN mkdir /var/www
ADD build/default /etc/nginx/sites-available/default
# …
EXPOSE 80 22
VOLUME /var/www
VOLUME /etc/nginx
VOLUME /etc/php/
VOLUME /var/log
RUN apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
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34. Build it
docker build -t tag_name ./
• This runs through the Dockerfile and generates the image
• We can now use the tag name to run the image
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35. Other Helpful Commands
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36. Inspect a container
docker inspect [options] CONTAINER_NAME
• Returns a JSON string with data about the container
• Can also query
• docker inspect -f “{{ .NetworkSettings.IPAddres }}” web_server
• Really handy for scripting out things like reverse proxies
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37. Work with images
• docker pull IMAGE – Pulls down an image before using
• docker images – Lists all the images that are downloaded
• docker rmi IMAGE – Deletes an image if it’s not being used
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38. Questions?
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39. http://ctankersley.com
chris@ctankersley.com
@dragonmantank
https://joind.in/13464
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