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. Docker for Developers
Chris Tankersley
@dragonmantank
Lonestar PHP 2016
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2. Who Am I
• PHP Programmer for over 11 years
• Sysadmin/DevOps for around 9 years
• Using Linux for more than 15 years
• hGps://github.com/dragonmantank
• Author of “Docker for Developers”
• Reigning, Defending, Undisputed PHP
MTG Champion of the World
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3. Docker
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4. What Is Docker?
“Docker is an open plaUorm for developers and sysadmins to build,
ship, and run distributed applicaVons. ConsisVng of Docker Engine, a
portable, lightweight runVme and packaging tool, and Docker Hub, a
cloud service for sharing applicaVons and automaVng workflows,
Docker enables apps to be quickly assembled from components and
eliminates the fricVon between development, QA, and producVon
environments.”
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hGps://www.docker.com/whaVsdocker/

5. What is it from a technical standpoint?
• Docker is a wrapper around Containers
• Docker Engine is the packaging porVon 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 mulV-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
OperaVng System
nginx PHP DB

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

9. Containers
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CPU RAM HD Network
OperaVng System
nginx nginx 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. Runs on *nix and Windows Hyper-V
• No naVve container drivers for OSX*
• Amazon has ElasVc Container Service, and Microsok Azure has Azure
Container Service
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12. Sorry OSX Users
• Docker support is officially maintained through Docker Toolbox
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13. Docker Toolbox also is for Windows
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14. Let’s use Docker
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15. Running a container
• `docker run` will run a container
• This will not restart an exisVng container, just create a new one
• docker run [opVons] IMAGE [command] [arguments]
• [opVons ]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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16. Running a simple shell
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17. Running Two Webservers
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18. 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 interacVve mode
• --name – Give the container a name
• -p [local port]:[container port] – Forward the local port to the container port
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19. Volumes
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20. Modifying a running container
• `docker exec` can run a command inside of an exisVng container
• Use Volumes to share data
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21. 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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22. Mounting from the host machine
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23. 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
• Docker Toolbox’s VM only allows mounVng from within your home
directory
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24. 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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25. Mounting Data Volumes
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26. 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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27. Why go through the hassle?
• Data volumes are portable
• Data volumes are safer
• Separates the app containers from data
• ProducVon can use a data volume, dev can use a host volume
• Our app containers stay small
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28. Network Linking
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29. 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
• Currently only works if all the containers are on one machine, Docker
1.10 should fix that
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30. More Traditional Setup
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INTARWEBS Nginx PHP-FPM
Data Volume
Port 9000
Editor

31. Let’s Build It
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32. More Notes!
• We can now rebuild secVons of the app as needed
• We can restart nginx without impacVng 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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33. Creating your own Images
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34. Dockerfile
• Dockerfile is the configuraVon 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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35. 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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36. 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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37. Other Helpful Commands
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38. Inspect a container
docker inspect [opVons] CONTAINER_NAME
• Returns a JSON string with data about the container
• Can also query
• docker inspect -f “{{ .NetworkSe{ngs.IPAddres }}” web_server
• Really handy for scripVng out things like reverse proxies
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39. 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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40. Docker Machine
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41. What is Docker Machine?
• A provisioning tool that is used to set up a box with Docker
• Used in Docker Toolbox to create the VM
• Supports:
• EC2
• Azure
• Digital Ocean
• Hyper-V
• OpenStack
• Virtualbox
• VMWare
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42. Creating a new machine
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43. Why use it?
• Makes it very easy to spin up new boxes
• Docker Machine handles all of the dirty stuff for you
• Docker Toolbox users are already using it
• Integrates with Docker Swarm
• It is not necessarily portable
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44. Docker Swarm
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45. What is Docker Swarm?
• Cluster management tool developed by Docker
• Looks like a machine running docker, but is actually many machines
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46. Create a Swarm token
$ docker run --rm swarm create 2
//...
340122bb69c98825b4ac7094c87a07e21
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47. Create a Swarm Master
$ docker-machine create -d virtualbox
--swarm
--swarm-master
--swarm-discovery token://40122bb69c98825b4ac7094c87a07e21
swarm-master
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48. Add nodes to the swarm
docker-machine create -d virtualbox
--swarm
--swarm-discovery token://40122bb69c98825b4ac7094c87a07e21
swarm-node-1
docker-machine create -d virtualbox
--swarm
--swarm-discovery token://40122bb69c98825b4ac7094c87a07e21
swarm-node-2
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49. Switch to the master
eval $(docker-machine env --swarm swarm-master)
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50. Add some containers
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51. Docker Compose
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52. What is Docker Compose?
• MulV-container orchestraVon
• A single config file holds all of your container info
• Works with Docker Swarm and a few other tools, like Rancher
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53. Sample docker-compose.yml
phpserver:
build: ./docker/php
volumes:
- /home/ctankersley/Projects/dockerfordevs:/var/www/
links:
- mysqlserver
mysqlserver:
image: mysql
environment:
MYSQL_DATABASE: dockerfordevs
MYSQL_ROOT_PASSWORD: docker
volumes:
- /var/lib/mysql
nginx:
build: ./docker/nginx
ports:
- "80:80"
- "443:443"
links:
- phpserver
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54. Docker Compose in Action
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55. Let’s build an application
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56. The Goal
• A three container applicaVon with nginx, php, and mysql
• ApplicaVon will read and write to the database
• Can deploy to a producVon machine
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57. Folder Structure
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58. A basic docker-compose.yml
phpserver:
image: php:7-fpm
volumes:
- ./application:/var/www/
nginx:
image: nginx
ports:
- "80:80"
- "443:443"
volumes:
- ./nginx:/etc/nginx/conf.d/
links:
- phpserver
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59. nginx/nginx.conf
server {
listen 80;
root /var/www/html;
index index.html index.htm index.php;
access_log /dev/stdout;
error_log /dev/stderr;
location / {
try_files $uri $uri/ /index.html /index.php?$query_string;
}
location ~ .php$ {
fastcgi_split_path_info ^(.+.php)(/.+)$;
fastcgi_pass phpserver:9000;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include fastcgi_params;
}
}
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60. Hello World
<?php
echo "Hello World";
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61. Bringing it to life
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62. Adding in MySQL
phpserver:
image: php:7-fpm
volumes:
- ./application:/var/www/
links:
- mysqlserver
mysqlserver:
image: mysql
environment:
MYSQL_DATABASE: dockerfordevs
MYSQL_ROOT_PASSWORD: docker
volumes:
- /var/lib/mysql
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63. Docker Compose changes aren’t
automatic
• You will need to stop, then bring the system again
• docker-compose stop
• docker-compose up
• Docker Compose will generally only restart boxes that have config
changes
• Docker Compose will not automaVcally fix links
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64. Connecting to the database
<?php
$hostname = 'mysqlserver';
$database = 'dockerfordevs';
$user = 'root';
$password = 'docker';
$dbh = new PDO('mysql:host=' . $hostname . ';dbname=' . $database . '', $user, $password);
echo 'Hello World';
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65. Testing it
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66. Why didn’t it work?
• Default PHP images ship with barely any extensions enabled by
default
• We will need a custom PHP Image
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67. Update our docker-compose.yml
phpserver:
build: ./docker/php
volumes:
- ./application:/var/www/
links:
- mysqlserver
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68. Custom Docker File
FROM php:7-fpm
# Install modules
RUN apt-get update && apt-get install -y
libmcrypt-dev
&& docker-php-ext-install pdo
&& docker-php-ext-install pdo_mysql
CMD ["php-fpm"]
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69. Let’s try that again
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70. Deploying
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71. I can’t answer this for you
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¯_(ツ)_/¯

72. Questions?
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73. Each situation is different
• You will probably build something custom, using exisVng tools
• Do you use data volumes?
• Do you just package the enVre compiled app?
• Does it need to be distributed?
• Is it going on Swarm, or Amazon ECS?
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74. Things to consider
• Docker Compose will only deploy an app to one server
• Docker Swarm is preGy low-level and bare-bones
• Volumes on Swarm cannot be shared across hosts
• Host mounVng is 99.99999% of the Vme not what you want to do
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75. Rancher is a good start
• Provides a nice GUI to manage everything
• Allows volume sharing and networking across hosts
• Works with docker-compose.yml files
• These files can be supplemented with environment variables
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76. Rancher in action
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77. Questions?
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78. http://ctankersley.com
chris@ctankersley.com
@dragonmantank
https://joind.in/talk/2d8b6
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