1. Docker for Developers
Chris Tankersley
@dragonmantank
SunshinePHP 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 Microsoj 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. Assumptions
• OSX and Windows users have Docker Toolbox installed
• Linux users have the naVve binaries installed
• The following images are downloaded:
• php:7-fpm
• php:7-cli
• nginx
• mysql
• composer/composer
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16. 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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17. Running a simple shell
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18. Running Two Webservers
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19. 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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20. Volumes
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21. Modifying a running container
• `docker exec` can run a command inside of an exisVng container
• Use Volumes to share data
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22. 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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23. Mounting from the host machine
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24. 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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25. 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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26. Mounting Data Volumes
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27. 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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28. 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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29. Network Linking
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30. 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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31. More Traditional Setup
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INTARWEBS Nginx PHP-FPM
Data Volume
Port 9000
Editor

32. Let’s Build It
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33. 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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34. Creating your own Images
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35. 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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36. 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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37. 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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38. Other Helpful Commands
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39. Inspect a container
docker inspect [opVons] CONTAINER_NAME
• Returns a JSON string with data about the container
• Can also query
• docker inspect -f “{{ .NetworkSezngs.IPAddres }}” web_server
• Really handy for scripVng out things like reverse proxies
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40. 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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41. Docker Machine
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42. 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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43. Creating a new machine
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44. 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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45. Docker Swarm
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46. 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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47. Create a Swarm token
$ docker run --rm swarm create 2
//...
340122bb69c98825b4ac7094c87a07e21
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48. Create a Swarm Master
$ docker-machine create -d virtualbox
--swarm
--swarm-master
--swarm-discovery token://40122bb69c98825b4ac7094c87a07e21
swarm-master
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49. 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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50. Switch to the master
eval $(docker-machine env --swarm swarm-master)
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51. Add some containers
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52. Docker Compose
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53. 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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54. 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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55. Docker Compose in Action
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56. Let’s build an application
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57. 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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58. Folder Structure
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59. 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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60. 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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61. Hello World
<?php
echo "Hello World";
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62. Bringing it to life
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63. 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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64. 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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65. 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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66. Testing it
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67. 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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68. Update our docker-compose.yml
phpserver:
build: ./docker/php
volumes:
- ./application:/var/www/
links:
- mysqlserver
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69. 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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70. Let’s try that again
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71. Deploying
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72. I can’t answer this for you
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73. Questions?
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74. 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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75. 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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76. 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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77. Rancher in action
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78. Questions?
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79. http://ctankersley.com
chris@ctankersley.com
@dragonmantank
https://joind.in/talk/c1ecb
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