The document presents a comprehensive overview of Docker, a platform that allows developers and sysadmins to build, ship, and run distributed applications using containers. It explains technical aspects, tools (like Docker Hub and Docker Compose), and provides examples on how to run and manage containers, including persistent data with volumes and networking between containers. Additionally, it discusses the use of Docker Machine for provisioning and Docker Swarm for cluster management, ending with insights on deployment and application structure with Docker Compose.

1. Docker for Developers
Chris Tankersley
@dragonmantank
SunshinePHP 2016
SunshinePHP 2016 1

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
SunshinePHP 2016 2

3. Docker
SunshinePHP 2016 3

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.”
SunshinePHP 2016 4
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
SunshinePHP 2016 5

6. Containers
SunshinePHP 2016 6

7. Normal Bare-Metal Server
SunshinePHP 2016 7
CPU RAM HD Network
OperaVng System
nginx PHP DB

8. Virtual Machines
SunshinePHP 2016 8
CPU RAM HD Network
OperaVng System
nginx PHP DB
OperaVng System
nginx PHP DB
OperaVng System
Hypervisor

9. Containers
SunshinePHP 2016 9
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
SunshinePHP 2016 10

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
SunshinePHP 2016 11

12. Sorry OSX Users
• Docker support is officially maintained through Docker Toolbox
SunshinePHP 2016 12

13. Docker Toolbox also is for Windows
SunshinePHP 2016 13

14. Let’s use Docker
SunshinePHP 2016 14

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
SunshinePHP 2016 15

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
SunshinePHP 2016 16

17. Running a simple shell
SunshinePHP 2016 17

18. Running Two Webservers
SunshinePHP 2016 18

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
SunshinePHP 2016 19

20. Volumes
SunshinePHP 2016 20

21. Modifying a running container
• `docker exec` can run a command inside of an exisVng container
• Use Volumes to share data
SunshinePHP 2016 21

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
SunshinePHP 2016 22

23. Mounting from the host machine
SunshinePHP 2016 23

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
SunshinePHP 2016 24

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
SunshinePHP 2016 25

26. Mounting Data Volumes
SunshinePHP 2016 26

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
SunshinePHP 2016 27

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
SunshinePHP 2016 28

29. Network Linking
SunshinePHP 2016 29

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
SunshinePHP 2016 30

31. More Traditional Setup
SunshinePHP 2016 31
INTARWEBS Nginx PHP-FPM
Data Volume
Port 9000
Editor

32. Let’s Build It
SunshinePHP 2016 32

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
SunshinePHP 2016 33

34. Creating your own Images
SunshinePHP 2016 34

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
SunshinePHP 2016 35

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/*
SunshinePHP 2016 36

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
SunshinePHP 2016 37

38. Other Helpful Commands
SunshinePHP 2016 38

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
SunshinePHP 2016 39

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
SunshinePHP 2016 40

41. Docker Machine
SunshinePHP 2016 41

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
SunshinePHP 2016 42

43. Creating a new machine
SunshinePHP 2016 43

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
SunshinePHP 2016 44

45. Docker Swarm
SunshinePHP 2016 45

46. What is Docker Swarm?
• Cluster management tool developed by Docker
• Looks like a machine running docker, but is actually many machines
SunshinePHP 2016 46

47. Create a Swarm token
$ docker run --rm swarm create 2
//...
340122bb69c98825b4ac7094c87a07e21
SunshinePHP 2016 47

48. Create a Swarm Master
$ docker-machine create -d virtualbox
--swarm
--swarm-master
--swarm-discovery token://40122bb69c98825b4ac7094c87a07e21
swarm-master
SunshinePHP 2016 48

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
SunshinePHP 2016 49

50. Switch to the master
eval $(docker-machine env --swarm swarm-master)
SunshinePHP 2016 50

51. Add some containers
SunshinePHP 2016 51

52. Docker Compose
SunshinePHP 2016 52

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
SunshinePHP 2016 53

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
SunshinePHP 2016 54

55. Docker Compose in Action
SunshinePHP 2016 55

56. Let’s build an application
SunshinePHP 2016 56

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
SunshinePHP 2016 57

58. Folder Structure
SunshinePHP 2016 58

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
SunshinePHP 2016 59

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;
}
}
SunshinePHP 2016 60

61. Hello World
<?php
echo "Hello World";
SunshinePHP 2016 61

62. Bringing it to life
SunshinePHP 2016 62

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
SunshinePHP 2016 63

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
SunshinePHP 2016 64

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';
SunshinePHP 2016 65

66. Testing it
SunshinePHP 2016 66

67. Why didn’t it work?
• Default PHP images ship with barely any extensions enabled by
default
• We will need a custom PHP Image
SunshinePHP 2016 67

68. Update our docker-compose.yml
phpserver:
build: ./docker/php
volumes:
- ./application:/var/www/
links:
- mysqlserver
SunshinePHP 2016 68

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"]
SunshinePHP 2016 69

70. Let’s try that again
SunshinePHP 2016 70

71. Deploying
SunshinePHP 2016 71

72. I can’t answer this for you
SunshinePHP 2016 72

73. Questions?
SunshinePHP 2016 73

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?
SunshinePHP 2016 74

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
SunshinePHP 2016 75

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
SunshinePHP 2016 76

77. Rancher in action
SunshinePHP 2016 77

78. Questions?
SunshinePHP 2016 78

79. http://ctankersley.com
chris@ctankersley.com
@dragonmantank
https://joind.in/talk/c1ecb
SunshinePHP 2016 79