Dockerizing Symfony2 application. Why Docker is so cool And what is Docker? And what are Containers? How they works? What are the ecosystem of Docker? And how to dockerize your web application (can be based on Symfony2 framework)?

2. Dockerizing
Symfony2
application
Roman R.

3. Who am I?
Roman Rodomansky
itspoma@gmail.com
- Software Engineer at EPAM (more Dev than Ops)
- @founder of 2enota, and of adbar
- @co-organizer Lviv GDG
github.com/itspoma
skype: roman.rodomanskyy
linkedin.com/in/rodomansky

4. Questions
- who has tried Vagrant?
- who has tried Docker? (online tutorial)
- who has tried the real Docker? (deployed remote VM)
- Installed Docker locally? (under the boot2docker, or Vagrant)
- Who has written a Dockerfile? (and built it)
- An published image on Docker Hub?
- Deployed Docker image for stage?

5. ● why Docker is so cool (container madness)
● what is Docker (and why it matters)
● what are Containers (w/ background)
● the Docker ecosystem (w/ tools)
● dockerizing Symfony2 application workflow
Agenda

6. Docker
is a trend

12. The problems

13. The problems
- application deploy harder than could be
- application can’t run, by reason of differences in environments
- deploying machines separately from applications
- used entire operating systems to deploy (with all of the security footprint that they entail)
- heavy-weight virtualized servers without specifying CPU/memory/etc
- make a magic button to “publish app anywhere”
- container management
- different deployment mechanisms for custom nodes

14. The isolation problem
Project A: zend server, mysql, php 5.3
Project B: apache2, postresql, php 5.4, rabbitmq
Project C: apache2, mysql, php 5.6, oracle, solr, ldap

15. Hypervisor or Not?

16. vs VM
Speed:
VBox -> 1 min
docker -> 0.3 sec
Memory:
VBox -> 256 Mb
docker -> 1 Mb
Disk quota:
VBox: 1 Gb
docker: 100 kb

17. LinuX Containers
has been present in Linux kernels for 5+ years and now is considered fairly mature
others:
- lmctfy Let Me Contain That For You (Google)
- libcontainer (Docker)
Background: LXC

18. Background: namespaces
separate namespaces for containers
own mount
own net namespace (network interfaces)
own uts namespace (hostname)
own ipc namespace
own user namespace (mapping uid-s between inside/outside of)

19. Control Cgroups
is a Linux kernel feature
that limits and isolates the resource usage (CPU, memory, disk I/O, network, etc) of a collection of processes
Google engineers started work on this feature in 2006 under the name “process containers”
in 2007 changed name to “control groups”
the goal - to provide a unified interface to many different use cases
- memory
- cpu
- blkio
- devices
Background: cgroups

20. Build,
Ship,
Run
Any Application
Anywhere

21. - Build: package your application in a container
- Ship: move that container from a machine to another
- Run: execute that container
- Any application: anything that runs on Linux
- Anywhere: local VM, cloud instance, raspberry pi, baremetal...
The Idea

22. Hello, Docker. Who are you?
tool for managing LXC containers
client / hub

23. What is a Docker Container?
- high level = is a small virtual machine
- with own process space, network interface
- can run staff as root
- low level = it is a chroot on a steroids
- isolation with namespaces
- limitation by cgroups (own mount, own
- A container is a single service in a larger application
- a web server (e.g., nginx)
- an application server (e.g., PHP-FPM)
- need a database server (e.g., MySQL)
- Each of these services can be separated into its own Docker container

24. What is a Docker Image?
Imagine a Docker image
as a PHP class

25. bash$ docker search centos
https://registry.hub.docker.com/
https://registry.hub.docker.com/_/centos/
bash$ docker push # image to the Hub
bash$ docker pull # this image from any machine
is a cloud for sharing container images and automating workflows
free for public
paid for private
metadata + archives
similar to Git commits structure
What is a Docker Hub?

26. $ docker run -ti ubuntu /bin/bash
$ docker run -ti debian /bin/bash
$ docker run -ti fedora bash
$ docker run -ti centos bash
Your First Container
$ docker search centos
$ docker run --rm -ti centos:7 bash
$ docker run --rm -ti centos:6 bash
$ docker run --rm -ti centos:5 bash
root@container:/# cat /etc/issue

27. Building a Server with Dockerfile
- receipe to build a container
- start FROM a base image
- RUN commands on top of it
- easy to learn, easy to use

28. Dockerfile example
FROM ubuntu:14.04
RUN apt-get update
RUN apt-get install -y nginx
EXPOSE 80
bash$ docker build -t example/nginx .
bash$ docker run -d -P example/nginx
Stop!
Demo time
show “simple-container”
https://github.com/itspoma/docker-symfony2/tree/master/env/simple-container/

29. demo time
(single container)

30. Finally, run the web server
docker run -p 80:80 -d nginx-example
docker ps
docker run -v /home/core/share:/var/www:rw -p 80:80 -d
nginx-example
docker inspect <Container ID>

31. Linking Containers
if containers need to communicate with eachother
if your application container needs to communiate with a database container
$ docker run -p 3306:3306 -name mysql -d some-mysql-image
$ docker run -p 80:80 -link mysql:db -d some-application-image
$ env | grep MYSQL
MYSQL_PORT_3306_TCP_ADDR=172.17.0.8
MYSQL_PORT_3306_TCP_PORT=3306

32. demo time
(multiple container)

33. Docker ecosystem
Docker Engine
open-source tool, written in Go, runs as a daemon, comes with a CLI, has a REST API
Docker Hub
registry of services, public/private repos, automated builds
Docker community
> 600 contributors
~20 core mainainers
> 50k repos on Docker Hub
Docker Compose
Docker Machine
Docker Swarm

34. Docker Machine
Automatically setups up Docker
on your computer,
on cloud providers,
and inside your data center.
Can provisione any host.
bash$ docker-machine create -d virtualbox dev
bash$ docker-machine create -d digitalocean dev

35. Docker Swarm
Provides native clustering capabilities to turn a
group of Docker engines into a single, virtual Docker
Engine.

36. run your stack with one command: docker-compose up
describe your stack with one file: docker-compose.yml
# docker-compose.yml
web:
image: php:5.6-apache
links:
- db:db
volumes:
- .:/var/www/html
db:
image: postgres
Docker Compose

37. demo time
(using Compose)

38. And, push it to the stage
git clone http://github/repo.git
docker-compose up -d

39. Zero DownTime

40. attach Attach to a running container
build Build an image from a Dockerfile
commit Create a new image from a container's changes
diff Inspect changes on a container's filesystem
events Get real time events from the server
exec Run a command in a running container
images List images
history Show the history of an image
images List images
inspect Return low-level information on a container or image
port Lookup the public-facing port that is NAT-ed to PRIVATE_PORT
ps List containers
...
Making Docker commands

41. 1) The Shared Base Container(s)
2) The Shared Volume Dev Container
3) The Dev Tools Container
4) The Test In A Different Environment containers
5) The Build Container
6) The Installation Container
7) The Default-Service-In-A-Box Containers
8) The Infrastructure / Glue Containers
Docker development patterns

42. ● docker stats (built-in)
● CAdvisor (available as container, free)
● Scout (SASS, paid)
● Data Dog (SASS, free)
● Sensu (container, free)
Containers Monitoring

43. $ docker stats 18ef566e1cba 61403b48f054 e1d1e09f0dc1
CONTAINER CPU % MEM USAGE/LIMIT MEM % NET I/O
18ef566e1cba 0.44% 264.7 MiB/1.957 GiB 13.21% 1.988 KiB/648 B
61403b48f054 0.00% 684 KiB/1.957 GiB 0.03% 2.32 KiB/648 B
e1d1e09f0dc1 0.01% 17.85 MiB/1.957 GiB 0.89% 5.158 KiB/40.1 KiB
Containers Monitoring: docker stats

44. docker run
--volume=/:/rootfs:ro
--volume=/var/run:/var/run:rw
--volume=/sys:/sys:ro
--volume=/var/lib/docker/:/var/lib/docker:ro
--publish=8080:8080
--detach=true
--name=cadvisor
google/cadvisor:latest
$ open http://$(boot2docker ip):8080/
Containers Monitoring: CAdvisor

45. Resources
- Docker Cheat
Sheet https://github.com/wsargent/docker-cheat-sheet
- Docker for Developers - Jérôme Petazzoni
https://www.youtube.com/watch?v=FdkNAjjO5yQ
- https://github.com/veggiemonk/awesome-docker
Sources: https://github.com/itspoma/docker-symfony2

46. Summary
With Docker, you can:
- you fairly easily can build servers
- put your software into container
- run those containers anywhere
- write receipes to automatically build containers
- automate testing, building, hosting using the Docker Hub
Everything in the environment is under your control
ship the entire environment instead of just code!

47. The end.
Thanks!