This document provides an introduction to Docker, including: - A brief history of container technologies leading to the development of Docker in 2013. - An overview of the Docker ecosystem and how Docker compares to virtual machines. - Common Docker commands for interacting with the Docker Engine to run, stop, inspect and manage containers. - How to build Docker images using Dockerfiles to automate the image creation process. - How Docker Compose can be used to manage multiple containers through a YAML configuration file. - Some advantages and disadvantages of using Docker for application deployment.

1. Docker 101
Denis - Florin Rendler
December 14th, 2016
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Denis – Florin RENDLER
Symfony/Magento Developer
@Evozon since 2013
Interested in PHP, DevOps and Security

3. Agenda
• Very short introduction on what Docker is
• Rundown of useful Docker CLI commands
• Overview of what we need to build a Docker
image
• Manage containers in a “one service per
container” architecture
• Q&A
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5. Container Technology History
• 1979: Unix V7 introduces `chroot`
• 2000: FreeBSD Jails
• 2001: Linux vServer
• 2004: Oracle Solaris Containers
• 2005: Open VZ (Open Virtuzzo)
• 2006: Process Containers
• 2008: LXC
• 2013: Docker project is made public
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6. Docker Ecosystem
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Docker Compose
Docker Machine
Docker Engine
Docker Swarm

7. Virtual Machines vs Docker
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Using
Hyper-V on Windows 10 PRO
And WindowsContainers
on Win Server 2016
Using xhyve Virtualization
Docker Supported OS
Using native
container technologies

9. LET’S TAKE DOCKER FOR A SPIN
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10. Docker Engine
• We interact with Docker Engine through the
`docker` command
• 40+ sub-commands including create, run, top,
logs, deploy, diff etc.
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11. Common Docker Commands
• docker run [image_name]
• docker start [container_id]
• docker stop [container_id]
• docker ps
• docker exec --ti [container_id] bash
• docker inspect [container_id]
• docker top [container_id]
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12. Docker Data Volumes
• Data volumes are Docker’s way for sharing data
• Data Volumes are initialized when a container is
created
• Data volumes can be shared and reused among
containers
• Changes to a data volume are made directly
• Changes to a data volume will not be included when
you update an image
• Data volumes persist even if the container itself is
deleted
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13. Networking Docker Containers
• Map communication ports between container
and host
• Isolate containers into network groups
• Use host names instead of IPs to connect
between containers using Docker’s built-in
DNS provider
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14. BUILDING A DOCKER IMAGE
Creating the project’s “gold master” image
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15. Images && Containers
• An “image” is a filesystem and parameters to
use at runtime. It doesn’t have state and
never changes.
• A container is a running instance of an image.
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16. Dockerfile
• An automation script file containing
instructions on how to build the image
• Allows you to configure steps for installing
software, configure software or copy file from
host
• Allows you to specify image metadata and
external config options
• Each command creates a snapshot
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17. Working With Images
• docker images
• docker pull/push [image_name]
• docker rmi [image_name/image_id]
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18. Dockerfile In Review
• The only required command is “FROM image”
• Group commands together to avoid unnecessary
caching
• The build/execution context is the Dockerfile’s
path
• “EXPOSE” is mostly informative
• “VOLUMES” creates a random volume on host
• Add a “CMD” or “ENTRYPOINT” command when
using base images
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19. CONTAINER MANAGEMENT WITH
DOCKER-COMPOSE
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20. docker-compose.yml
• YAML based definition file for declaring
services, netwoks and data volumes
• Dockerfile builds images and docker-
compose.yml manages containers
• Docker-Compose uses file composition for
service definitions
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21. Disadvantages
• Kernel dependency
• Drive space
• Limited number of management tools for
production deployments
• Data needs to be stored outside containers
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22. Advantages
• Solves the “It worked on my machine!”
situation
• Consistent environment for your application
• Version control and component reuse
• Application isolation
• Quick component swapping
• Portability across machines
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23. Q&A Time
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24. Resources
• http://blog.aquasec.com/a-brief-history-of-
containers-from-1970s-chroot-to-docker-2016
• https://docs.docker.com/
• https://github.com/rendler-denis/docker-app-
skeleton
• https://www.upguard.com/articles/docker-vs-
lxc
• https://www.phproundtable.com/episode/do
cker-and-php
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Thank you for attending.