This document provides an introduction to Docker, an open-source tool that allows developers to build and ship applications and services in a portable and standardized unit called a container. It discusses how Docker uses namespaces and cgroups for process isolation and resource management to run containers independently on a single machine. It also describes how Docker images are read-only layers that build upon one another, how the Docker registry stores image metadata, and how Docker allows building applications once that can run anywhere.

1. An Introduction to Docker
March 18, 2014
Vancouver Docker Meetup
Matthew Fisher, Fishworks
Reza Sanaie, Beanworks

2. Table of Contents
● Background
● Namespaces and cgroups
● Docker Images
● Docker Registry
● Docker Tutorial
● Sponsors
● Questions?

8. Why should I care?
For Developers: Build once...run anywhere
For Devops: Configure once...run anything

9. Background
● introduced at PyCon 2013
● huge community (10,000 stars and counting)
● open-source (Apache v2 licensed)
● packs, ships and runs processes
● processes are isolated in “containers”
● saves file system state as “images”
● HUGE win for automation and deployments
○ Dockerfiles, private/public registry, orchestration etc.
○ Run once, deploy anywhere

10. Namespaces and cgroups
● similar to chroot jails
● process-level virtualization (NOT a VM)
● relies on cgroups for resource limitation
○ CPU
○ memory
○ disk I/O

12. Docker Images
● read-only layer
● layers built upon layers
● images do not have state

13. Docker Registry
● public and private registry
● built in python
● stores image metadata as JSON
{
"id": "17dc5272a1edcf3172476c991ac6b5afd4c14bdf1b6ef361c9decec290dba728",
"parent": "87acc693630cd175ad518b5cdecb800430ada5895b62ff7b4bdbdf4f87f88b30",
"created": "2014-03-14T02:59:14.572378183Z",
"Cmd": null,
"Volumes": null,
…
}

15. Sponsors
● Docker Inc.
● OpDemand
● Hootsuite

16. Questions?