Docker.io for Developers

What are these crazy containers you speak of?

Who am I?

Dennis Reams

Crusty Ole Developer

I'm learning Docker, just like the rest of the world.
Showing you why Docker interests me, a developer.
Interested in what you think and have learned about Docker too.
Bottom Line: Don't be afraid to contribute to this session, I need all the help I can get.

What am I doing up here?

Agenda

Basics of Docker
Docker Lifecycle
Docker In Action (Demo Time)

Dockerfile
Demo App

Reference Material

Basics of Docker

From Docker: Docker is an open platform for developers and sysadmins to build, ship, and run distributed applications. Consisting of Docker Engine, a portable, lightweight runtime and packaging tool, and Docker Hub, a cloud service for sharing applications and automating workflows

From Wikipedi: Docker uses resource isolation features of the Linux kernel such as cgroups and kernel namespaces to allow independent "containers" to run within a single Linux instance, avoiding the overhead of starting virtual machines

From Me: One BIG A$$ closure.

Definition of Terms

Virtual Machine (VM)
- emulation of a computer system
- full OS must be installed on each instance
Image (aka Virtual Machine Image)
- file consisting of a pre-configured OS and a single application.
Container (aka LinuX Container(LXC))
- OS level virtualization for running multiple isolated Linux systems from a single host

Layman's terms please...

Docker Engine
- A container hosting service that allows one to many containerized apps to run on a single OS by leveraging LXC
Docker Hub
- Cloud based virtual image repository
- Think maven repo or cdn.js for virtual machines
- Access to official/supported images as well as crowdsourced contributions.

Container Lifecycle

Pull container image (from Docker Hub)
Build a container image
Run a container image
Start/Stop a container image
Push container image (to Docker Hub)
Remove a container/image

Docker Essentials

docker ps
- list any running containers
docker ps -a
- list any containers
docker logs -f {ur container id here}
- display STDOUT & STDERR for a container
docker rm {ur container id here}
- remove a stopped container
docker rmi {ur image tag id}
- remove old images from your local machine

Docker Parameters

docker -i
- interactive mode - comm via command line
docker -d
- detached mode - comm via network connection.
docker -v
- set data volumes in the container
docker --volume-from {container name}
- allows hosting data volumes on another container.
docker --link {container name}
- establishes communication between two containers.

Stop... Demo Time

DockerFile

Coding my environment set up

Demo Application

Swapping Datasources
Resetting Stateful Data

What's Next?

Continuous Integration
- Automate this stuff!
Off loading work to other containers
- Logging
- Minecraft example - "The cool stuff"
Containers as Content Management System
How do you scale all this?

Reference Materials

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Contact Info:
Dennis Reams
Twitter: @dennis77pr

Slides @ slides.com

Code @ GitHub