Ruby and on Rails

Muriel SalvanX-Aeon SolutionsFeb 04th 2014Riviera.rb

Who am I?

Muriel SalvanFreelance DeveloperFounder of X-Aeon SolutionsOpen Source advocateRuby / Rails expertCo-founder of RivieraRB

@MurielSalvanGithubSourceForgeMy tech blogMuriel@X-Aeon.com

Let's talk about cargo transport(that's why you came here, right?)

"I want my piano to be delivered from Nice to London"

"I also want my barrel of wine delivered from Nice to London."

"Hey! Don't forget my bags of rice too!"

How ?

"By train, plane, boat, truck, bus, mule, or whatever!"

Do I worry about how goods interact (e.g. coffee beans next to spices)Can I transport quickly and smoothly(e.g. from boat to train to truck)

A standard container that is loaded with virtually any goods, and stays sealed until it reaches final delivery.

in between, can be loaded and unloaded, stacked, transported efficiently over long distances, and transferred from one mode of transport to another

Static websiteWeb frontend User DBQueueAnalytics DBBackground workersAPI endpointDevelopment VMQA serverPublic CloudDisaster recoveryContributors laptopProduction ServersProduction Cluster

Customer Data Center

Do services and apps interact appropriately?Can I migrate smoothly and quickly?

Static websiteWeb frontend User DBQueueAnalytics DBBackground workersAPI endpointDevelopment VMQA serverPublic CloudDisaster recoveryContributors laptopProduction ServersProduction Cluster

Customer Data Center

So what does Docker bring?

1- File systems images

Structured in layers (storing diffs only)

Layers are reused between images

Clever!

2- Processes run in a contained environment (containers)

Using images' file systems

(isolated like in chroot) In a separate process space

(using Linux containers) With a specific network interface

Can run as root

It's chroot on steroids!

3- A public repository of images

Pull and push images

Build them from Github projects

Be part of a great community!

"Is it a yet-another-virtualization-solution?"

No.

Processes run by Docker share the host Kernel

No device emulation

No boot sequence

Architectures and platforms between Host and containers must match

"So where is the portability?"

Containers can be run on any Kernel (>= 3.8, Linux 64b only for now)

Whatever the Linux distro

If it runs on the Host, it can run from a container

Physical, virtual, cloud...

It's blazingly fast!!!A few ms to load the container and run the command

Use cases

Get running clusters on a single host

Awesome to test them!

Ensure the environment your process runs in is the same in dev, test and prod

Bring your environment along with your process.Sandboxes everywhere!You'll love that!

Deployments become sooo easy

Like "push"-and-"pull"-easy!

Lightweight virtualization too

"How do we create images?"

Docker files

Describe commands to be run to create an image

# Nginx## VERSION 0.0.1

FROM ubuntuMAINTAINER Guillaume J. Charmes

# make sure the package repository is up to dateRUN echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.listRUN apt-get update

RUN apt-get install -y inotify-tools nginx apache2 openssh-server

docker build .

Docker fileImage

"And how do we run a process in a container?"

docker run

ImageContainerrunning

"I want to create a modified image"

docker commit

ImageContainer

"Hey! I want to deploy my image for the world to see!"

docker push

ImageRegistryDefaults tohttp://index.docker.io

"And now my friend wants to get my wonderful image to play with!"

Yeah, sure... whatever

docker search docker pull

ImageRegistry

"Wasn't that supposed to be a Ruby meetup?"

Let's simulate a Rails cluster with a balancing Ruby proxy in front!

Docker containerB

Docker containerB

Docker containerB

Docker containerB

Docker containerB

Docker containerA3000

3000

3000

3000

3000

5000

5001

5002

5003

5004

3000

1. Create a Ruby image: murielsalvan/ruby

From ubuntu base image

Using a Dockerfile

Bonus: Upload it to index.docker.io via Github

# Ruby environment## VERSION 0.2

FROM ubuntuMAINTAINER Muriel Salvan

RUN echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.listRUN apt-get updateRUN apt-get upgrade -y

RUN apt-get install -y build-essential zlib1g-dev libssl-dev libreadline6-dev libyaml-dev

ADD http://cache.ruby-lang.org/pub/ruby/2.1/ruby-2.1.0.tar.gz /tmp/

RUN cd /tmp && \ tar -xzf ruby-2.1.0.tar.gz && \ cd ruby-2.1.0 && \ ./configure && \ make && \ make install && \ cd .. && \ rm -rf ruby-2.1.0 && \ rm -f ruby-2.1.0.tar.gz

2. Create a Rails server image: murielsalvan/server

From murielsalvan/ruby base image

Using an interactive bash in a container to install and configure the Rails application

Add a startup command: rails s

Open default port 3000

3. Launch n docker containers from murielsalvan/server

Map each container port 3000 to host ports 5000+i

4. Create a new image for the Ruby proxy: murielsalvan/proxy

Based on murielsalvan/ruby

Using an interactive bash to install and use em-proxy, targetting servers on ports 5000+i

Add a startup command: ruby -w balancing.rb

Open port 3000

5. Launch 1 docker container from murielsalvan/proxy

Map its guest port 3000 to host port 3000

6. Target localhost:3000

7. Profit!

Sponsored by theWTF effect!

The Linux container memory is always the same whatever the process in the container:1,5MB RSS and 32MB VSZ

NOT BAD

Links

HomepageIndex of Docker imagesDockerfile referenceGetting started

This presentation is available under CC-BY license by Muriel Salvan

Source: xkcd

That's all, folks!

Thanks for attending!

Elapsed time (s) on Fibonacci computationWithout DockerWith Docker

Execution time45.792896932666738.0897856636667

Launch time0.1644531706666612.712914481

Memory consumption per container (kB)RSSVSZ

Rails60000155268

Linux container150432284

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