Real WorldRails Deployment

Alan Hecht

Deployment Options

• Heroku - PaaS

• Shared Web Hosting

• Virtual Private Server

• Amazon Web Services - IaaS

Heroku - PaaS

• No setup & no system administration- Easy to deploy

• Free when using one web process- Pay as you scale

• App will idle after inactivity if only using one process (“dyno”)

• Additional “dyno” + database > 5MB is $50/month

Shared Web Hosting

• Cheap - $5 to $10 per month

• Web hosting control panel (i.e. cPanel) to configure web server & web application

• Limited to what is on the server

• Not recommended- Constrained by CPU usage

Virtual Private Server

• Starts at around $25 per month

• Extremely flexible, can load anything you want

• System administration knowledge required- Must maintain server

• Good for one or two standalone servers

Amazon Web Services - IaaS

• Building a virtual data center• Netflix runs on AWS

• Can load instances with a pre-built O/S

• Pay as you scale

• Most expensive option

Running Rails

• WEBrick should only be used in a development environment

• Need a web server to handle static requests- Images, HTML, JavaScript, CSS

• Need a Ruby web application server to handle Rails requests (i.e. Unicorn, Thin, or Passenger)

Web Server

• Apache & Nginx the two most popular choices

• Rack is used as an interface between the web server and Rails

Apache

• Most popular web server and has the many options & features

• Process-based web server

• Good for handling dynamic content via modules

Nginx

• Light weight web server that only handles static content

• Event-based web server

• Low memory usage

Apache or Nginx

• Pick one - either works

• Nginx better on a VPS because of low memory usage

• Apache is full-featured

• Nginx does a few things well

Rails Web App Servers

• Phusion Passenger, Thin, and Unicorn currently the most widely used Rails app servers

• Can be installed as a web server plugin or as a separate Ruby Gem

Phusion Passenger

• Acts as an Apache or Nginx module

• Philosophy – same as Rails (DRY, convention over configuration)

• Easy to deploy & maintain- No separate configuration file

Thin

• Event based Rails server

• Philosophy – tiny, fast, and secure

• Used by Heroku

Unicorn

• Process-based Rails server

• Philosophy – Unicorn is Unix

• Used by Twitter & GitHub

Nginx + Unicorn Architecture

Sample Nginx Configuration

Which One?

• People have built scalable sites with all three

• Thin & Unicorn need configuration, Passenger does not

• Performance depends on the application- “Hello World” apps not useful for profiling

Capistrano

•Tool for deploying Rails (or Rack) applications

•Similar in structure to Rakefile

Sample Capistrano Script

What Does a Scalable Site Architecture Look Like?

Content Delivery Network

Nginx SSL

HA Proxy

Nginx +Unicorn

Nginx +Unicorn

Nginx +Unicorn