Advanced Deployment with Rails
JAX 2009
Jonathan Weiss, 21 April 2009
Peritor GmbH

Who am I?
Jonathan Weiss
• Consultant for Peritor GmbH in Berlin
• Specialized in Rails, Scaling, Deployment, and Code Review
• Webistrano - Rails deployment tool
• FreeBSD Rubygems and Ruby on Rails maintainer
http://www.peritor.com
http://blog.innerewut.de
http://twitter.com/jweiss
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Advanced Deployment
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Advanced Deployment
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Deployment
Deployment
Architecture Process
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Infrastructure
Architecture
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Simple Rails Setup
One Rails instance handles all requests
Rails is (was) single-threaded: There is only one concurrent request
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Rails Setup
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Rails Setup
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Typical Rails Setup
• A load-balancer distributes the incoming requests
• Some load-balancers will deliver static requests themselves
• Several Rails instances handle all requests
• Number of concurrent requests equals number of Rails instances
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Rails Setup Options
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Deployment Questions
Apache? Pound?
mod_proxy_balancer?
FastCGI?
Mongrel?
Proxy? Load-balancer?
Nginx?
mod_rails?
Ebb?
HA-Proxy? Reverse Proxy?
Swiftiply?
Phusion Passenger?
Thin?
Pen?
Rails Application
Lighttpd?
Server?
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The relevant ones
Rails Application Server Proxy/Web Server
• Mongrel • Apache2
• mod_rails / Phussion Passenger • Nginx
• JRuby + Glassfish & Co. • HA-Proxy
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Mongrel
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Mongrel
• Complete HTTP-Server that can load arbitrary Ruby-servlets
• Built-in Rails support
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Mongrel
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Mongrel
Apache 2.2 – mod_proxy_balancer
Lighttpd
Nginx
HA-Proxy
Pound
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Mongrel Cluster
Utility to manage several Mongrel instances
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Mongrel Cluster
Control Mongrels
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Mongrel
• Very robust
• Strict HTTP parser
• Easy to debug (HTTP!)
• Defacto standard deployment with Apache 2.2 and mod_proxy_balancer
• Can be a bit difficult to setup (mongrel_cluster, ports, Apache)
• Not so easy on mass/virtual hosting
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mod_rails
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mod_rails a.k.a Phusion Passenger
• Module for Apache 2.2 (and Nginx)
• Allows Apache to control Rails instances
• Apache starts and stops application instances depending on the application load
• Able to run any RACK-compatible Ruby application (Merb & Co.)
• Only manages Rails on one host - no remote instances
• Combine with HTTP-Proxy / balancing solution
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Install Phusion Passenger
Install module
Load and activate in Apache
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Control Phusion Passenger
Restart after deployment:
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Phusion Passenger
One machine
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Phusion Passenger
One machine Multiple machines
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Phusion Passenger
• Fairly new but ready for production
• Makes setup easier – on the single machine level
• Multiple servers still require load balancer
• Suitable for mass-hosting
• (upcoming) standard way of deploying Rails
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JRuby
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• Ruby Runtime on the Java Virtual Machine
• Implemented in Java and Ruby
• Compiles Ruby into Java-bytecode
• Integrates with Java code and libraries
• Java’s promises of native threads and JIT
• Allows for Ruby/Rails applications to be packaged as WAR files
• WAR files deployable on any J2EE-container:
Glassfish, JBoss, Tomcat, Jetty, …
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JRuby on Rails
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JRuby on Glassfish
One machine
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JRuby on Glassfish
One machine Multiple machines
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Setup JRuby on Glassfish
1. Download JRuby and Glassfish
2. From http://blog.headius.com/2008/08/zero-to-production-in-15-minutes.html
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Warble Configuration
Define min/max
Rails runtimes
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Infrastructure
Process
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Deployment Process Requirements
Reproducible Accountable Notifications
Automatic
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Deployment Options
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Deployment Options
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Deployment Options
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Deployment Options
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What does Capistrano do?
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Capistrano Deployment Cycle
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The Deployment Lifecycle
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Requirements
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Get Your Capistrano On
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Get Your Capistrano On
config/deploy.rb
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Capistrano
Your one-stop deployment shop
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Capistrano Tasks
To find all the tasks available in your project, use
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Custom Tasks
Override build-in
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Write your own Tasks
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Write your own Tasks
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The Rest
• Callbacks
• Transactions
• Capistrano Shell
• Custom tasks and namespaces
• Staging and multiple setups
• Gem dependencies
• Support for deploying through gateway servers
• Server setup with deprec gem
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One Click Deploy
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Webistrano
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Webistrano
• Web-UI to Capistrano
• Manages projects and their stages
• Alerting and Accounting
• Scriptable and extendable
• BSD License
http://labs.peritor.com/webistrano
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Macistrano
• Mac-GUI to Webistrano
• Fire and monitor deployments from your desktop
http://github.com/mattmatt/macistrano
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Cloud Infrastructure
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Cloud Infrastructure
Servers come and go
• You do not know your servers before deploying
• Restarting is the same as introducing a new machine
You can’t hardcode IPs
database.yml
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Solution #1
Query and manually adjust
• Servers do not change that often
• New nodes probably need manual intervention
• Use AWS ElasticIPs to ease the pain
Set servers dynamically AWS Elastic IP
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Solution #2
Use a central directory service
• A central place to manage your running instances
• Instances query the directory and react
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Solution #2
Use a central directory service
• A central place to manage your running instances
• Instances query the directory and react
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Central Directory
Different Implementations
• File on S3
• SimpleDB
• A complete service,
capable of monitoring and controlling your instances
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Final words
Once understood the Rails infrastructure is quite simple
Passenger is very easy to setup and should be the default choice
Learn how to use Capistrano and Webistrano,
they will make your life much easier – even in non-Rails setups
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Questions?
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Peritor GmbH
Teutonenstraße 16
14129 Berlin
Telefon: +49 (0)30 69 20 09 84 0
Telefax: +49 (0)30 69 20 09 84 9
Internet: www.peritor.com
E-Mail: kontakt@peritor.com
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