Guided Exploration
Deploying Rails apps with Chef and Capistrano
Dan Ivovich
BohConf Baltimore 2013
7/19/2013

Dan Ivovich
http://smartlogic.io
Twitter - @danivovich
Dan Ivovich on GitHub
Director, Development Operations
SmartLogic

What is the goal?
● Build a machine that can run the application
● Do so quickly and repeatedly
● Make deploying the app, upgrading
components, adding components, etc seamless
and easy

How?
● Chef - Infrastructure Management
● Capistrano - Application Deployment

Who does what?
● Chef
○ Users / SSH Keys
○ Web server
○ Database
○ Postfix
○ Redis / Memcached
○ Monit
○ NewRelic Server monitoring
○ /etc/hosts
○ rbenv & Ruby
○ Binary dependencies (e.g. Sphinx)

Who does what?
● Capistrano
○ Virtual Hosts
○ Unicorn init.d script
○ Unicorn.rb
○ Monit process monitors
○ Normal Capistrano Stuff

Why both?
● Use each for what it is best at
● Chef is for infrastructure
● Capistrano is for the app
● Could have more than one Capistrano app with
the same Chef config
● Chef config changes infrequently, Capistrano
config could change more frequently

How? - Chef
● Standard Recipes
● Custom Recipes
● Recipes assigned to Roles
● Roles assigned to Nodes
● Nodes with attributes to tailor the install

How? - Capistrano
● Standard Tasks
● Custom Tasks
● Templating files

To The Code!

git clone git@github.com:smartlogic/chef-cap-
demo.git
See the README or follow along the following git tags

git checkout rails_app

Basic Rails Application
1. Displays some data from a database, includes a
rake task to add some data to the database
2. No deployment code of any kind at this point

git checkout meet_the_chef

Basic Chef Configuration
1. Web Server
2. Database Server
3. Dependencies
4. Nothing application specific

git checkout app_cookbook

Application Cookbook
1. User account to run the application as
2. Folder structure to store the application
3. Application specific dependencies
4. rbenv
5. The application database

git checkout cap_setup

Capistrano Setup
1. Virtual hosts configuration
2. Unicorn configuration
3. Monit configuration
4. Application setup (linking database.yml)

git checkout cap_data

Capistrano Tasks
1. Simple to expose your rake tasks as capistrano
tasks
2. This task helps us see the impact of running a deploy
3. Easy to insert into the capistrano execution chain

From the top!

Ready?!? Here we go!
1. vagrant destroy
2. vagrant up
3. bundle exec knife bootstrap -p 2222 -x vagrant
-d precise32_vagrant chef_cap_demo
4. bundle exec knife cook
vagrant@chef_cap_demo
5. cap staging deploy:setup deploy:migrations

Thoughts....
● Vagrant and VMs are you friend. Rinse and repeat
● It is ok to tweak your Chef stuff and re-cook, but I always
like to restart with a fresh VM once I think I'm done
● Capistrano tweaks should be easy to apply, especially with
tasks like nginx:setup, unicorn:setup etc.
● Chef issues are harder to debug and more frustrating than
Capistrano issues, another reason to put more app specific
custom stuff in Capistrano and do standard things in Chef

Questions?
http://smartlogic.io
http://twitter.com/smartlogic
http://github.com/smartlogic
http://fb.me/smartlogic