Learn how to use Capistrano to automate the deployment of your Ruby on Rails applications. Apply best practices and add-ons for customizing Capistrano.

1. Getting Started
with Capistrano
and Ruby on Rails

2. Automated App
Deployment
using ssh

3. Not for server
configuration
Use Chef or Puppet for that

4. Installation
$ gem install capistrano
Bundler:
gem „capistrano‟

5. Capify your application
$ capify .

6. Rails Directory Structure
/
|- public/
|- config/
- deploy.rb <--- Capistrano
|- application/

7. Example Script
set :application, "set your application name here”
role :app, "your app-server here”
role :web, "your web-server here”
role :db, "your db-server here", :primary => true

8. Example Script (git)
set :scm, :git
set :repository, “username@hostname:myapp.git”
set :branch, “master”
set :deploy_via, :remote_cache

9. Example Script
(Passenger)
namespace :deploy do
desc "Restarting mod_rails with restart.txt”
task :restart, :roles => :app, :except => { :no_release => true } do
run "touch #{current_path}/tmp/restart.txt”
end
[:start, :stop].each do |t|
desc "#{t} task is a no-op with mod_rails”
task t, :roles => :app do ; end
end
end

10. Example Script (mongrel)
require 'mongrel_cluster/recipes'
namespace :deploy do
task :restart do
restart_mongrel_cluster
end
end

11. First-time server setup
$ cap deploy:setup

12. :deploy_to/
|- releases/
- 201205041112
- 201206110904
|- current/ --> 201206110904

13. Deploy the app
$ cap deploy

14. Deploy and run
migrations
cap deploy:migrations

16. Rollback to the last
version
$ cap rollback

17. Capistrano Best
Practices

18. 1. Create Deploy User
$ sudo useradd deploy
(helps scope gems, config, logs, etc.)

19. 2. Cleanup Old Deploys
$ cap cleanup
(leaves last 5 deploys, removes the rest)

20. 3. Multi-Stage Deploy
$ gem install capistrano-ext
Bundler:
gem „capistrano-ext‟

21. config/deploy.rb:
set :stages, %w(production staging)
set :default_stage, "staging”
require 'capistrano/ext/multistage‟
Add users for each stage:
$ sudo useradd staging
$ sudo useradd production

22. 4. Disable sudo
config/deploy.rb:
:use_sudo false

23. 5. Colorize Capistrano
$ gem install capistrano_colors
In config/deploy.rb:
require 'capistrano_colors'

25. Thank you
@launchany
james@launchany.com
http://launchany.com