Capistrano is an open source tool that automates deploying web applications to multiple servers. It allows deploying new versions of an application in a transactional way that can rollback changes. Capistrano handles tasks like copying code, database migrations, and restarting services. It works by creating a new release directory on servers, pulling code from a repository, and symlinking the current version. Capistrano configurations can define stages, servers, and custom tasks for deploying applications.

1. DEPLOY MADE EASY
(even on Friday)
Riccardo Bini
@odracci

2. In the beginning

4. F
A
I
L

5. DEPLOYTOOLS
• Idephix
• puppet
• fabric

6. CAPISTRANO
Capistrano is an open source tool for running scripts on
multiple servers; its main use is deploying web applications. It
automates the process of making a new version of an
application available on one or more web servers, including
supporting tasks such as changing databases.
http://en.wikipedia.org/wiki/Capistrano

7. WHY?
One-click deploy
Deploy in transaction
Rollback
Automated tasks (minifing CSS/JS, DB migrations)

8. RECIPES
Capifony http://capifony.org
Railsless-deploy https://github.com/leehambley/railsless-deploy
Multistage https://github.com/capistrano/capistrano/wiki/2.x-Multistage-Extension

9. `-- /var/www/my-app.com
|-- current ! /var/www/my-app.com/releases/20131004131539
|-- releases
| `-- 20131004131539
| `-- 20131004150741
| `-- 20131004145325
`-- shared
|-- web
| `-- uploads
`-- config
`-- config.php
HOW IT WORKS

10. HOW IT WORKS
ssh to the server (my-app.com)
• create a new release path (/var/www/my-app.com/releases/...)
• pull the latest project version from the remote git repo
• copy the source code, pulled from git, into the release path
http://capifony.org

11. HOW IT WORKS

12. $ capify .
[add] writing './Capfile'
[add] making directory './config'
[add] writing './config/deploy.rb'
[done] capified!
SETUP
$ cap deploy:setup

13. # to deploy: cap -S branch=<branchname> deploy
set :application, "set your application name here"
set :repository, "git@github.com:odracci/#{application}.git"
set :scm, :git
server "my-app.com", :app, :web, :db, :primary => true
set :deploy_to, "/var/www/my-app.com"
set :branch, fetch(:branch, "master")
set :shared_children, ["web/uploads", "config"]
set :user, "vagrant"
set :group_writable, true
set :use_sudo, false
set :copy_exclude, [".git"]
set :deploy_via, :remote_cache
set :keep_releases, 5
ssh_options[:forward_agent] = true
default_run_options[:pty] = true
logger.level = Logger::MAX_LEVEL
# if you want to clean up old releases on each deploy uncomment this:
after "deploy:restart", "deploy:cleanup"
config/deploy.rb

14. $ cap <env> deploy
server "www.my-app.com", :app, :web, :db, :primary => true
set :deploy_to, "/var/www/my-app.com"
set :branch, fetch(:branch, "master")
MULTISTAGE
server "s.my-app.com", :app, :web, :db, :primary => true
set :deploy_to, "/var/www/my-app.com"
set :branch, fetch(:branch, "develop")
config/deploy/production.rb
config/deploy/staging.rb
command line

15. cap deploy # Deploys your project.
cap deploy:check # Test deployment dependencies.
cap deploy:cleanup # Clean up old releases.
cap deploy:cold # Deploys and starts a `cold' application.
cap deploy:create_symlink # Updates the symlink to the most recently deployed...
cap deploy:migrate # Run the migrate rake task.
cap deploy:migrations # Deploy and run pending migrations.
cap deploy:pending # Displays the commits since your last deploy.
cap deploy:pending:diff # Displays the `diff' since your last deploy.
cap deploy:restart # Blank task exists as a hook into which to install...
cap deploy:rollback # Rolls back to a previous version and restarts.
cap deploy:rollback:code # Rolls back to the previously deployed version.
cap deploy:setup # Prepares one or more servers for deployment.
cap deploy:start # Blank task exists as a hook into which to install...
cap deploy:stop # Blank task exists as a hook into which to install...
cap deploy:symlink # Deprecated API.
cap deploy:update # Copies your project and updates the symlink.
cap deploy:update_code # Copies your project to the remote servers.
cap deploy:upload # Copy files to the currently deployed version.
cap invoke # Invoke a single command on the remote servers.
cap shell # Begin an interactive Capistrano session.
cap -T

16. namespace :deploy do
task :start do
end
task :stop do
end
task :restart, :roles => :app, :except => { :no_release => true } do
run "sudo /etc/init.d/httpd restart"
end
end
OverrideTasks

17. namespace :config do
desc "Upload config/config.php to remote server"
task :to_remote do
upload("config/config.php", "#{shared_path}/config/config.php", :via => :scp)
end
end
$ cap config:to_remote
CustomTasks

18. WTF

19. [my-app.com] executing command
** [my-app.com :: out] Permission denied (publickey).
** [my-app.com :: out]
** [my-app.com :: out] fatal: The remote end hung up unexpectedly
** [my-app.com :: out]
command finished in 2769ms
*** [deploy:update_code] rolling back
WTF
$ ssh-add

20. namespace :deploy do
desc 'Show deployed revision'
task :revision, :roles => :app do
run "#{try_sudo} cat #{current_path}/REVISION"
end
end
WTF
$ cap deploy:revision

21. #server "server1, :app, :web, :db, :primary => true
role :app, "server1", "server2"
role :web, "server1", "server2"
role :db, "dbserver", :primary => true
SCALING WEB APPS
$ cap deploy:setup

22. THANKS
Riccardo Bini
@odracci
github.com/odracci

23. QUESTIONS?