How to link chef with capistrano for deployment - deployment

Question

I have configured chef environment and i am able to deploy my application using capistrano . Now i want to my chef to handle capistrano to deploy my apps . How can it be done ?

Answer 1

I do the opposite, ie. deploy my Chef recipes via Capistrano. I recommend it.
#config/deploy.rb
...
before 'bundle:install', "provision:default", "deploy:config_db_yml_symlink"
...
This will execute the chef config for a server after before bundle install, which is important because a lot of gems rely on packages being installed to the OS.
#config/deploy/provision.rb
Capistrano::Configuration.instance(:must_exist).load do
namespace :provision do
task :default do
provision.setup
provision.web
provision.db
provision.db_slave
end
task :setup, once: true do
provision.get_environment_variables
provision.update_cookbooks
end
task :db, :roles => :db do
next if find_servers_for_task(current_task).empty?
if rails_env == 'staging'
run %{cd #{release_path}/provision; sudo chef-solo -c solo.rb -j db.json -l debug}
else
run %{cd #{release_path}/provision; sudo chef-solo -c solo.rb -j db_master.json -l debug}
end
end
task :db_slave, :roles => :db_slave do
next if find_servers_for_task(current_task).empty?
run %{cd #{release_path}/provision; sudo chef-solo -c solo.rb -j db_slave.json -l debug}
end
task :web, :roles => :web do
next if find_servers_for_task(current_task).empty?
run %{cd #{release_path}/provision; sudo chef-solo -c solo.rb -j web.json -l debug}
end
task :get_environment_variables do
run "if [ -d ~/.config ]; then " +
"cd ~/.config && git fetch && git reset origin/master --hard; " +
"else git clone git#github.com:mycompany/config.git .config; fi"
run "sudo cp ~/.config/secureshare/#{rails_env}/environment /etc/environment"
end
task :update_cookbooks do
run "if [ -d /u/chef ]; then " +
"cd /u/chef && git fetch && git reset origin/master --hard; " +
"else git clone git#github.com:mycompany/chef.git /u/chef; fi"
end
end
namespace :deploy do
task :setup, :except => { :no_release => true } do
dirs = [deploy_to, releases_path, shared_path]
dirs += shared_children.map { |d| File.join(shared_path, d.split('/').last) }
dirs += [File.join(shared_path, 'sockets')]
run "#{try_sudo} mkdir -p #{dirs.join(' ')}"
run "#{try_sudo} chmod g+w #{dirs.join(' ')}" if fetch(:group_writable, true)
run "#{try_sudo} chown -R ubuntu:ubuntu #{dirs.join(' ')}" if fetch(:group_writable, true)
end
task :config_db_yml_symlink do
run "ln -s #{shared_path}/database.yml #{release_path}/config/database.yml"
end
end
end
I have a folder in my project named provision, to handle the definition of chef roles, though the recipes are in a different repository.
#provision/solo.rb
root = File.absolute_path(File.dirname(__FILE__))
cookbook_path '/u/chef'
role_path root + "/roles"
log_level :debug
log_location STDOUT
Nodes are defined in the project
#provision/db_slave.json
{
"run_list": ["role[db_slave]"]
}
And roles
#provision/roles/db_slave.rb
name "db_slave"
description 'A postgresql slave.'
run_list(["recipe[base]", "recipe[postgresql::slave]", "recipe[rails]","recipe[papertrail]", "recipe[fail2ban]"])
override_attributes(
'kernel' => {
'shmmax' => ENV['KERNEL_SHMMAX'],
'shmall' => ENV['KERNEL_SHMALL'],
'msgmax' => ENV['KERNEL_MSGMAX'],
'msgmnb' => ENV['KERNEL_MSGMNB']
},
'postgresql' => {
'user' => ENV['PG_USER'],
'password' => ENV['PG_PASSWORD'],
'database' => ENV['PG_DATABASE'],
'master_host' => ENV['PG_HOST']
},
'app_dir' => ENV['APP_DIR'],
'papertrail' => {
'port' => ENV['PAPERTRAIL_PORT'],
'log_files' => [
"#{ENV['APP_DIR']}/shared/log/*.log",
"/var/log/*.log",
"/var/log/syslog",
"/var/log/upstart/*.log",
"/var/log/postgresql/*.log"
]
},
'new_relic' => {
'key' => ENV['NEW_RELIC_LICENSE_KEY']
})
All without keeping any sensitive information within the app. I also use capistrano-ec2group in order to map servers to roles using EC2 security groups.
group :myapp_web, :web
group :myapp_web, :app
group :myapp_db, :db, :primary=>true
group :myapp_db_slave, :db_slave
So basically you keep your chef recipes in one repo, your environment variables in another repo, and your app in another repo - and use Capistrano to both provision servers and deploy your app.
You could also keep your chef recipes in your application repo, but that inhibits reuse between project. The key is to put everything that changes into environment variables and store them separate to the app and the recipes.
When this is configured correctly, to add new servers you simply need to spin one up in EC2, apply the desired security group and then
cap deploy

Answer 2

You could watch that Foodfightshow Episode about Application Deployment.
You can e.g. put the configuration files (with e.g. the database credentials) to the server with Chef, while pushing the source code with Capistrano.

Answer 3

You can't. Or at least it won't be very straightforward.
Chef is a pull system -- the client pulls information from the Chef server, and takes action upon it.
Capistrano is a push system -- you tell it to log into the server and perform tasks there.
The only way I see for you to integrate them would be to run Capistrano locally on each machine, but I fail to see a reason for that.
Chef's deploy resource can probably do everything you need without the need to have Capistrano integrated. If you still want to push your deploys to the servers independently from the chef-client runs, you're better off not deploying via Chef and keeping your current system.
If you want continuous delivery, hook up your Capistrano scripts to your CI server and run them at the end of your pipeline.
The podcast referred by #StephenKing is a great source of information on this matter.