Getting Rails in the pool

Let’s get a fully-automated, scalable rails web application in the pool.

First, let’s generate the rails app

rails poolparty_app

Keeping my directories together:

cd poolparty_app

Now, build your app… I can wait…

Ready? Now edit the pool.spec to add rails… Sample rails setup:

pool :clouds do

cloud :app do
instances 2..3

has_directory “/var/www”
has_git_repos “my_app” do
at “/var/www”
source “git://github.com/auser/my_app.git”
owner “www-data”
end

chef do
include_recipes “~/.poolparty/chef/cookbooks/*”

recipe “/Users/alerner/.poolparty/chef_recipe.rb”
templates “/Users/alerner/.poolparty/templates/”
end
end
end

Note that we are using chef recipes. A chef tutorial is out of scope for this tutorial, but the chef recipe that we are using here looks like:

  include_recipe "apache2"
  include_recipe "passenger"

  node[:rails][:version] = "2.3.2"
  include_recipe "rails"

  web_app "paparazzi" do
    docroot "/var/www/paparazzi/public"
    template "paparazzi.conf.erb"
    server_name "www.paparazzi.com"
    server_aliases [node[:hostname], node[:fqdn], "paparazzi.com"]
    rails_env "production"  
  end

Note that this references a template called “paparazzi.conf.erb.” That looks like this

  <VirtualHost *:8080>
    ServerName <%= @params[:server_name] %>
    ServerAlias <% @params[:server_aliases].each do |a| %><%= "#{a}" %> <% end %>
    DocumentRoot <%= @params[:docroot] %>

    RailsBaseURI /
    RailsEnv <%= @params[:rails_env] %>
    RailsAllowModRewrite on
    PassengerMaxPoolSize <%= @node[:rails][:max_pool_size] %>

    <Directory <%= @params[:docroot] %>>
      Options FollowSymLinks
      AllowOverride None
      Order allow,deny
      Allow from all
    </Directory>

    LogLevel info
    ErrorLog <%= @node[:apache][:log_dir] %>/<%= @params[:name] %>-error.log
    CustomLog <%= @node[:apache][:log_dir] %>/<%= @params[:name] %>-access.log combined
  </VirtualHost>

Full gist here: http://gist.github.com/25097

Note, this is a chef recipe, so check out the chef tutorials here: http://wiki.opscode.com/

For the time being, we won’t worry about the database-side of the app as we’ll get to that in another tutorial.

Now, let’s go into the clouds directory RAILS_ROOT:

cloud start

Now your cloud is starting up. Depending on your setup, this process can take up to 10 minutes