Managing unicorn instances / rails deployment - ruby-on-rails

Question

my head hurts today! :)
I need some help with rails deployment.
I migrated from cherokee to nginx and well, I migrated my django apps easily.
I just have to launch uwsgi to get a tcp socket and run my app. So I use supervisord to start / stop uwsgi sockets for every app.
I want something similar for rails. I just started with rails but I want to be able to deploy now so I won't have problems in a future.
I read all almost all internet and well, I have to ask here :)
My app lives in "/srv/http/hello/"
I use unicorn with a fancy config/unicorn.rb
worker_processes 2
working_directory "/srv/http/hello/"
# This loads the application in the master process before forking
# worker processes
# Read more about it here:
# http://unicorn.bogomips.org/Unicorn/Configurator.html
preload_app true
timeout 30
# This is where we specify the socket.
# We will point the upstream Nginx module to this socket later on
listen "/srv/http/hello/tmp/sockets/unicorn.sock", :backlog => 64
pid "/srv/http/hello/tmp/pids/unicorn.pid"
# Set the path of the log files inside the log folder of the testapp
stderr_path "/var/log/unicorn/hello-stderr.log"
stdout_path "/var/log/unicorn/hello-stdout.log"
before_fork do |server, worker|
# This option works in together with preload_app true setting
# What is does is prevent the master process from holding
# the database connection
defined?(ActiveRecord::Base) and
ActiveRecord::Base.connection.disconnect!
end
after_fork do |server, worker|
# Here we are establishing the connection after forking worker
# processes
defined?(ActiveRecord::Base) and
ActiveRecord::Base.establish_connection
end
I just adapted some example for internet.
If I run something like:
unicorn_rails -c config/unicorn.rb -D
It works like a charm. I tried to put that command in supervisord but hehe, I asked too much for it.
So, with some research I discovered god, so I picked the example of github and I put it on "config/god.rb" (which is the good place?)
# http://unicorn.bogomips.org/SIGNALS.html
rails_env = ENV['RAILS_ENV'] || 'development'
rails_root = ENV['RAILS_ROOT'] || "/srv/http/hello"
God.watch do |w|
w.name = "unicorn"
w.interval = 30.seconds # default
# unicorn needs to be run from the rails root
w.start = "cd #{rails_root} && /srv/http/.rvm/gems/ruby-1.9.3-p0#hello/bin/unicorn_rails -c #{rails_root}/config/unicorn.rb -E #{rails_env} -D"
# QUIT gracefully shuts down workers
w.stop = "kill -QUIT `cat #{rails_root}/tmp/pids/unicorn.pid`"
# USR2 causes the master to re-create itself and spawn a new worker pool
w.restart = "kill -USR2 `cat #{rails_root}/tmp/pids/unicorn.pid`"
w.start_grace = 10.seconds
w.restart_grace = 10.seconds
w.pid_file = "#{rails_root}/tmp/pids/unicorn.pid"
#w.uid = 'http'
#w.gid = 'webgroup'
w.behavior(:clean_pid_file)
w.start_if do |start|
start.condition(:process_running) do |c|
c.interval = 5.seconds
c.running = false
end
end
w.restart_if do |restart|
restart.condition(:memory_usage) do |c|
c.above = 300.megabytes
c.times = [3, 5] # 3 out of 5 intervals
end
restart.condition(:cpu_usage) do |c|
c.above = 50.percent
c.times = 5
end
end
# lifecycle
w.lifecycle do |on|
on.condition(:flapping) do |c|
c.to_state = [:start, :restart]
c.times = 5
c.within = 5.minute
c.transition = :unmonitored
c.retry_in = 10.minutes
c.retry_times = 5
c.retry_within = 2.hours
end
end
end
NOTE: I commented the uid and gid since I launch it from the http user or I get a permission error writing the pid. Also I put "development" because is just a "rails new hello"
Ok, so this works:
god -c config/god.rb -D
god launch unicorn good and in another terminal and I can do "god stop unicorn" and it works.
So questions...
1 - Is this the correct way?
2 - Do I need one god config for every project and launch a god process for every project?
3 - How can I manage those god's process? Something like supervisord "supervisorctl restart djangoproject"
4 - Will I die if I put "killall god" 3 times in a row? :P
5 - NEW QUESTION: Im too far if I say that I just need 1 god config with ALL unicorn instances, launch it in some form and just manage it with god? god start blah, god start bleh...
Thanks a lot, I just need to start rails development with a good system administration.

Answer 1

If you already have experience with uWSGI why not using it for rails too ?
http://projects.unbit.it/uwsgi/wiki/RubyOnRails
If you plan to host a lot of apps consider using the Emperor
http://projects.unbit.it/uwsgi/wiki/Emperor