Are there any easy instructions for migrating from Phusion Passenger to Unicorn?

I am running into deployment issues with Phusion Passenger on a fairly large app: stalled processes on high loads, idle processes, slow firing up of an instance, etc. So I was looking into Unicorn, which I like very much from an architecture/pe开发者_JS百科rformance perspective.

Are there any easy to follow migration guides to go from Nginx Phusion Passenger to Unicorn?

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This question is old, and my answer doesn't answer the question directly, but I just came across a fairly details deployment guide for a stack using Unicorn, nginx, etc:

http://techbot.me/2010/08/deployment-recipes-deploying-monitoring-and-securing-your-rails-application-to-a-clean-ubuntu-10-04-install-using-nginx-and-unicorn/

Thought I would throw it out there for people who come across this question in the future.

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Because newer versions of Rails use Rack under the hood, it should be fairly easy to switch between web servers. When simply starting Unicorn with your application in a development environment, what specific issues are you encountering?

You should be able to keep using Nginx as a reverse proxy. From what I've gathered, Unicorn is supposed to do the load balancing across workers itself, because it only has a single listening socket/port it shares across them. Thus Nginx should normally be configured as a very simple reverse proxy and asset server, without load balancing. (Except, of course, when spreading workers across machines.)

Is there a specific dependence on Passenger within your application that you're hoping to solve? Or are you asking for generic deployment instructions for Unicorn?

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These issues have since been solved in Phusion Passenger. Phusion Passenger 4 fully supports asynchronous process spawning, offers protection against stuck processes, supports rolling restarts, etc. From an architectural perspective, Phusion Passenger 4 has adopted a hybrid evented/multi-threaded/multi-process design. It's like a merge between Unicorn, Rainbows and Puma, but it offers easy configuration options to seamlessly switch mode.