Phusion Passenger aka mod_rails has been on a tour de force lately and rightfully so. It makes Rails deployment so much simpler and combined with REE faster and with less memory overhead. So I’m really happy to see that lots of the hosting companies in the Rails world are adopting it and making it available to their customers.

Rails Machine recently announced that Passenger is now part of their standard stack and that they’ve made it silly easy to switch from a Mongrel-based setup to Passenger. The latest Accelerator from Joyent has Passenger preconfigured as well. At the shared hosting end, Dreamhost has been supporting Passenger for a while (nice tutorial using Passenger at Dreamhost).

I’ve personally been setting up Passenger at Slicehost with Ubuntu and having great results with that. At 37signals, we’re already running Ta-da List (on EC2) and Backpack (at Rackspace) on Passenger and plan to move over the rest of the applications shortly. Our system administrators certainly appreciate not having to funk with Mongrels any more.

Lots of other hosters are in advanced testing with Passenger as well. Brightbox has been building Ubuntu packages for Passenger and is putting one together for REE. They should have complete Passenger support shortly. Most other Rails hosters I’ve talked to are at least looking into it as well.

But just because Passenger is a big step forward for Rails hosting, it doesn’t mean that other approaches are suddenly useless. There may still be situations where a traditional proxy/Mongrel setup would be relevant. For example, if you for some reason are unable to use Apache, that’s still the way to go. Rails will continue to support both FCGI, proxy/Mongrel, any Rack web server, and of course Passenger.

The change is that if you do not already have an investment in an alternative solution, or if you’re feeling pain with that solution, you should definitely consider Passenger to be the default choice for Rails.

Update: Phusion has posted a guide to how you control the Rails and Ruby environment variables under Passenger. Useful for tweaking the GC settings etc.