It is nice to see "Ruby"-discussion in the JavaRanch. We have been developing Java and related technology projects all along, and now we have a new Rails project. There was an immense confusion while deploying the rails project with the rest in the same server. Do you have anything comments on this?
Rails deployment has been a pretty big sticking point for a while now, but it is getting better. If you're deploying to a server that's already running Java applications, your best bet is probably to take a look at running your application on JRuby, in something like the Glassfish application server. The JRuby team at Sun has done a fantastic job of getting Rails running in concert with other Java systems.
I'm curious as to what kind of problems you've had with deploying on the same server as Java applications?
As far as Rails deployment goes, yes, it's been a bit of a pain compared to PHP applications and the J2EE world. Having said that, you do have tools like Capistrano which work wonders provided that you put in the effort of getting into the ropes. Once you're past the learning curve, it's devastating to go back to Java-land and realize there's nothing similar available.
Furthermore, if you've bumped into trouble trying to manage stray FastCGI/Mongrel processes, it might make sense to give Passenger (mod_rails) a try. Based on my short experience (two weeks), it's working quite well and is far more manageable than my previous FastCGI setup. And its performance seems comparable or even better than a Mongrel cluster.
I haven't used JRuby much, so haven't run into any specific problems with deployment. I have, however, tried mod_rails (more properly mod_rack now, given the just-released 2.0 version), and it's great for some environments. My typical deployment setup has Apache proxying to a mongrel cluster, with monitoring software (e.g., monit or god) helping clean up stray processes.