= Known Issues * Rails 2.3.2 bundles its own version of Rack. This may cause subtle bugs when simultaneously loaded with the system-wide Rack Rubygem which Unicorn depends on. Upgrading to Rails 2.3.4 (or later) is strongly recommended for all Rails 2.3.x users for this (and security reasons). Rails 2.2.x series (or before) did not bundle Rack and are should be unnaffected. If there is any reason which forces your application to use Rails 2.3.2 and you have no other choice, then you may edit your Unicorn gemspec and remove the Rack dependency. ref: http://mid.gmane.org/20091014221552.GA30624@dcvr.yhbt.net Note: the workaround described in the article above only made the issue more subtle and we didn't notice them immediately. * Installing "unicorn" as a system-wide Rubygem and using the {isolate}[http://github.com/jbarnette/isolate] gem may cause issues if you're using any of the bundled application-level libraries in unicorn/app/* (for compatibility with CGI-based applications, Rails <= 2.2.2, or ExecCgi). For now workarounds include: * installing the same version of unicorn as a system-wide Rubygem _and_ isolating unicorn as well. * explicitly setting RUBYLIB or $LOAD_PATH to include any gem path where the unicorn gem is installed (e.g. /usr/lib/ruby/gems/1.8/gems/unicorn-VERSION/lib) * WONTFIX: code reloading and restarts with Sinatra 0.3.x (and likely older versions) apps is broken. The workaround is to force production mode to disable code reloading as well as disabling "run" in your Sinatra application: set :env, :production set :run, false Since this is no longer an issue with Sinatra 0.9.x apps, this will not be fixed on our end. Since Unicorn is itself the application launcher, the at_exit handler used in old Sinatra always caused Mongrel to be launched whenever a Unicorn worker was about to exit. Also remember we're capable of replacing the running binary without dropping any connections regardless of framework :)