We're deploying with cap and using a script that send USR2 to the unicorn process to reload and it usually works but every once in a while it will fail. When that happens looking in the unicorn log reveals that it's looking for a Gemfile in an old release directory that no longer exists.
Exception :
/usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/definition.rb:14:in `build': /var/www/railsapps/inventory/releases/20111128233407/Gemfile not found (Bundler::GemfileNotFound)
To clarify that's not the current release but an older one that's since been removed.
When it works it does seem to work correctly - ie it does pickup the new code - so I don't think it's somehow stuck referring to the old release.
Any ideas?
You should set the BUNDLE_GEMFILE environment variable before you start the server, point it at current/Gemfile.