I've created an nginx/unicorn/capistrato setup on Ubuntu (Amazon EC2) by following mostly this guide. I guess everything is set up like it should but when I start Unicorn I get (a LOT of) this error in the log: E, [2012-09-08T08:57:20.658092 #12356] ERROR -- : Operation not permitted (Errno::EPERM) /home/deployer/apps/bridgekalenderen.no/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/worker.rb:82:in `initgroups' I see it's related to the user's permissions but I just can't figure out what I've left out. The server starts up nicely if I start it with sudo (or, rvmsudo, really). The user has sudo capabilities, I have chmod'ed the app several times so the file permissions there should be ok. The unicorn socket in /tmp is owned by the deployer user, so that shouldn't be the problem either. Does anybody have a clue where to look?