问题
Our application runs two Rails servers at different ports that talk to each other. Using Rails 3.2.8, I could open a terminal, cd to the project, run rails s -p3000, open another terminal, run rails s -p3001 and everything worked fine. The gemfile contains thin, so thin would be launched automatically, but using the rails s would allow using the --debugger when needed.
Since updating the Rails 3.2.11 this no longer works. I get an error: "A server is already running. Check /home/george/Projects/dashboard/tmp/pids/server.pid". I can launch thin directly on both ports, but then have no debugging support. Launching thin on one and rails on the other seemed to not work, but it was not clear that all the server tasks were getting killed when the error stopped the server.
回答1:
Both commands are checking the default PID file location (tmp/pids/server.pid), so you're seeing this error. Try running multiple servers like so:
Server 1: bundle exec rails s
Server 2: bundle exec rails s -p 3001 -P tmp/pids/server2.pid
回答2:
Posted elsewhere on Stackoverflow was the mention that if you have problems with rails 3.2.11, try locking rack at 1.4.1. This seems to work so far. I added:
gem 'rack' , '1.4.1'
to the gemfile, and then executed
bundle update rack
回答3:
try using foreman https://github.com/ddollar/foreman
Railscast: http://railscasts.com/episodes/281-foreman?view=comments
来源：https://stackoverflow.com/questions/14329370/rails-update-to-3-2-11-breaks-running-multiple-servers