puma - Rails: Address already in use - bind(2) (Errno::EADDRINUSE)

Question

I am trying to deploy Rails app with the Puma web server. When trying to start Puma server with a config file bundle exec puma -C config/puma.rb I get an error that the address is already in use.

Does someone know how to fix this?

bundle exec puma -C config/puma.rb
[23699] Puma starting in cluster mode...
[23699] * Version 2.11.3 (ruby 2.0.0-p353), codename: Intrepid Squirrel
[23699] * Min threads: 5, max threads: 5
[23699] * Environment: development
[23699] * Process workers: 2
[23699] * Preloading application
Jdbc-MySQL is only for use with JRuby
[23699] * Listening on tcp://0.0.0.0:3000
/.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:210:in `initialize': Address already in use - bind(2) (Errno::EADDRINUSE)
    from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:210:in `new'
    from /Users/lexi87/.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:210:in `add_tcp_listener'
    from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:96:in `block in parse'
    from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:82:in `each'
    from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:82:in `parse'
    from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/runner.rb:119:in `load_and_bind'
    from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/cluster.rb:302:in `run'
    from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/cli.rb:216:in `run'
    from /rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/bin/puma:10:in `<top (required)>'
    from /.rvm/gems/ruby-2.0.0-p353/bin/puma:23:in `load'
    from /.rvm/gems/ruby-2.0.0-p353/bin/puma:23:in `<main>'
    from /.rvm/gems/ruby-2.0.0-p353/bin/ruby_executable_hooks:15:in `eval'
    from /.rvm/gems/ruby-2.0.0-p353/bin/ruby_executable_hooks:15:in `<main>'

Answer 1

You need to use kill -9 59780 with 59780 replaced with found PID number (use lsof -wni tcp:3000 to see which process used 3000 port and get the process PID).

Or you can just modify your puma config change the tcp port tcp://127.0.0.1:3000 from 3000 to 9292 or other port that not been used.

Or you can start your rails app by using:

bundle exec puma -C config/puma.rb -b tcp://127.0.0.1:3001