rails s で「WARN TCPServer Error: Address already in use - bind(2)」エラー

Mac Rails Ruby

Rails サーバを起動しようとしたらエラーがでました。
こんな感じです。

$ rails s
=> Booting WEBrick
=> Rails 3.1.3 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2012-01-12 13:49:02] INFO  WEBrick 1.3.1
[2012-01-12 13:49:02] INFO  ruby 1.9.3 (2011-10-30) [x86_64-darwin11.2.0]
[2012-01-12 13:49:02] WARN  TCPServer Error: Address already in use - bind(2)
Exiting
/Users/shiori/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/utils.rb:85:in `initialize': Address already in use - bind(2) (Errno::EADDRINUSE)
	from /Users/shiori/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/utils.rb:85:in `new'
	from /Users/shiori/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/utils.rb:85:in `block in create_listeners'
	from /Users/shiori/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/utils.rb:82:in `each'
	from /Users/shiori/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/utils.rb:82:in `create_listeners'
	from /Users/shiori/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/server.rb:82:in `listen'
	from /Users/shiori/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/server.rb:70:in `initialize'
	from /Users/shiori/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:45:in `initialize'
	from /Users/shiori/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.5/lib/rack/handler/webrick.rb:10:in `new'
	from /Users/shiori/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.5/lib/rack/handler/webrick.rb:10:in `run'
	from /Users/shiori/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.5/lib/rack/server.rb:265:in `start'
	from /Users/shiori/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.1.3/lib/rails/commands/server.rb:70:in `start'
	from /Users/shiori/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.1.3/lib/rails/commands.rb:54:in `block in <top (required)>'
	from /Users/shiori/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.1.3/lib/rails/commands.rb:49:in `tap'
	from /Users/shiori/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.1.3/lib/rails/commands.rb:49:in `<top (required)>'
	from script/rails:6:in `require'
	from script/rails:6:in `<main>'

これの原因なのですが、どこかでWEBrickを使用していたりすることが原因みたいです。
自分の場合は、Rubyサーバが動いていたことが原因でした。
・・・起動した覚えがないんだけどな。

プロセス確認は次のようにしてみましょう。

$ lsof -i:3000                                                                                                
COMMAND  PID   USER   FD   TYPE     DEVICE SIZE/OFF NODE NAME
ruby    2181 shiori    9u  IPv4 0x11ba7338      0t0  TCP *:hbci (LISTEN)

WEBrickだと、Ruby関係が多いので次でも確認ができます。

$ ps -af | grep ruby                                                                                          
  501  2181  2111   0  2:02PM ttys001    0:03.27 /Users/shiori/.rvm/rubies/ruby-1.9.3-p0/bin/ruby script/rails s

プロセスをkillしてあげれば問題なく動きます。

kill -9 2181

参考
http://d.hatena.ne.jp/is0me/20100108/1262946770