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いつもお世話になっております。

現在、[Ruby on Rails
チュートリアルの第14章](https://railstutorial.jp/chapters/following_users?version=5.1#cha-
following_users) を進めています。  
しかし、下記に示しているように、rails serverが起動しません。

```

    /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:269
    
```

のファイルを探してみたのですが、存在しないようです。  
グーグルで検索して観たのですが、これといった解決策を探しつかず、困っています。

どうぞよろしくお願いいたします。

```

    ec2-user:~/environment/sample_app (master) $ rails server
    => Booting Puma
    => Rails 5.1.4 application starting in development 
    => Run `rails server -h` for more startup options
    [4043] Puma starting in cluster mode...
    [4043] * Version 3.9.1 (ruby 2.4.1-p111), codename: Private Caller
    [4043] * Min threads: 5, max threads: 5
    [4043] * Environment: development
    [4043] * Process workers: 2
    [4043] * Preloading application
    [4043] * Listening on tcp://localhost:8080
    Exiting
    /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:269:in `initialize': Address already in use - bind(2) for "127.0.0.1" port 8080 (Errno::EADDRINUSE)
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:269:in `new'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:269:in `add_tcp_listener'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:263:in `block in add_tcp_listener'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:262:in `each'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:262:in `add_tcp_listener'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:105:in `block in parse'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:88:in `each'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:88:in `parse'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/runner.rb:144:in `load_and_bind'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/cluster.rb:391:in `run'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/launcher.rb:174:in `run'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/rack/handler/puma.rb:69:in `run'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/rack-2.0.4/lib/rack/server.rb:297:in `start'
            from /usr/local/rvm/gems/ruby-2.4.1@global/gems/railties-5.1.4/lib/rails/commands/server/server_command.rb:44:in `start'
            from /usr/local/rvm/gems/ruby-2.4.1@global/gems/railties-5.1.4/lib/rails/commands/server/server_command.rb:135:in `block in perform'
            from /usr/local/rvm/gems/ruby-2.4.1@global/gems/railties-5.1.4/lib/rails/commands/server/server_command.rb:130:in `tap'
            from /usr/local/rvm/gems/ruby-2.4.1@global/gems/railties-5.1.4/lib/rails/commands/server/server_command.rb:130:in `perform'
            from /usr/local/rvm/gems/ruby-2.4.1@global/gems/thor-0.20.0/lib/thor/command.rb:27:in `run'
            from /usr/local/rvm/gems/ruby-2.4.1@global/gems/thor-0.20.0/lib/thor/invocation.rb:126:in `invoke_command'
            from /usr/local/rvm/gems/ruby-2.4.1@global/gems/thor-0.20.0/lib/thor.rb:387:in `dispatch'
            from /usr/local/rvm/gems/ruby-2.4.1@global/gems/railties-5.1.4/lib/rails/command/base.rb:63:in `perform'
            from /usr/local/rvm/gems/ruby-2.4.1@global/gems/railties-5.1.4/lib/rails/command.rb:44:in `invoke'
            from /usr/local/rvm/gems/ruby-2.4.1@global/gems/railties-5.1.4/lib/rails/commands.rb:16:in `<top (required)>'
            from /home/ec2-user/environment/sample_app/bin/rails:9:in `require'
            from /home/ec2-user/environment/sample_app/bin/rails:9:in `<top (required)>'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/client/rails.rb:28:in `load'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/client/rails.rb:28:in `call'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/client/command.rb:7:in `call'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/client.rb:30:in `run'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/bin/spring:49:in `<top (required)>'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/binstub.rb:31:in `load'
            from /usr/local/rvm/gems/ruby-2.4.1/gems/spring-2.0.2/lib/spring/binstub.rb:31:in `<top (required)>'
            from /home/ec2-user/environment/sample_app/bin/spring:15:in `require'
            from /home/ec2-user/environment/sample_app/bin/spring:15:in `<top (required)>'
            from bin/rails:3:in `load'
            from bin/rails:3:in `<main>'
    ec2-user:~/environment/sample_app (master) $
    
```
CC BY-SA 3.0
2018-03-05T10:35:13.787
42143
2018-03-05T14:02:21.797
2018-03-05T11:14:09.567
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25182
question
ruby-on-rails ruby
rails serverが実行できない
> /usr/local/rvm/gems/ruby-2.4.1/gems/puma-3.9.1/lib/puma/binder.rb:269:in
> `initialize': Address already in use - bind(2) for "127.0.0.1" port 8080

TCP/8080 が既に他のプロセスによって使用中です。  
通信ポートを変更するか、使用中のプロセスを停止してみてください。
CC BY-SA 3.0
2018-03-05T14:02:21.797
42147
2018-03-05T14:02:21.797
5008
42143
answer