无法打开到localhost的TCP连接：9200（连接被拒绝 - 连接（2）为“localhost”端口9200）（法拉第::连接失败）

Question

我收到错误：Puma发现了这个错误：无法打开到localhost的TCP连接：9200（连接被拒绝 - 连接（2）for“localhost”端口9200）（Faraday :: ConnectionFailed）在我的rails应用程序中的ubuntu 14.04。

下面是我在终端弹性搜索的输出：

prashanth@prashanth-OptiPlex-390:~$ sudo service elasticsearch restart
 * Starting Elasticsearch Server                                                                                                               prashanth@prashanth-OptiPlex-390:~$ sudo service elasticsearch start
 * Starting Elasticsearch Server                                                                                                                * Already running.                                                                                                                     [ OK ] 
prashanth@prashanth-OptiPlex-390:~$ curl -X GET 'http://localhost:9200'
curl: (7) Failed to connect to localhost port 9200: Connection refused
prashanth@prashanth-OptiPlex-390:~$ 

这是我在/etc/elasticsearch/elasticsearch.yml文件中的弹性搜索设置

network.host: 127.0.0.1
transport.tcp.port: 9200
http.port: 9200

错误描述：

Puma caught this error: Failed to open TCP connection to localhost:9200 (Connection refused - connect(2) for "localhost" port 9200) (Faraday::ConnectionFailed)
/home/prashanth/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/net/http.rb:882:in `rescue in block in connect'
/home/prashanth/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/net/http.rb:879:in `block in connect'
/home/prashanth/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/timeout.rb:91:in `block in timeout'
/home/prashanth/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/timeout.rb:101:in `timeout'
/home/prashanth/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/net/http.rb:878:in `connect'
/home/prashanth/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/net/http.rb:863:in `do_start'
/home/prashanth/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/net/http.rb:852:in `start'
/home/prashanth/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/net/http.rb:1398:in `request'
/home/prashanth/.rvm/gems/ruby-2.3.1/gems/faraday-0.10.1/lib/faraday/adapter/net_http.rb:83:in `perform_request'
/home/prashanth/.rvm/gems/ruby-2.3.1/gems/faraday-0.10.1/lib/faraday/adapter/net_http.rb:41:in `block in call'
/home/prashanth/.rvm/gems/ruby-2.3.1/gems/faraday-0.10.1/lib/faraday/adapter/net_http.rb:88:in `with_net_http_connection'
/home/prashanth/.rvm/gems/ruby-2.3.1/gems/faraday-0.10.1/lib/faraday/adapter/net_http.rb:33:in `call'
/home/prashanth/.rvm/gems/ruby-2.3.1/gems/faraday-0.10.1/lib/faraday/rack_builder.rb:139:in `build_response'
/home/prashanth/.rvm/gems/ruby-2.3.1/gems/faraday-0.10.1/lib/faraday/connection.rb:377:in `run_request'
/home/prashanth/.rvm/gems/ruby-2.3.1/gems/elasticsearch-transport-5.0.0/lib/elasticsearch/transport/transport/http/faraday.rb:23:in `block in perform_request'
/home/prashanth/.rvm/gems/ruby-2.3.1/gems/elasticsearch-transport-5.0.0/lib/elasticsearch/transport/transport/base.rb:257:in `perform_request'
/home/prashanth/.rvm/gems/ruby-2.3.1/gems/elasticsearch-transport-5.0.0/lib/elasticsearch/transport/transport/http/faraday.rb:20:in `perform_request'
/home/prashanth/.rvm/gems/ruby-2.3.1/gems/elasticsearch-transport-5.0.0/lib/elasticsearch/transport/client.rb:128:in `perform_request'

Answer 1

在您发布的设置中，您的HTTP和TCP端口具有相同的端口号

network.host: 127.0.0.1
transport.tcp.port: 9200
http.port: 9200

我建议更改transport.tcp.port并再次尝试。

尝试使用默认值，除非您已使用端口9300：

network.host: 127.0.0.1
transport.tcp.port: 9300
http.port: 9200

如果您仍然遇到问题，可能需要打开防火墙程序上的端口。 在Ubuntu上，这可能是UFW。

如果您的服务脚本具有状态功能，则可能会告诉您Elasticsearch实例是否已正确启动。 如果不这样做，您可以使用ps aux来确定它是否正在运行。

$ sudo service elasticsearch status

要么

$ ps aux | grep elasticsearch

正如类似的问题所指出的，当Elasticsearch没有运行时，cURL会给出拒绝的连接错误（来源： Faraday :: ConnectionFailed，连接被拒绝 - 连接（2）为“localhost”端口9200错误Ruby on Rails ）。

Answer 2

你有Docker吗？ 对我来说唯一的解决方案是完全卸载Docker。 另外，我认为这个问题与Docker使用的端口有关。

如果你不像我一样使用很多，只需将它移除即可。