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

I am getting the error: Puma caught this error: Failed to open TCP connection to localhost:9200 (Connection refused - connect(2) for "localhost" port 9200) (Faraday::ConnectionFailed) in my rails application in ubuntu 14.04.

below is the output of my elastic search in terminal:

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:~$ 

here are the my elastic search settings in /etc/elasticsearch/elasticsearch.yml file

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

error description:

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

In the settings you posted, your HTTP and TCP ports have the same port number assigned

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

I would suggest changing the transport.tcp.port and trying again.

Try using the defaults unless you already have port 9300 in use:

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

If you are still facing issues, you may need to open up the ports on your firewall program. On Ubuntu, this is likely UFW.

If your service script has a status function, this may tell you if your Elasticsearch instance has started up properly or not. Failing this, you can use ps aux to determine if it is running.

$ sudo service elasticsearch status

Or

$ ps aux | grep elasticsearch

As pointed out in similar questions, cURL can give a refused connection error when Elasticsearch isn't running (source: Faraday::ConnectionFailed, Connection refused - connect(2) for “localhost” port 9200 Error Ruby on Rails ).

Answer 2

Do you have Docker? The only solution for me was unninstall Docker completely. Otherwhise, i think the problem is something about the port that docker use.

If you don't use alot like me, just remove it and you're good to go.