Mongo::Error::NoServerAvailable when running Rails app

Question

When running rails s and connecting to localhost:3000, I get the following error messages when attempting simple queries such as @users.each:

Mongo::Error::NoServerAvailable in Users#index

No server is available matching preference: #<Mongo::ServerSelector::Primary:0x62403672 tag_sets=[] server_selection_timeout=30 local_threshold=0.015>

The console shows

MONGODB | Adding localhost:3000 to the cluster
MONGODB | IOERROR

config/mongoid.yml

development:
  clients:
    default:
      database: virtu_development
      hosts:
        - localhost:3000
      options:

  options:
test:
  clients:
    default:
      database: virtu_test
      hosts:
        - localhost:3000
      options:
        read:
          mode: :primary
        max_pool_size: 1

Edit: When running with mongoid.yml set to run on localhost:27017, as is apparently appropriate, the console repeatedly reads out:

No connection could be made because the target machine actively refused it. - connect(2) for 127.0.0.1:27017

Edit 2: Running mongo.exe while in C:\Program Files\MongoDB\Server\3.2\bin yields:

MongoDB shell version: 3.2.4
connecting to: test
2016-03-31T19:14:03.597-0400 W NETWORK  [thread1] Failed to connect to 127.0.0.1:27017, reason: errno:10061 No connection could be made because the target machine actively refused it.
2016-03-31T19:14:03.597-0400 E QUERY    [thread1] Error: couldn't connect to server 127.0.0.1:27017, connection attempt failed :
connect@src/mongo/shell/mongo.js:224:14
@(connect):1:6

Running mongod.exe yields:

2016-03-31T19:13:00.636-0400 I CONTROL  [initandlisten] MongoDB starting : pid=5564 port=27017 dbpath=C:\data\db\ 64-bit host=Kalyn-PC
2016-03-31T19:13:00.640-0400 I CONTROL  [initandlisten] targetMinOS: Windows Vista/Windows Server 2008
2016-03-31T19:13:00.640-0400 I CONTROL  [initandlisten] db version v3.2.4
2016-03-31T19:13:00.640-0400 I CONTROL  [initandlisten] git version: e2ee9ffcf9f5a94fad76802e28cc978718bb7a30
2016-03-31T19:13:00.640-0400 I CONTROL  [initandlisten] allocator: tcmalloc
2016-03-31T19:13:00.640-0400 I CONTROL  [initandlisten] modules: none
2016-03-31T19:13:00.640-0400 I CONTROL  [initandlisten] build environment:
2016-03-31T19:13:00.641-0400 I CONTROL  [initandlisten]     distarch: x86_64
2016-03-31T19:13:00.641-0400 I CONTROL  [initandlisten]     target_arch: x86_64
2016-03-31T19:13:00.641-0400 I CONTROL  [initandlisten] options: {}
2016-03-31T19:13:00.642-0400 I STORAGE  [initandlisten] exception in initAndListen: 29 Data directory C:\data\db\ not found., terminating
2016-03-31T19:13:00.642-0400 I CONTROL  [initandlisten] dbexit:  rc: 100

Answer 1

I had to manually

1. change config/mongoid.yml to run at localhost:27017

2. create the empty directories C:data/db

3. then run mongod (in my specific case, navigate to C:\Program Files\MongoDB\Server\3.2\bin and run mongod.exe).

After that, starting up the rails server worked like a charm.

Answer 2

you are trying to connect to mongodb on rails port, the correct host is localhost:27017 , for local server (off course if the db runs locally)

Answer 3

I had observed a similar issue:

    MONGODB | Errno::ECONNREFUSED: Connection refused - connect(2) for 127.0.0.1:27017
  Rendered gdd_apis/index.html.erb within layouts/application (60062.0ms)
Completed 500 Internal Server Error in 60075ms



ActionView::Template::Error (No server is available matching preference: #<Mongo::ServerSelector::Primary:0x27416600 tag_sets=[] max_staleness=nil> using server_selection_timeout=30 and local_threshold=0.015):
    19:     </tr>
    20:   </thead>
    21:   <tbody>
    22:     <% if @gdd_apis.size == 0 %>
    23:       <tr>
    24:       <pis/tr>
    25:     <% else %>

app/views/gdd_apis/index.html.erb:22:in `_app_views_gdd_apis_index_html_erb___3636122846566909968_28792560'
- Gracefully stopping, waiting for requests to finish
=== puma shutdown: 2018-08-31 14:04:39 -0500 ===
- Goodbye!

I found after some searching on the internet that if the machine has IPv6 enabled, then Rails/mongoid tries to connect to mongodb via IPv6, and this was failing.

I was able to get it working by changing the hosts: entry in mongoid.yml from localhost:27017
to (machine_ipv4_address):27017