Rails异常Could not connect to a primary node for replica set #<Moped::Cluster: @seeds=[<Moped::Node resolved_address=nil>]>

Rails连接远程mongo数据库报错：

"Could not connect to a primary node for replica set #<Moped::Cluster:27191916 @seeds=[<Moped::Node resolved_address=nil>]>"

配置文件内容如下：

development:
  sessions:
    default:
      database: spider
      hosts:
        - db.***.com:10001
      options:
  options:
test:
  sessions:
    default:
      database: spider_admin_test
      hosts:
        - localhost:27017
      options:
        read: primary
        max_retries: 1
        retry_interval: 0

上stackoverflow.com找解决方案

原文地址：http://stackoverflow.com/questions/21128597/mongoid-with-rails-4-could-not-connect-to-a-primary-node-resolved-address

大致是说把域名的形式改成IP形式，于是我尝试将域名改成具体IP后，程序恢复正常，修改后如下：

development:
  sessions:
    default:
      database: spider
      hosts:
        - 0.0.0.0:10001  # 需更换成你的程序所使用的mongo服务器具体IP地址
      options:
  options:
test:
  sessions:
    default:
      database: spider_admin_test
      hosts:
        - localhost:27017
      options:
        read: primary
        max_retries: 1
        retry_interval: 0