$ vi database.yml
(Full database.yml contents)
development:
encoding: unicode
adapter: postgresql
username: someuser
pool: 10
port: 5432
host: 10.55.333.222 <This is not a real IP address>
database: myrailsapp
password: mypassword
min_messages: WARNING
$ RAILS_ENV=development rake db:migrate <br />
(in /var/www/dress_rails_app) <br />
rake aborted! <br />
could not connect to server: Connection refused
Is the server running on host "localhost" (127.0.0.1) and accepting
TCP/IP connections on port 5432? <br />
Tasks: TOP => db:migrate => environment <br />
(See full trace by running task with --trace) <br />
我没有尝试连接到（127.0.0.1/localhost）。我正在尝试连接到远程主机，但我的database.yml被忽略。我正在尝试连接到postgresql远程主机，但我的database.yml被忽略，我的ruby应用程序继续尝试连接到localhost。
这是完整的堆栈跟踪：
(in /var/www/dress_rails_app)
** Invoke db:migrate (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
could not connect to server: Connection refused
Is the server running on host "localhost" (127.0.0.1) and accepting
TCP/IP connections on port 5432?
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/postgresql_adapter.rb:1206:in `initialize'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/postgresql_adapter.rb:1206:in `new'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/postgresql_adapter.rb:1206:in `connect'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/postgresql_adapter.rb:329:in `initialize'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `new'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `postgresql_connection'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:309:in `new_connection'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:319:in `checkout_new_connection'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:241:in `block (2 levels) in checkout'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:236:in `loop'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:236:in `block in checkout'
/usr/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:233:in `checkout'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:96:in `block in connection'
/usr/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:95:in `connection'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:404:in `retrieve_connection'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_specification.rb:168:in `retrieve_connection'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_specification.rb:142:in `connection'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/model_schema.rb:308:in `clear_cache!'
/var/lib/gems/1.9.1/gems/activerecord-3.2.6/lib/active_record/railtie.rb:97:in `block (2 levels) in <class:Railtie>'
/var/lib/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:418:in `_run__486199626554910505__prepare__4301182059246596778__callbacks'
/var/lib/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:405:in `__run_callback'
/var/lib/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:385:in `_run_prepare_callbacks'
/var/lib/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:81:in `run_callbacks'
/var/lib/gems/1.9.1/gems/actionpack-3.2.6/lib/action_dispatch/middleware/reloader.rb:74:in `prepare!'
/var/lib/gems/1.9.1/gems/actionpack-3.2.6/lib/action_dispatch/middleware/reloader.rb:48:in `prepare!'
/var/lib/gems/1.9.1/gems/railties-3.2.6/lib/rails/application/finisher.rb:47:in `block in <module:Finisher>'
/var/lib/gems/1.9.1/gems/railties-3.2.6/lib/rails/initializable.rb:30:in `instance_exec'
/var/lib/gems/1.9.1/gems/railties-3.2.6/lib/rails/initializable.rb:30:in `run'
/var/lib/gems/1.9.1/gems/railties-3.2.6/lib/rails/initializable.rb:55:in `block in run_initializers'
/var/lib/gems/1.9.1/gems/railties-3.2.6/lib/rails/initializable.rb:54:in `each'
/var/lib/gems/1.9.1/gems/railties-3.2.6/lib/rails/initializable.rb:54:in `run_initializers'
/var/lib/gems/1.9.1/gems/railties-3.2.6/lib/rails/application.rb:136:in `initialize!'
/var/lib/gems/1.9.1/gems/railties-3.2.6/lib/rails/railtie/configurable.rb:30:in `method_missing'
/var/www/dress_rails_app/config/environment.rb:5:in `<top (required)>'
/var/lib/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/dependencies.rb:251:in `require'
/var/lib/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/dependencies.rb:251:in `block in require'
/var/lib/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/dependencies.rb:236:in `load_dependency'
/var/lib/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/dependencies.rb:251:in `require'
/var/lib/gems/1.9.1/gems/railties-3.2.6/lib/rails/application.rb:103:in `require_environment!'
/var/lib/gems/1.9.1/gems/railties-3.2.6/lib/rails/application.rb:292:in `block (2 levels) in initialize_tasks'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/usr/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:176:in `block in invoke_prerequisites'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:174:in `each'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:174:in `invoke_prerequisites'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:157:in `block in invoke_with_call_chain'
/usr/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/var/lib/gems/1.9.1/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/usr/local/bin/rake:19:in `load'
/usr/local/bin/rake:19:in `<main>'
Tasks: TOP => db:migrate => environment
这是验证database.yml文件中的YAML的输出：
$ irb
irb(main):001:0> require 'yaml'
=> true
irb(main):002:0> db_yaml = YAML.load_file('/var/www/dress_rails_app/config/database.yml')
=> {"development"=>{"encoding"=>"unicode", "adapter"=>"postgresql", "pool"=>10, "port"=>5432, "username"=>"someuser", "database"=>"dress_rails_app", "password"=>"somepassword", "host"=>"10.4.66.18"}}
irb(main):003:0> puts db_yaml.inspect
{"development"=>{"encoding"=>"unicode", "adapter"=>"postgresql", "pool"=>10, "port"=>5432, "username"=>"someuser", "database"=>"dress_rails_app", "password"=>"somepassword", "host"=>"10.4.66.18"}}
=> nil
答案 0 :(得分：2)
database.yml看起来是正确的，但我会尝试验证它。
验证yml是否有效
require 'yaml'
db_yaml = YAML.load_file('/path/to/database.yml')
puts db_yaml.inspect
确保您可以读取/解析它，并且没有错误选项卡等。我在我的登台服务器上使用几乎相同的配置，它按预期工作
staging:
adapter: postgresql
database: staging_db
username: doon
password: my_password
host: 172.20.0.99
答案 1 :(得分：0)
我遇到了完全相同的问题。
在activerecord中调试postgresql_adapter后 - 我找到了解决方案
在database.yml中，只需替换host: <ip address>
与hostname: <ip address>