Redmine 数据库连接错误

/********************************************************************
 *                    Redmine 数据库连接错误
 * 说明：
 *     OpenMediaVault上的Redmine出现连接错误，目前不知道是我自己不小心
 * 把mysql的密码修改了，还是因为被攻击了，先记录一下。
 *
 *                                  2016-8-17 深圳 南山平山村 曾剑锋
 *******************************************************************/

一、参考文档：
    1. 完整过程解决 ERROR 1045 (28000): Access denied for user ‘mysql‘@‘localhost‘ (using password: NO)
        http://blog.csdn.net/nel0511/article/details/13091163

二、错误现象：
    root@workflow:/etc# ruby /usr/share/redmine/bin/rails server -p3000 webrick -e production &
    [1] 2828
    root@workflow:/etc# => Booting WEBrick
    => Rails 3.1.8 application starting in production on http://0.0.0.0:3000
    => Run `rails server -h` for more startup options
    => Notice: server is listening on all interfaces (0.0.0.0). Consider using 127.0.0.1 (--binding option)
    => Ctrl-C to shutdown server
    Exiting
    /usr/lib/ruby/vendor_ruby/mysql2/client.rb:70:in `connect‘: Access denied for user ‘root‘@‘localhost‘ (using password: YES) (Mysql2::Error)
            from /usr/lib/ruby/vendor_ruby/mysql2/client.rb:70:in `initialize‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_adapters/mysql2_adapter.rb:18:in `new‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_adapters/mysql2_adapter.rb:18:in `mysql2_connection‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_adapters/abstract/connection_pool.rb:435:in `new_connection‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_adapters/abstract/connection_pool.rb:445:in `checkout_new_connection‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_adapters/abstract/connection_pool.rb:416:in `acquire_connection‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_adapters/abstract/connection_pool.rb:351:in `block in checkout‘
            from /usr/lib/ruby/1.1.0/monitor.rb:211:in `mon_synchronize‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_adapters/abstract/connection_pool.rb:350:in `checkout‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_adapters/abstract/connection_pool.rb:265:in `block in connection‘
            from /usr/lib/ruby/1.1.0/monitor.rb:211:in `mon_synchronize‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_adapters/abstract/connection_pool.rb:264:in `connection‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_adapters/abstract/connection_pool.rb:541:in `retrieve_connection‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_handling.rb:113:in `retrieve_connection‘
            from /usr/lib/ruby/vendor_ruby/active_record/connection_handling.rb:87:in `connection‘
            from /usr/lib/ruby/vendor_ruby/active_record/model_schema.rb:209:in `table_exists?‘
            from /usr/lib/ruby/vendor_ruby/active_record/attribute_methods/primary_key.rb:99:in `get_primary_key‘
            from /usr/lib/ruby/vendor_ruby/active_record/attribute_methods/primary_key.rb:84:in `reset_primary_key‘
            from /usr/lib/ruby/vendor_ruby/active_record/attribute_methods/primary_key.rb:72:in `primary_key‘
            from /usr/lib/ruby/vendor_ruby/active_record/mass_assignment_security/attribute_assignment.rb:15:in `attributes_protected_by_default‘
            from /usr/lib/ruby/vendor_ruby/active_model/mass_assignment_security.rb:332:in `block in protected_attributes_configs‘
            from /usr/lib/ruby/vendor_ruby/active_model/mass_assignment_security.rb:217:in `yield‘
            from /usr/lib/ruby/vendor_ruby/active_model/mass_assignment_security.rb:217:in `protected_attributes‘
            from /usr/lib/ruby/vendor_ruby/active_model/mass_assignment_security.rb:123:in `block in attr_protected‘
            from /usr/lib/ruby/vendor_ruby/active_model/mass_assignment_security.rb:122:in `each‘
            from /usr/lib/ruby/vendor_ruby/active_model/mass_assignment_security.rb:122:in `attr_protected‘
            from /usr/share/redmine/app/models/custom_field.rb:32:in `<class:CustomField>‘
            from /usr/share/redmine/app/models/custom_field.rb:18:in `<top (required)>‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `require‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `block in require‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:232:in `load_dependency‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `require‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:348:in `require_or_load‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:480:in `load_missing_constant‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:180:in `const_missing‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:512:in `load_missing_constant‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:180:in `const_missing‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:512:in `load_missing_constant‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:180:in `const_missing‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:512:in `load_missing_constant‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:180:in `const_missing‘
            from /usr/share/redmine/lib/redmine/field_format.rb:80:in `field_attributes‘
            from /usr/share/redmine/lib/redmine/field_format.rb:83:in `<class:Base>‘
            from /usr/share/redmine/lib/redmine/field_format.rb:48:in `<module:FieldFormat>‘
            from /usr/share/redmine/lib/redmine/field_format.rb:19:in `<module:Redmine>‘
            from /usr/share/redmine/lib/redmine/field_format.rb:18:in `<top (required)>‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `require‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `block in require‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:232:in `load_dependency‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `require‘
            from /usr/share/redmine/lib/redmine.rb:38:in `<top (required)>‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `require‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `block in require‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:232:in `load_dependency‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `require‘
            from /usr/share/redmine/config/initializers/30-redmine.rb:6:in `<top (required)>‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:241:in `load‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:241:in `block in load‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:232:in `load_dependency‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:241:in `load‘
            from /usr/lib/ruby/vendor_ruby/rails/engine.rb:648:in `block in load_config_initializer‘
            from /usr/lib/ruby/vendor_ruby/active_support/notifications.rb:161:in `instrument‘
            from /usr/lib/ruby/vendor_ruby/rails/engine.rb:647:in `load_config_initializer‘
            from /usr/lib/ruby/vendor_ruby/rails/engine.rb:612:in `block (2 levels) in <class:Engine>‘
            from /usr/lib/ruby/vendor_ruby/rails/engine.rb:611:in `each‘
            from /usr/lib/ruby/vendor_ruby/rails/engine.rb:611:in `block in <class:Engine>‘
            from /usr/lib/ruby/vendor_ruby/rails/initializable.rb:30:in `instance_exec‘
            from /usr/lib/ruby/vendor_ruby/rails/initializable.rb:30:in `run‘
            from /usr/lib/ruby/vendor_ruby/rails/initializable.rb:55:in `block in run_initializers‘
            from /usr/lib/ruby/1.1.0/tsort.rb:226:in `block in tsort_each‘
            from /usr/lib/ruby/1.1.0/tsort.rb:348:in `block (2 levels) in each_strongly_connected_component‘
            from /usr/lib/ruby/1.1.0/tsort.rb:418:in `block (2 levels) in each_strongly_connected_component_from‘
            from /usr/lib/ruby/1.1.0/tsort.rb:427:in `each_strongly_connected_component_from‘
            from /usr/lib/ruby/1.1.0/tsort.rb:417:in `block in each_strongly_connected_component_from‘
            from /usr/lib/ruby/vendor_ruby/rails/initializable.rb:44:in `each‘
            from /usr/lib/ruby/vendor_ruby/rails/initializable.rb:44:in `tsort_each_child‘
            from /usr/lib/ruby/1.1.0/tsort.rb:411:in `call‘
            from /usr/lib/ruby/1.1.0/tsort.rb:411:in `each_strongly_connected_component_from‘
            from /usr/lib/ruby/1.1.0/tsort.rb:347:in `block in each_strongly_connected_component‘
            from /usr/lib/ruby/1.1.0/tsort.rb:345:in `each‘
            from /usr/lib/ruby/1.1.0/tsort.rb:345:in `call‘
            from /usr/lib/ruby/1.1.0/tsort.rb:345:in `each_strongly_connected_component‘
            from /usr/lib/ruby/1.1.0/tsort.rb:224:in `tsort_each‘
            from /usr/lib/ruby/1.1.0/tsort.rb:205:in `tsort_each‘
            from /usr/lib/ruby/vendor_ruby/rails/initializable.rb:54:in `run_initializers‘
            from /usr/lib/ruby/vendor_ruby/rails/application.rb:300:in `initialize!‘
            from /usr/share/redmine/config/environment.rb:14:in `<top (required)>‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `require‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `block in require‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:232:in `load_dependency‘
            from /usr/lib/ruby/vendor_ruby/active_support/dependencies.rb:247:in `require‘
            from /usr/share/redmine/config.ru:3:in `block in <main>‘
            from /usr/lib/ruby/vendor_ruby/rack/builder.rb:55:in `instance_eval‘
            from /usr/lib/ruby/vendor_ruby/rack/builder.rb:55:in `initialize‘
            from /usr/share/redmine/config.ru:in `new‘
            from /usr/share/redmine/config.ru:in `<main>‘
            from /usr/lib/ruby/vendor_ruby/rack/builder.rb:49:in `eval‘
            from /usr/lib/ruby/vendor_ruby/rack/builder.rb:49:in `new_from_string‘
            from /usr/lib/ruby/vendor_ruby/rack/builder.rb:40:in `parse_file‘
            from /usr/lib/ruby/vendor_ruby/rack/server.rb:277:in `build_app_and_options_from_config‘
            from /usr/lib/ruby/vendor_ruby/rack/server.rb:199:in `app‘
            from /usr/lib/ruby/vendor_ruby/rails/commands/server.rb:50:in `app‘
            from /usr/lib/ruby/vendor_ruby/rack/server.rb:314:in `wrapped_app‘
            from /usr/lib/ruby/vendor_ruby/rack/server.rb:250:in `start‘
            from /usr/lib/ruby/vendor_ruby/rails/commands/server.rb:69:in `start‘
            from /usr/lib/ruby/vendor_ruby/rails/commands/commands_tasks.rb:81:in `block in server‘
            from /usr/lib/ruby/vendor_ruby/rails/commands/commands_tasks.rb:76:in `tap‘
            from /usr/lib/ruby/vendor_ruby/rails/commands/commands_tasks.rb:76:in `server‘
            from /usr/lib/ruby/vendor_ruby/rails/commands/commands_tasks.rb:40:in `run_command!‘
            from /usr/lib/ruby/vendor_ruby/rails/commands.rb:17:in `<top (required)>‘
            from /usr/share/redmine/bin/rails:4:in `require‘
            from /usr/share/redmine/bin/rails:4:in `<main>‘
    
    [1]+  Exit 1                  ruby /usr/share/redmine/bin/rails server -p3000 webrick -e production

三、解决办法：
    修改数据库root密码。