我正在尝试使用橡胶第一次将其部署到我的AWS EC2。为了测试即时消息，请立即使用t1.micro。
我在tcap rubber之后编辑了rubber.yml后，得到了一个奇怪的错误信息：create_staging
这是消息：
/Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/rubber-2.5.5/lib/rubber/environment.rb:1:in `expand_string': undefined method `known_roles' for nil:NilClass (NoMethodError)
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/rubber-2.5.5/lib/rubber/environment.rb:168:in `eval'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/rubber-2.5.5/lib/rubber/environment.rb:168:in `expand_string'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/rubber-2.5.5/lib/rubber/environment.rb:180:in `expand'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/rubber-2.5.5/lib/rubber/environment.rb:146:in `[]'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/rubber-2.5.5/lib/rubber/environment.rb:230:in `method_missing'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/rubber-2.5.5/lib/rubber/recipes/rubber/utils.rb:22:in `block (2 levels) in load'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/configuration/execution.rb:138:in `instance_eval'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/configuration/execution.rb:138:in `invoke_task_directly'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/configuration/callbacks.rb:25:in `invoke_task_directly_with_callbacks'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/configuration/execution.rb:89:in `execute_task'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/configuration/execution.rb:101:in `find_and_execute_task'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/cli/execute.rb:46:in `block in execute_requested_actions'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/cli/execute.rb:45:in `each'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/cli/execute.rb:45:in `execute_requested_actions'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/cli/help.rb:19:in `execute_requested_actions_with_help'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/cli/execute.rb:34:in `execute!'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/lib/capistrano/cli/execute.rb:14:in `execute'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/gems/capistrano-2.15.5/bin/cap:4:in `<top (required)>'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/bin/cap:23:in `load'
from /Users/mgreschke/Dropbox/medisupply/vendor/bundle/bin/cap:23:in `<main>'
知道在哪里寻找错误吗？对我来说，这似乎是一个简单的问题，但我真的不知道在哪里看。
最好，
中号
最佳答案
只需删除rubber_env。
staging_roles: "#{known_roles.reject {|r| r =~ /slave/ || r =~ /^db$/ }.join(',')}"
# instead of
staging_roles: "#{rubber_env.known_roles.reject {|r| r =~ /slave/ || r =~ /^db$/ }.join(',')}"
有一个简单的修复方法https://github.com/rubber/rubber/pull/406/files。