Eu estou trabalhando em um livro de receitas do chef para configurar um baunilha Ubuntu 12.04.2 com nginx postgresql e unicórnio na minha caixa vagrant, mas estou entrando em problemas com o nginx, há uma exceção

undefined method `[]' for nil:NilClass

ao instalá-lo que parece se relacionar com a configuração ohai.

Eu postei tudo o que tenho aqui:

https://github.com/DonGiulio/mychef

aqui está a saída do chef-solo:

Starting Chef Client, version 11.4.0
Compiling Cookbooks...

================================================================================
Recipe Compile Error in /var/chef/cookbooks/nginx/recipes/source.rb
================================================================================


NoMethodError
-------------
undefined method `[]' for nil:NilClass


Cookbook Trace:
---------------
  /var/chef/cookbooks/nginx/recipes/ohai_plugin.rb:27:in `from_file'
  /var/chef/cookbooks/nginx/recipes/source.rb:42:in `from_file'


Relevant File Content:
----------------------
/var/chef/cookbooks/nginx/recipes/ohai_plugin.rb:

 20:  #
 21:  
 22:  ohai 'reload_nginx' do
 23:    plugin 'nginx'
 24:    action :nothing
 25:  end
 26:  
 27>> template "#{node['ohai']['plugin_path']}/nginx.rb" do
 28:    source 'plugins/nginx.rb.erb'
 29:    owner  'root'
 30:    group  'root'
 31:    mode   '0755'
 32:    notifies :reload, 'ohai[reload_nginx]', :immediately
 33:  end
 34:  
 35:  include_recipe 'ohai::default'
 36:  


[2013-11-19T14:22:23+00:00] ERROR: Running exception handlers
[2013-11-19T14:22:23+00:00] ERROR: Exception handlers complete
Chef Client failed. 0 resources updated
[2013-11-19T14:22:23+00:00] FATAL: Stacktrace dumped to /var/chef/cache/chef-stacktrace.out
[2013-11-19T14:22:23+00:00] FATAL: NoMethodError: undefined method `[]' for nil:NilClass

e aqui está o stacktrace:

$ cat /var/chef/cache/chef-stacktrace.out
Generated at 2013-11-19 14:22:23 +0000
NoMethodError: undefined method `[]' for nil:NilClass
/var/chef/cookbooks/nginx/recipes/ohai_plugin.rb:27:in `from_file'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/mixin/from_file.rb:30:in `instance_eval'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/mixin/from_file.rb:30:in `from_file'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/cookbook_version.rb:346:in `load_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:151:in `load_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:132:in `block in include_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:131:in `each'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:131:in `include_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/dsl/include_recipe.rb:26:in `include_recipe'
/var/chef/cookbooks/nginx/recipes/source.rb:42:in `from_file'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/mixin/from_file.rb:30:in `instance_eval'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/mixin/from_file.rb:30:in `from_file'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/cookbook_version.rb:346:in `load_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:151:in `load_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context/cookbook_compiler.rb:139:in `block in compile_recipes'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context/cookbook_compiler.rb:137:in `each'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context/cookbook_compiler.rb:137:in `compile_recipes'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context/cookbook_compiler.rb:74:in `compile'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:86:in `load'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/client.rb:224:in `setup_run_context'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/client.rb:467:in `do_run'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/client.rb:200:in `run'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/application.rb:190:in `run_chef_client'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/application/solo.rb:239:in `block in run_application'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/application/solo.rb:231:in `loop'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/application/solo.rb:231:in `run_application'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/application.rb:73:in `run'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/bin/chef-solo:25:in `<top (required)>'
/usr/bin/chef-solo:23:in `load'
/usr/bin/chef-solo:23:in `<main>'

ATUALIZAÇÃO 1 Estou provisionando a caixa comruby-2.0.0-p247, há uma dependência de uma versão anterior do ruby, talvez?

UPDATE 2 eu tentei comruby-1.9.3-p448, em uma caixa recém-provisionada, mesmo problema, sem alteração.

Podes ajudar-me, por favor?

obrigado,