无法将Array转换为String

Question

我的recipes/default.rb中有以下命令：

 data = data_bag_item('config','info')

 bash "setup_hadoop" do
   user "#{node[:cluster][:user]}"
   group "#{node[:cluster][:user]}"
   cwd "#{node[:cluster][:home]}"
   code <<-EOF
     wget http://apache.mirror.gtcomm.net/hadoop/common/hadoop-1.2.1/hadoop-1.2.1.tar.gz
     tar -xzvf hadoop-1.2.1.tar.gz
     mv hadoop-1.2.1 hadoop
   EOF

    template "#{node[:cluster][:hadoop]}/hadoop-env.sh" do
       source "hadoop-env.sh.erb"
       mode 0755
       owner "#{node[:cluster][:user]}"
       group "#{node[:cluster][:user]}"
       variables( :cluster_size => data['cluster_size'] )
   end

我在info.json中有json文件/data_bag/config/：

{
   "id": "info",
   "cluster_size": 2
}

但是，当我尝试使用数据包时，出现以下错误：

[2014-05-05T14:35:45+00:00] INFO: Running start handlers
[2014-05-05T14:35:45+00:00] INFO: Start handlers complete.
[2014-05-05T14:35:45+00:00] ERROR: Failed to load data bag item: "config" "info"

================================================================================
Recipe Compile Error in /tmp/vagrant-chef-6/chef-solo-1/cookbooks/cluster/recipes/default.rb
================================================================================


TypeError
---------
can't convert Array into String


Cookbook Trace:
---------------
  /tmp/vagrant-chef-6/chef-solo-1/cookbooks/cluster/recipes/default.rb:10:in `from_file'


Relevant File Content:
----------------------
/tmp/vagrant-chef-6/chef-solo-1/cookbooks/cluster/recipes/default.rb:
    TypeError
    ---------
can't convert Array into String
 10>> data = data_bag_item('config','info')
 11:  
 12:  bash "setup_hadoop" do
 13:     user "#{node[:cluster][:user]}"
 14:     group "#{node[:cluster][:user]}"
 15:     cwd "#{node[:cluster][:home]}"
 16:     code <<-EOF
 17:     wget http://apache.mirror.gtcomm.net/hadoop/common/hadoop-1.2.1/hadoop-1.2.1.tar.gz
 18:     tar -xzvf hadoop-1.2.1.tar.gz
 19:     mv hadoop-1.2.1 hadoop
 20:     variables( :cluster_size => data['cluster_size'] )

为确保正确加载数据包，我跑了：

knife data bag show config info
cluster_size: 2
id:           info

这似乎是正确的。有人可以帮帮我吗？我按照this教程创建了数据包。