You're installing user Rubies with the rbenv
cookbook. In your case, the rbenv::system
recipe is doing nothing, since you didn't specify any system Ruby to install.
Instead, include the rbenv::user
recipe:
...
chef.add_recipe "ruby_build"
chef.add_recipe "rbenv::vagrant"
chef.add_recipe "rbenv::user" ### This is the recipe you want
chef.json = {
'rbenv' => {
'user_installs' => [
{
'user' => 'vagrant',
'rubies' => ['2.0.0-p247'],
...