Comment 2 for bug 1626126

I was curious as to why nova seemed to do the right thing. It might be a happy accident. The puppet module defaults workers to undef and the puppet code contains something like this:

  if $workers {
    nova_config {
      'conductor/workers': value => $workers;
    }
  }

Leaving it up to the conductor (or whatever) code to determine the default. I'm not sure which way is way is better: having processorcount as default in puppet or leaving it unset and letting the code decide.