opscode/chef-metal-fog — pull request #24 by thommay (2014-06-10 11:37:54+00:00)
Title: Use unix timestamps rather than strings

This means that we can use allocated_at to locate nodes older than x
using a simple solr search, rather than needing to walk every node.

From inspection I don't think we need to preserve back compat - all the usages in chef-metal-fog are short lived and will always be one or the other.