keep_last_run_list.rb

gistfile1.rb

# This should be in a recipe, as early in the run list as possible
begin
  node.override[:previous_run_list] = JSON.parse(Chef::FileCache.load("previous_run_list"))
rescue Chef::Exceptions::FileNotFound
  Chef::Log.debug("No stored run list!")
end

Chef::FileCache.store("previous_run_list", node.run_list.to_json)

# When you want to check if the last run list had the previous role...
if node.previous_run_list.include?("role[master]")
...
end