Distribute Custom Ohai plugin and use it immediately with lazy block.

recipe_ec2_tags.rb

ohai 'reload_ec2_tags' do
  plugin 'ec2/tags'
  action :nothing
end

cookbook_file "#{node[:ohai][:plugin_path]}/ec2_tags.rb" do
  notifies :reload, 'ohai[reload_ec2_tags]', :immediately
end

log 'Ohai plugin ec2/tags' do
  message lazy { "#{node[:ec2][:tags]}" }
end