Bit of systemd chef code to have clients automatically remove themselves on shutdown

chef-client-cleanup.rb

# Create a systemd service that runs at shutdown to remove one's node and client from the chef server,
#  useful in AutoScale and Terraform-managed scenarios
#  not useful in cases where you may want to shutdown (but not terminate) a node

systemd_unit 'chef-cleanup.service' do
  content('Unit' => {
            'Description' => 'Delete my own Chef node and client objects at shutdown/termination',
            'DefaultDependencies' => 'no',
            'Before' => 'shutdown.target halt.target',
          },
          'Service' => {
            'Type' => 'oneshot',
            'ExecStart' => "/opt/chef/bin/knife node delete #{node.name} -y -c /etc/chef/client.rb && /opt/chef/bin/knife client delete #{node.name} -y -c /etc/chef/client.rb",
          },
          'Install' => {
            'WantedBy' => 'halt.target shutdown.target',
          })
  action [:create, :enable]
end

I try this code with Ubuntu 18.04 LTS on AWS, and my node is not unregister.
Do you have an idea ?