The vTR service is designed to perform a connectivity test in place of the subscriber. It will save you time and costs of sending a truck to the subscriber premises to perform the same kind of test.
To onboard this service in your system, you can execute the onboard-vtr.yaml playbook, using this command:
ansible-playbook -i /etc/maas/ansible/pod-inventory --extra-vars=@/opt/cord/build/genconfig/config.yml onboard-vtr-playbook.yaml