Registration schema:

UUID
=========
    - If there is UUID already generated for the system will be
      available in /etc/vdsm/vdsm.id

    - In case, there is no UUID, generate it and store in /etc/vdsm/vdsm.id

Legacy reg:
============
    - REQUIRED_FOR: Engine 3.3

    - Process UUID

    - Download CA via
      https://ENGINE_FQDN

    - Download ssh pub key
      https://ENGINE_FQDN/engine.ssh.key.txt

    - Register via URL:
      (Original .NET version and earlier Linux versions)
      https://ENGINE_FQDN/RHEVManagerWeb/VdsAutoRegistration.aspx
      ?vds_ip=NODE_FQDN_OR_IP&vds_name=NODE_NAME
      &vds_unique_id=NODE_UUID&port=54321

      or

      https://ENGINE_FQDN/OvirtEngineWeb/register?vds_ip=NODE_FQDN_OR_IP
      &vds_name=NODE_NAME
      &vds_unique_id=NODE_UUID&port=54321

Service reg:
============
    - REQUIRED_FOR: Engine >= 3.4

    - Process UUID

    - Download CA via get-pki-trust URL
      https://ENGINE_FQDN/ovirt-engine/services/host-register?version=1
      &command=get-pki-trust

    - Download ssh pub key via get-ssh-trust URL
      https://ENGINE_FQDN/ovirt-engine/services/host-register?version=1
      &command=get-ssh-trust

    - Register via URL:
      https://ENGINE_FQDN/ovirt-engine/services/host-register?version=1
      &command=register&name=NODE_NAME&address=NO_FQDN_OR_IP
      &uniqueId=NODE_UUID&sshUser=SSH_USERNAME&sshPort=SSHD_PORT
