// machine-id: http://man7.org/linux/man-pages/man5/machine-id.5.html
  optional string machineID = 1;

  // SystemUUID reported by the node. For unique machine identification
  // MachineID is preferred. This field is specific to Red Hat hosts
  // https://access.redhat.com/documentation/en-us/red_hat_subscription_management/1/html/rhsm/uuid
  optional string systemUUID = 2;

  // Boot ID reported by the node.