'Starts the specified virtual machine.
service_name:
The name of the service.
deployment_name:
The name of the deployment.
role_name:
The name of the role.'

def start_role(self, service_name, deployment_name, role_name):

    _validate_not_none('service_name', service_name)
    _validate_not_none('deployment_name', deployment_name)
    _validate_not_none('role_name', role_name)
    return self._perform_post(self._get_role_instance_operations_path(service_name, deployment_name, role_name), _XmlSerializer.start_role_operation_to_xml(), async=True)
