Training with a custom service account needs a new field named service account
trainingInput:
  serviceAccount: CUSTOM_SERVICE_ACCOUNT

https://cloud.google.com/ai-platform/training/docs/custom-service-account


tests/providers/google/cloud/operators/test_mlengine.py
training_op = MLEngineStartTrainingJobOperator(**self.TRAINING_DEFAULT_ARGS)
        ti = TaskInstance(
            task=training_op,
            execution_date=DEFAULT_DATE,
        )
        job_id = self.TRAINING_DEFAULT_ARGS['job_id']
        project_id = self.TRAINING_DEFAULT_ARGS['project_id']
        gcp_metadata = {
            "job_id": job_id,
            "project_id": project_id,
        }
        ti.xcom_push(key='gcp_metadata', value=gcp_metadata)
        self.assertEqual(
            f"https://console.cloud.google.com/ai-platform/jobs/{job_id}?project={project_id}",
            training_op.get_extra_links(DEFAULT_DATE, AIPlatformConsoleLink.name),
        )
        self.assertEqual(
            '',
            training_op.get_extra_links(datetime.datetime(2019, 1, 1), AIPlatformConsoleLink.name),
        )
    def test_console_extra_link_serialized_field(self):
        with self.dag:
            training_op = MLEngineStartTrainingJobOperator(**self.TRAINING_DEFAULT_ARGS)