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**Description**

Airflow 1.10 support providing a run_id to TriggerDagRunOperator using [DagRunOrder](https://github.com/apache/airflow/blob/v1-10-stable/airflow/operators/dagrun_operator.py#L30-L33) object that will be returned after calling [TriggerDagRunOperator#python_callable](https://github.com/apache/airflow/blob/v1-10-stable/airflow/operators/dagrun_operator.py#L88-L95). With https://github.com/apache/airflow/pull/6317 (Airflow 2.0), this behavior changed and one could not provide run_id anymore to the triggered dag, which is very odd to say the least.

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**Use case / motivation**

I want to be able to provide run_id for the TriggerDagRunOperator. In my case, I use the TriggerDagRunOperator to trigger 30K dag_run daily and will be so annoying to see them having unidentifiable run_id.

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After discussing with @ashb
**Suggested fixes can be**
 * provide a templated run_id as a parameter to TriggerDagRunOperator.
 * restore the old behavior of Airflow 1.10, where DagRunOrder holds the run_id and dag_run_conf of the triggered dag
 * create a new sub-class of TriggerDagRunOperator to fully customize it

**Are you willing to submit a PR?**

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**Related Issues**

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tests/operators/test_trigger_dagrun.py
def setUp(self):
        
        
        with tempfile.NamedTemporaryFile(mode="w", delete=False) as f:
            self._tmpfile = f.name
            f.write(DAG_SCRIPT)
            f.flush()
        with create_session() as session:
            session.add(DagModel(dag_id=TRIGGERED_DAG_ID, fileloc=self._tmpfile))
            session.commit()
        self.dag = DAG(TEST_DAG_ID, default_args={"owner": "airflow", "start_date": DEFAULT_DATE})
        dagbag = DagBag(f.name, read_dags_from_db=False, include_examples=False)
        dagbag.bag_dag(self.dag, root_dag=self.dag)
        dagbag.sync_to_db()
    def tearDown(self):
        """Cleanup state after testing in DB."""
        with create_session() as session:
            session.query(Log).filter(Log.dag_id == TEST_DAG_ID).delete(synchronize_session=False)
            for dbmodel in [DagModel, DagRun, TaskInstance, SerializedDagModel]:
                session.query(dbmodel).filter(dbmodel.dag_id.in_([TRIGGERED_DAG_ID, TEST_DAG_ID])).delete(
                    synchronize_session=False
                )
        pathlib.Path(self._tmpfile).unlink()
    def test_trigger_dagrun(self):