amoghrajesh opened a new pull request, #69914:
URL: https://github.com/apache/airflow/pull/69914
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### Why?
KPO's existing `reattach_on_restart` relies on a label search on every
retry, which can raise `FoundMoreThanOnePodFailure` when more than one matching
pod exists, and gives no way to reconnect to a specific pod unambiguously. On
Airflow 3.3+, persisting the running pod's identity to task state store lets a
retry reconnect directly to that exact pod instead, removing the ambiguity
window entirely. `reattach_on_restart` is deprecated in favor of a new durable
flag that supersedes it; existing configurations map onto durable with zero
behavior change, and pre-3.3 environments keep today's label-search behavior
unchanged.
### Summary
- Adds a `durable` parameter to `KubernetesPodOperator` (default `True`),
superseding the
deprecated `reattach_on_restart` parameter.
- On Airflow 3.3+, `durable=True` persists the running pod's identity (name,
namespace, uid)
to task state store before the operator waits on it. On retry, the
operator reconnects
directly to that pod via a direct `read_namespaced_pod` lookup instead of
a label search --
removing the `FoundMoreThanOnePodFailure` ambiguity window a label search
can hit when more
than one matching pod exists.
- The existing label-search mechanism (`find_pod()`) is retained as a
one-time bootstrap
fallback: a pod created by a pre-upgrade provider version (no persisted
identity yet) is
still found via labels on the first retry after upgrading, and that retry
starts persisting
state for every subsequent one. No in-flight task or existing pod breaks
across an upgrade.
- `reattach_on_restart` still works, mapping its value onto `durable` with
zero behavior
change; passing it emits `AirflowProviderDeprecationWarning` on Airflow
3.3+ only (below
3.3, `durable`/task state store don't functionally exist yet, so warning
would be
premature).
- `durable=False` opts out of task state store entirely, preserving today's
`reattach_on_restart=False`
behavior exactly, including its pre-existing incidental-cleanup quirk (an
orphaned pod from
a killed prior attempt can still get found and deleted via unconditional
`find_pod()`
refetch calls elsewhere in `execute_sync`/`execute_async` -- unrelated to
and unchanged by
this work).
- Docs: added a "Durable execution" section to KPO's operator docs,
cross-linking task state
store.
### Testing
Using this dag:
```python
from datetime import datetime, timedelta
from airflow.providers.cncf.kubernetes.operators.pod import
KubernetesPodOperator
from airflow.sdk import DAG
with DAG(
dag_id="try_kpo",
schedule=None,
start_date=datetime(2024, 1, 1),
catchup=False,
) as dag:
run_pod = KubernetesPodOperator(
task_id="run_pod",
name="try-kpo",
namespace="default",
image="ubuntu:24.04",
cmds=["bash", "-cx"],
arguments=["sleep 60 && echo done"],
in_cluster=False,
do_xcom_push=False,
retries=2,
retry_delay=timedelta(seconds=5),
)
```
### Before my changes:
Worker killed:
<img width="1985" height="914" alt="image"
src="https://github.com/user-attachments/assets/d69f6788-3f07-4959-8506-22198966c15d";
/>
But pod still exists:
<img width="2540" height="202" alt="image"
src="https://github.com/user-attachments/assets/91236ea0-a6b6-4f4b-8e2e-c5145669f0e4";
/>
Reconnected when worker came back up:
<img width="1985" height="914" alt="image"
src="https://github.com/user-attachments/assets/61a4422c-6ce0-43c3-84dd-2838a6f0d021";
/>
### After my changes (changing to pass durable=True)
```python
run_pod = KubernetesPodOperator(
task_id="run_pod",
name="try-kpo",
namespace="default",
image="ubuntu:24.04",
cmds=["bash", "-cx"],
arguments=["sleep 60 && echo done"],
in_cluster=False,
do_xcom_push=False,
retries=2,
retry_delay=timedelta(seconds=5),
durable=True,
)
```
WOrker killed:
<img width="2544" height="988" alt="image"
src="https://github.com/user-attachments/assets/e0df6342-4b97-44b3-8a29-255bd02373df";
/>
Task store persisted:
<img width="2544" height="988" alt="image"
src="https://github.com/user-attachments/assets/761d9cdf-ce3b-4014-9ad8-902f37322c58";
/>
```shell
[Breeze:3.10.20] root@0014bf761b80:/opt/airflow$ cat
/tmp/airflow_state/ti_run_pod/pod_identifier.json
{"name": "try-kpo-vlap9a9c", "namespace": "default", "uid":
"878b321f-fb21-4779-94c4-1811f7ced720"}[Breeze:3.10.20]
```
Pod present and reconnected to via state store:
<img width="2544" height="988" alt="image"
src="https://github.com/user-attachments/assets/07a07bec-df4d-43ce-88db-901950848666";
/>
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