fix: delete pod when base container completes

[jonathan-ostrander]

Closes #39693

Special logic was added to KubernetesPodOperator's lifecycle to handle the case where an istio proxy sidecar is running and preventing the pod from completing, but this logic should have been applied more generally to handle when multiple containers are ran in the pod. The new behavior considers the pod completed if the container matching the base name has completed.

The istio-specific logic has been removed because it is no longer used.

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[jedcunningham]

Did you test on_finish_action="keep_pod"? We don't always delete the pods. I doubt we can do away with our istio handling like this, and I suspect that got broken somehow recently.

[jedcunningham]

I did a little digging, and that scenario was never covered when the feature was added in #33306 😞. I don't think we want to leave these pods still running.

[jedcunningham]

Yeah, it's tough to 1) do it generally 2) not delete pods and 3) not leave the pods running. That's why istio has (or tried to have it turns out) special handling.

I'm actually excited about the new(ish) sidecar support in k8s. It should make this situation a lot easier to tackle. Istio does have support for it also via ENABLE_NATIVE_SIDECARS. I'm not sure how well Airflow tolerates that though, I just know I haven't personally tried it yet.

[jonathan-ostrander]

@jedcunningham I'm not sure I understand your point about OnFinishAction.KEEP_POD or why the istio side car needs to be treated as a special case. Shouldn't that finish action be respected regardless of what's running in the pod? This doesn't change the behavior of KubernetesPodOperator#process_pod_deletion at all. It just changes the condition for a pod to be considered completed.

I'm also excited by the introduction of sidecars, but sadly the GKE cluster that my team has airflow deployed on is currently on k8s version 1.27.x and our infra team doesn't have plans to upgrade to 1.29.x for a couple of months... We have a workaround which is to just enable the istio proxy (or just name the sidecar container istio-proxy) but this feels hacky considering we don't need istio.

[dirrao]

In the case of additional sidecars, the additional sidecars (i.e. Splunk) have to wait for the completion of the base container and do self-kill. If not, we need to kill the additional sidecars after the timeout. Are we handling that scenario?

[ashb]

Maybe it's elsewhere in the code path so doesn't show up in the diff, but where do we terminate the other containers in the pod?

[jonathan-ostrander]

@ashb @dirrao That should happen when the pod is deleted. According to the k8s docs, when a pod is marked for deletion the containers in the pod are issued a TERM with a 30 second grace period.

[dirrao]

closes: #39625

[amoghrajesh]

Do we not have istio support anymore?
Can we instead also try using sidecar containers in. new k8s or by using the container lifecycle exit hooks?

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