[AIRFLOW-6504] Allow specifying configmap for Airflow Local Setting

[kaxil]

Currently airflow.cfg file can be passed via ConfigMap using airflow_configmap under [kubernetes] section setting.

We want to be able to specify airflow_local_settings.py via configmap too so that the Kubernetes Worker has this file. We need airflow_local_settings.py to specify pod_mutation_hook.

Without that currently, if we are using KubernetesExecutor and have a task with KubernetesPodOperator, it will inherit and change Pod using pod_mutation_hook

---

Issue link: AIRFLOW-6504

• Description above provides context of the change
• Commit message/PR title starts with [AIRFLOW-NNNN]. AIRFLOW-NNNN = JIRA ID^*
• Unit tests coverage for changes (not needed for documentation changes)
• Commits follow "How to write a good git commit message"
• Relevant documentation is updated including usage instructions.
• I will engage committers as explained in Contribution Workflow Example.

^* For document-only changes commit message can start with [AIRFLOW-XXXX].

---

In case of fundamental code change, Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in UPDATING.md.
Read the Pull Request Guidelines for more information.

[codecov-io]

Codecov Report

Merging #7097 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #7097      +/-   ##
==========================================
+ Coverage   85.15%   85.15%   +<.01%     
==========================================
  Files         680      680              
  Lines       38824    38832       +8     
==========================================
+ Hits        33061    33069       +8     
  Misses       5763     5763

Impacted Files	Coverage Δ
airflow/kubernetes/worker_configuration.py	99.29% <100%> (+0.03%)	⬆️
airflow/executors/kubernetes_executor.py	57.57% <100%> (+0.09%)	⬆️
airflow/operators/postgres_operator.py	100% <0%> (ø)	⬆️
airflow/utils/sqlalchemy.py	96.66% <0%> (ø)	⬆️
airflow/hooks/dbapi_hook.py	91.73% <0%> (ø)	⬆️
airflow/hooks/postgres_hook.py	94.36% <0%> (ø)	⬆️
airflow/jobs/backfill_job.py	91.88% <0%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update fe20ef6...a4f961b. Read the comment docs.

[kristof-mattei]

Hello @kaxil

Can you elaborate on why you would want to call pod_mutating_hook inside of a newly launched pod?

[kaxil]

Hello @kaxil

Can you elaborate on why you would want to call pod_mutating_hook inside of a newly launched pod?

We set tolerations and affinity inside the pod_mutation_hook for the PODs launched by KubernetesPodOperator and KuberneteExecutor. Without this PR, if we are using KubernetesExecutor and have a task with KubernetesPodOperator, the k8s worker pod won't have airflow_local_settings file and so tolerations and affinity won't be applied there.