Add priorityClassName support

[YossiTamari]

Official Helm Chart version

1.2.0

Apache Airflow version

2.1.4

Kubernetes Version

1.21.2

Helm Chart configuration

No response

Docker Image customisations

No response

What happened

No response

What you expected to happen

No response

How to reproduce

No response

Anything else

It's currently impossible to assign a priorityClassName to the Airflow containers.
Seems like a very useful feature to ensure that the Airflow infrastructure has higher priority than "regular" pods.

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[boring-cyborg]

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[subkanthi]

I can take on this, thoughts on the priorityClasses would be useful.
Simple proposal would be to define 3 priority classes(high, medium, low) and then assign it to different deployments. Maybe airflow-migration takes high priority.

kind: PriorityClass
metadata:
  name: high-priority-nonpreempting
value: 1000000
preemptionPolicy: Never
globalDefault: false
description: "This priority class will not cause other pods to be preempted."```

[YossiTamari]

Hi @subkanthi, thanks for taking this. My request was only to add support for assigning priorities in values.yaml, not necessarily for creating priorities or assigning them by default (Same thing as affinity, which has a default empty value).

[potiuk]

assigned it @subkanthi