FLINK-20359 Added Owner Reference to Job Manager in native kubernetes setup

[blublinsky]

What is the purpose of the change

Flink implementation is often a part of the larger application. As a result a synchronized management - clean up of Flink resources, when a main application is deleted is important. In Kubernetes, a common approach for such clean up is usage of the owner's reference (https://kubernetes.io/docs/concepts/workloads/controllers/garbage-collection/)

This PR allows adding owner reference support to Flink Job manager

Brief change log

(for example:)

• Add configuration for owner reference
• Updated Job Manager factory to process owner's reference
• Updated Job Manager factory unit test

Verifying this change

(Please pick either of the following options)

This change added tests and can be verified as follows:

• Extended Job Manager factory unit test to validate change

Does this pull request potentially affect one of the following parts:

• The public API, i.e., is any changed class annotated with @Public(Evolving): yes

Documentation

• Does this pull request introduce a new feature? yes
• If yes, how is the feature documented? JavaDocs

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Last check on commit 6a43ad7 (Fri May 28 07:13:02 UTC 2021)

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[wangyang0918]

@blublinsky Generally, this PR could work. But I think we could make the implementation more gracefully.

• We could introduce a new Kubernetes resource in Flink KubernetesOwnerReference, similar to KubernetesToleration.
• KubernetesOwnerReference could be built from a map, which is configured via kubernetes.jobmanager.ownerref. It is a config option with map .mapType(), similar to kubernetes.jobmanager.tolerations.
• KubernetesOwnerReference could be tested separately.

[blublinsky]

We could, which creates a lot of code, which not really add clarity or simplicity. Right now it is just 9 lines of code. What is the point of creation additional class, that is doing exactly the same?

[wangyang0918]

@blublinsky Thanks for your comments.

First, I believe parsing the KubernetesOwnerReference is not the ability of KubernetesJobManagerFactory. Moving the parsing logics out could make it more testable and reusable[1]. Second, we already have the mechanism to parse the structured string to a map. It will help a lot to convert them to a KubernetesOwnerReference. Benefit from the map, we do not require the users to always set all the fields(e.g. apiVersion, blockOwnerDeletion, controller, kind, name, uid) in specific order. It will be easier to use. Last, I do not think it will introduce two much codes except for the tests.

[1]. https://flink.apache.org/contributing/code-style-and-quality-common.html#design-for-testability

[blublinsky]

@wangyang0918, thanks for the comment
"parsing the KubernetesOwnerReference is not the ability of KubernetesJobManagerFactory". I agree with this and can move this to KubernetesJobManagerParameters. this will clean up the code.
"Second, we already have the mechanism to parse the structured string to a map" - but unlike environment, owner reference is not really a map - its a list of parameters - does it make sense to convert this to the map, or positional list is good enough?

[blublinsky]

@wangyang0918
Redid the implementation based on your request. Had to move it #14512.

[xintongsong]

Closing this PR, with #14591 as the replacement.