KEP-4969: Cluster Domain Downward API

[nightkr]

• One-line PR description: Initial KEP draft

• Issue link: Cluster Domain Downward API #4969

• Other comments:

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[lfrancke]

just two minor nitpicks/typos

[lfrancke]

Suggested change

	Currently there is no way for cluster workloads to query for this domain name,
	leaving them either use relative domain names or take it as manual configuration.
	Currently, there is no way for cluster workloads to query this domain name,
	leaving them to either use relative domain names or configure it manually.

[nightkr]

6c655bf

I left "query for this" as-is, because I read the revised variant as "ask what the domain name (that I already know) means" rather than "ask what the domain name is".

[lfrancke]

Suggested change

	This KEP proposes adding a new Downward API for that workloads can use to request it.
	This KEP proposes adding a new Downward API that workloads can use to request it.

[nightkr]

6c655bf

[adrianmoisey]

I guess this is out of scope of this KEP, but I guess this change sets a precedent of other configs that could be passed down into the Pod.
I wonder if someone with more experience than me has an idea/vision of what that could look like, which may then determine what name to decide on?

[nightkr]

Looking forward, I suspect that both cases will become relevant eventually. This property just occupies an awkward spot since it doesn't really have one clean owner.

[adrianmoisey]

/ok-to-test

[k8s-ci-robot]

@nightkr: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-enhancements-verify	a878d62	link	true	/test pull-enhancements-verify

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