core-services: Add plank config for ARM64 clusters

[LorbusChris]

This commit switches the plank config from using
default_decoration_configs to default_decoration_config_entries,
and adds ARM64 utility_images instead of the x86 ones usually used to
the arm01 build farm.

---

Note: The config updater might have to be changed so it can update the new arm64 utility image refs.

[LorbusChris]

/cc @stevekuznetsov
/cc @alvaroaleman
/cc @hongkailiu

[alvaroaleman]

Are you sure this supports regex?

[LorbusChris]

yes, at least that's what the README says: https://github.com/kubernetes/test-infra/tree/master/prow/plank

[alvaroaleman]

I think the readme is wrong: https://github.com/kubernetes/test-infra/blob/8f639d55cbd9aeeaabb4e8f35042b6b9f94d1dd6/prow/config/config.go#L567-L572

[LorbusChris]

I've changed the cluster value to hardcode arm01 for now, and also opened kubernetes/test-infra#23096

[LorbusChris]

Could anybody comment on whether the bot's automatic image ref updates would be broken by this? If so, please let me know where that code lives so I can take a look :)

[alvaroaleman]

Could anybody comment on whether the bot's automatic image ref updates would be broken by this? If so, please let me know where that code lives so I can take a look :)

It shouldn't, afaik it just does string replacements.

Is it possible to have one decoration config for the images that gets merged into all the other ones? What we have currently is annoying to read because it makes one think the config had different values there

[LorbusChris]

@alvaroaleman do you mean one decoration config containing only the utility_images that gets merged into all configs except on the arm cluster? I don't know if that's supported - I guess it is but I'd rather do such optimizations later.

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alvaroaleman, LorbusChris

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[openshift-ci]

@LorbusChris: Updated the config configmap in namespace ci at cluster app.ci using the following files:

• key config.yaml using file core-services/prow/02_config/_config.yaml

Details

In response to this:

This commit switches the plank config from using
default_decoration_configs to default_decoration_config_entries,
and adds ARM64 utility_images instead of the x86 ones usually used to
the arm01 build farm.

---

Note: The config updater might have to be changed so it can update the new arm64 utility image refs.

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