[Containerapp] az containerapp arc: Enable setup custom core dns for Openshift

[anandgmenon]

… Openshift on Arc

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[azure-client-tools-bot-prd]

⚠️Azure CLI Extensions Breaking Change Test

⚠️containerapp

rule	cmd_name	rule_message	suggest_message
⚠️ 1010 - ParaPropUpdate	containerapp arc setup-core-dns	cmd containerapp arc setup-core-dns update parameter distro: updated property choices from ['AksAzureLocal'] to ['AksAzureLocal', 'openshift']

[azure-client-tools-bot-prd]

Hi @anandgmenon,
Please write the description of changes which can be perceived by customers into HISTORY.rst.
If you want to release a new extension version, please update the version in setup.py as well.

[yonzhan]

Thank you for your contribution! We will review the pull request and get back to you soon.

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[Copilot]

Pull Request Overview

This PR adds support for custom CoreDNS setup for OpenShift clusters alongside the existing AKS support.

• Adds OpenShift-specific constants and logic to create and patch CoreDNS resources.
• Introduces new functions in _arc_utils.py for managing deployments, config maps, and DNS operator configurations on OpenShift.
• Updates CLI parameter definitions to include OpenShift as a supported distro.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/containerapp/azext_containerapp/custom.py	Adds OpenShift branch in setup_core_dns and related logging/error handling.
src/containerapp/azext_containerapp/_params.py	Updates CLI argument to include OpenShift distro with a minor typo in the help text.
src/containerapp/azext_containerapp/_constants.py	Introduces new constants for OpenShift support.
src/containerapp/azext_containerapp/_arc_utils.py	Adds multiple helper functions for creating/updating resources and patching DNS operator for OpenShift.

Comments suppressed due to low confidence (1)

src/containerapp/azext_containerapp/_arc_utils.py:637

• [nitpick] The error message appears counterintuitive; consider rephrasing it to indicate that the required key is missing (e.g., "'k4apps-default.io.server' key not found in the coredns-custom ConfigMap in kube-system namespace.").

raise ValidationError("'k4apps-default.io.server' key found in the coredns-custom ConfigMap in kube-system namespace.")

[github-actions]

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[github-actions]

• For more info about extension versioning, please refer to Extension version schema

[Juliehzl]

Please also update history.rst with releasee note for the feature. In addition, do you want to release the feature? If yes, please update version in setup.py

[zhoxing-ms]

Could you please add some test cases for these PR changes?

[anandgmenon]

Could you please add some test cases for these PR changes?

These changes are specifically targeted for container apps on arc for openshift cluster. Hence adding testcases for the same will need a openshift cluster which can be tricky. Wondering if we can skip them here

[zhoxing-ms]

/azp run

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Azure Pipelines successfully started running 2 pipeline(s).

[azclibot]

[Release] Update index.json for extension [ containerapp ] : https://dev.azure.com/msazure/One/_build/results?buildId=130273726&view=results