Feature Overview (aka. Goal Summary)

Allow the custom DNS feature to be enabled on Day-2 by modifying the Infrastructure CR, enabling ARO to migrate existing clusters to use the new in-cluster DNS functionality.

Why is this important?

ARO already has its own mechanism for implementing custom DNS. Enabling the in-cluster DNS for new installs will only partially enable this mechanism to be turned off. To get rid of it entirely, existing clusters must be switched over to use the new custom DNS functionality for core OCP.

This feature is critical for:

• Allowing ARO to deprecate their legacy custom DNS mechanism
• Enabling seamless migration of existing ARO clusters
• Consolidating DNS functionality within core OCP

Scenarios

1. Cluster admin wants to enable custom DNS on an existing ARO cluster
2. ARO team needs to migrate existing clusters from legacy DNS mechanism to the new in-cluster DNS

Acceptance Criteria

• CI - MUST be running successfully with tests automated
• Release Technical Enablement - Provide necessary release enablement details and documents
• Day-2 enablement of custom DNS via Infrastructure CR modification is functional
• Existing clusters can be migrated without disruption

Dependencies (internal and external)

1. Design details being worked on in ARO: CoreDNS Plugins in HCM WD

Open Questions

1. How do we update the pointer ignition to reference the IP address of the internal load balancer instead of api-int for fetching the ignition?

Done Checklist

• CI - CI is running, tests are automated and merged
• Release Enablement - Feature Enablement Presentation completed
• DEV - Upstream code and tests merged
• DEV - Upstream documentation merged
• DEV - Downstream build attached to advisory
• QE - Test plans in Polarion
• QE - Automated tests merged
• DOC - Downstream documentation merged