[Scaleway] invalid argument: cname can not be used in root zone, you can use alias

[jgourmelen]

Bug Report: Handling of CNAME Records at Root Zone with ExternalDNS on Scaleway

Component: ExternalDNS

Configuration Summary:
ExternalDNS is configured to manage DNS records dynamically with Kubernetes resources. The settings include various DNS providers, API integrations, and specific configurations for handling DNS records.

Expected Behavior:
ExternalDNS should manage and update DNS records based on Kubernetes resource states without errors.

Observed Behavior:
The process logs indicate successful initialization and operation until it attempts to update DNS records. However, when trying to add a CNAME record at the root domain, ExternalDNS fails and exits with a fatal error.

Error Message:
level=fatal msg="scaleway-sdk-go: http error 400 Bad Request: invalid argument: cname can not be used in root zone, you can use alias"
Possible Cause:
The error suggests that ExternalDNS attempted to add a CNAME record at the root of the DNS zone, which is not permitted by DNS standards and specific provider limitations (in this case, Scaleway). DNS providers generally require an ALIAS or A/AAAA record at the root.

Impact:
This error causes ExternalDNS to crash, potentially leading to incomplete DNS management and service disruption.