Enable external-dns integration via per-service annotations on each generated service
Currently the MongoDB Kubernetes Operator allows specification of annotations on services created by the operator, but only annotations with the same value across all services. The external-dns operator can create DNS names based on annotations on services. In order to support external-dns integration the MongoDB Kubernetes Operator would need to allow one to specify specific annotations for each generated service.
Current spec for external access services:
# Same annotations will be applied on all services
You could consider a placeholder/substitution scheme like:
external-dns.alpha.kubernetes.io/hostname: mydb-db-<instance number>.mydns.com
Or some other way of assigning a per-service annotation that can be used by other operators such as external-dns.