Secondaries transfer catalog member and plain secondary zones from the
primary Service ClusterIP (stable across primary pod restarts), and BIND
derives a zone's implicit allow-notify from its primaries list. But the
primary pod's NOTIFYs egress with its *pod* IP as source — k8s Services
NAT only the inbound direction — so BIND refuses them as "refused notify
from non-primary" and replication falls back to the SOA refresh timer, a
1-hour propagation delay on every dynamic zone (external-dns RFC2136 and
dns-updater nsupdates alike).
Render an options-scope allow-notify on secondaries covering the primary
pod IP (and the transfer address, since an explicit allow-notify replaces
the primaries-derived default). The cluster controller resolves the
primary pod IP the same way it already does for seeding/also-notify, and
the existing Pod watch re-renders the ConfigMap when the pod IP changes.
unkinben