`external-dns` - keep DNS records in step with Kubernetes Services, Ingresses and Gateway routes

external-dns --source=SOURCE... --provider=PROVIDER [--policy=upsert-only|sync] [--registry=txt --txt-owner-id=ID]

Options you will use

--source=service|ingress|gateway-httproute: where hostnames come from
--provider=rfc2136|aws|azure|google|cloudflare...: which DNS API it writes to
--policy=upsert-only: create and update, never delete (the safe default); sync also deletes
--registry=txt --txt-owner-id=ID: a TXT record next to every record it owns, so two clusters never fight over a name
--domain-filter=lab: only names in this zone
--interval=1m: how often it reconciles

$ kubectl annotate svc web external-dns.kubernetes.io/hostname=web.lab

a LoadBalancer Service gets an A record

$ kubectl logs -n external-dns deploy/external-dns

"Adding RR: shop.lab 300 A 10.64.0.240"

Since v0.22 the annotation prefix is external-dns.kubernetes.io/ (no fallback); old manifests with external-dns.alpha.kubernetes.io/hostname are ignored unless --annotation-prefix sets the old one.

Try external-dns in a real terminal Free, in your browser - a real Ubuntu terminal to try it in, with missions that check your work.