DNS records for service do not appear to be deleted

[gtomilko]

What happened: I have Headless service annotated with external-dns entries:

apiVersion: v1
kind: Service
metadata:
  annotations:
    external-dns.alpha.kubernetes.io/hostname: host.domain.edu
    external-dns.alpha.kubernetes.io/ttl: "180"
  name: cplane-for-dns
  namespace: kube-system
spec:
  clusterIP: None
  clusterIPs:
  - None
  internalTrafficPolicy: Cluster
  ipFamilies:
  - IPv4
  ipFamilyPolicy: SingleStack
  ports:
  - name: api-port
    port: 6443
    protocol: TCP
    targetPort: 6443
  selector:
    component: kube-apiserver
  sessionAffinity: None
  type: ClusterIP

External-dns publishes all dns records for this service as it should:

level=info msg="Adding RR: host.domain.edu 180 A 192.168.50.177"
level=info msg="Adding RR: host.domain.edu 180 A 192.168.50.202"
level=info msg="Adding RR: host.domain.edu 180 A 192.168.50.248"
level=info msg="Adding RR: host.domain.edu 0 TXT \"heritage=external-dns,external-dns/owner=default,external-dns/resource=service/kube-system/cplane-for-dns\""
level=info msg="Adding RR: a-host.domain.edu 0 TXT \"heritage=external-dns,external-dns/owner=default,external-dns/resource=service/kube-system/cplane-for-dns\""
level=info msg="Adding RR: host.domain.edu 180 A 192.168.50.177"
level=info msg="Adding RR: host.domain.edu 180 A 192.168.50.202"
level=info msg="Adding RR: host.domain.edu 180 A 192.168.50.248"
level=info msg="Adding RR: host.domain.edu 0 TXT \"heritage=external-dns,external-dns/owner=default,external-dns/resource=service/kube-system/cplane-for-dns\""
level=info msg="Adding RR: a-host.domain.edu 0 TXT \"heritage=external-dns,external-dns/owner=default,external-dns/resource=service/kube-system/cplane-for-dns\""

What you expected to happen:
As my nodes with this service get created and deleted I expect dns records to be created and removed. But records get created and never removed. Policy set to sync.

Here is external-dns config:

apiVersion: v1
kind: Pod
metadata:
  labels:
    app.kubernetes.io/instance: external-dns
    app.kubernetes.io/name: external-dns
    pod-template-hash: 664f757fc7
  name: external-dns-664f757fc7-6glvw
  namespace: external-dns
spec:
  containers:
  - args:
    - --log-level=info
    - --log-format=text
    - --interval=1m
    - --source=service
    - --source=ingress
    - --policy=sync
    - --registry=txt
    - --provider=rfc2136
    - --rfc2136-host=192.168.96.5
    - --rfc2136-port=53
    - --rfc2136-zone=domain.edu
    - --rfc2136-insecure
    image: my-internal-registry/internal-infrastructure/external-dns:v0.13.2
    imagePullPolicy: IfNotPresent
    livenessProbe:
      failureThreshold: 2
      httpGet:
        path: /healthz
        port: http
        scheme: HTTP
      initialDelaySeconds: 10
      periodSeconds: 10
      successThreshold: 1
      timeoutSeconds: 5
    name: external-dns
    ports:
    - containerPort: 7979
      name: http
      protocol: TCP
    readinessProbe:
      failureThreshold: 6
      httpGet:
        path: /healthz
        port: http
        scheme: HTTP
      initialDelaySeconds: 5
      periodSeconds: 10
      successThreshold: 1
      timeoutSeconds: 5
    resources: {}
    securityContext:
      capabilities:
        drop:
        - ALL
      readOnlyRootFilesystem: true
      runAsNonRoot: true
      runAsUser: 65534
    terminationMessagePath: /dev/termination-log
    terminationMessagePolicy: File
    volumeMounts:
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: kube-api-access-dxpk2
      readOnly: true
  dnsPolicy: ClusterFirst
  enableServiceLinks: true
  nodeName: gc-dev-dev-worker-81f8f675-ph82s
  preemptionPolicy: PreemptLowerPriority
  priority: 0
  restartPolicy: Always
  schedulerName: default-scheduler
  securityContext:
    fsGroup: 65534
  serviceAccount: external-dns
  serviceAccountName: external-dns
  terminationGracePeriodSeconds: 30
  tolerations:
  - effect: NoExecute
    key: node.kubernetes.io/not-ready
    operator: Exists
    tolerationSeconds: 300
  - effect: NoExecute
    key: node.kubernetes.io/unreachable
    operator: Exists
    tolerationSeconds: 300
  volumes:
  - name: kube-api-access-dxpk2
    projected:
      defaultMode: 420
      sources:
      - serviceAccountToken:
          expirationSeconds: 3607
          path: token
      - configMap:
          items:
          - key: ca.crt
            path: ca.crt
          name: kube-root-ca.crt
      - downwardAPI:
          items:
          - fieldRef:
              apiVersion: v1
              fieldPath: metadata.namespace
            path: namespace

Kubernetes engine Rancher/RKE2
ExternalDns version: 0.13.2
DNS provider: rfc2136 , EfficientIP SOLIDserver/Bind

Please advise (((

[gtomilko]

Figured out, zone transfer was disabled on bind server