External DNS

• https://github.com/kubernetes-sigs/external-dns
• ExternalDNS allows you to manage DNS records dynamically via Kubernetes Resources (DNS-provider-agnostic).
• When an Ingress or a Service object with a DNS annotation (external-dns.alpha.kubernetes.io/hostname) is created, DNS records are automatically registered in the Zone File of the name server managing that domain in the cloud provider
• The External DNS Controller sync your Ingress/Service resource with the cloud provider

Service Account

• The External DNS controller pods need an SA that grants permissions to manage the DNS records in the cloud provider

• Azure

• New DNS hosts are added to DNS Zone

• External DNS controller needs permissions by means of a User-assigned Managed Identity to manage DNS records in Azure

• AWS

• The SA associated with an IAM role (IRSA)
• The role grants access to Route 53 service

Annotations

• Annotations for Ingress and Service objects are exactly the same

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ing
  annotations:
    # The "A" Records are added to the HostedZone
    # The "A" Records will point to the LoadBalancer's IP
    # TXT records are also added
    external-dns.alpha.kubernetes.io/hostname: foo.hvitoi.com, bar.hvitoi.com
    external-dns.alpha.kubernetes.io/ttl: 10
spec:
  ingressClassName: my-ingress-class
  defaultBackend:
    service:
      name: my-svc-nodeport
      port:
        number: 80