How to use ExternalDNS for automatic DNS?

Question

Accepted Answer

**ExternalDNS** — automatic creation of DNS records from K8s Service/Ingress.

**Installation:**
```bash
helm repo add bitnami https://charts.bitnami.com/bitnami
helm install external-dns bitnami/external-dns \
  --namespace kube-system \
  --set provider=aws \
  --set aws.zoneId=Z1234567890 \
  --set sources="{ingress,service}"
```

**Ingress with annotation:**
```yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp
  annotations:
    external-dns.alpha.kubernetes.io/hostname: myapp.example.com
    external-dns.alpha.kubernetes.io/ttl: "60"
    external-dns.alpha.kubernetes.io/aws-target-type: alb
spec:
  ingressClassName: nginx
  rules:
    - host: myapp.example.com
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: myapp
                port:
                  number: 80
```

**Service with annotation:**
```yaml
apiVersion: v1
kind: Service
metadata:
  name: myapp
  annotations:
    external-dns.alpha.kubernetes.io/hostname: myapp.example.com
spec:
  type: LoadBalancer
  ports:
    - port: 80
  selector:
    app: myapp
```

**Supported providers:** AWS Route53, Google Cloud DNS, Azure DNS, Cloudflare, CoreDNS.

DevOps: How to use ExternalDNS for automatic DNS?