DEV Community

Alex Spinov
Alex Spinov

Posted on

ExternalDNS Has a Free API — Here's How to Automate DNS Management

#kubernetes #dns #devops #automation

ExternalDNS: Automate DNS for Kubernetes Services

Every DevOps engineer knows the pain: deploy a new service, then manually update DNS records. ExternalDNS eliminates this entirely by automatically configuring DNS providers (Route53, CloudFlare, Google DNS) based on Kubernetes resources.

What ExternalDNS Does

ExternalDNS watches Kubernetes Services and Ingresses, then automatically creates DNS records in your provider. Deploy a LoadBalancer service with an annotation — DNS record appears in seconds.

apiVersion: v1
kind: Service
metadata:
  name: my-app
  annotations:
    external-dns.alpha.kubernetes.io/hostname: app.example.com
spec:
  type: LoadBalancer
  ports:
    - port: 80
  selector:
    app: my-app
Enter fullscreen mode Exit fullscreen mode

The Free API (Kubernetes CRDs)

ExternalDNS uses Kubernetes-native CRDs as its API. You interact through standard kubectl commands:

# Check what DNS records ExternalDNS manages
kubectl get dnsendpoints -A

# Create a custom DNS record
cat <<EOF | kubectl apply -f -
apiVersion: externaldns.k8s.io/v1alpha1
kind: DNSEndpoint
metadata:
  name: custom-record
spec:
  endpoints:
  - dnsName: api.example.com
    recordTTL: 300
    recordType: A
    targets:
    - 1.2.3.4
EOF
Enter fullscreen mode Exit fullscreen mode

Supported Providers (50+)

  • AWS Route53 — most popular, supports alias records
  • CloudFlare — free tier friendly, proxied records
  • Google Cloud DNS — native GKE integration
  • Azure DNS — works with AKS
  • DigitalOcean — simple setup
  • Infoblox, PowerDNS, CoreDNS — on-prem options

Real-World Use Case

A startup running 200 microservices on EKS was spending 2 hours daily on DNS updates. After deploying ExternalDNS with Route53, DNS updates became automatic. Zero manual work. Zero DNS drift.

Quick Start 

helm repo add external-dns https://kubernetes-sigs.github.io/external-dns/
helm install external-dns external-dns/external-dns \
  --set provider=aws \
  --set policy=sync \
  --set registry=txt \
  --set txtOwnerId=my-cluster
Enter fullscreen mode Exit fullscreen mode

Key Features

Feature Details
Providers 50+ DNS providers
Sources Services, Ingress, Istio, Contour, F5
Policies sync, upsert-only, create-only
Registry TXT records for ownership tracking
Filtering Namespace, annotation, domain filters

Resources

Need automated data collection for your infrastructure monitoring? Check out my web scraping actors on Apify or email me at spinov001@gmail.com for custom DevOps automation solutions.

Top comments (0)