Install ExternalDNS on Google Kubernetes Engine (GKE)

ExternalDNS is the component that bridges your cluster and your DNS provider — in this case, Google Cloud DNS. Rather than managing DNS records by hand, ExternalDNS watches your ingresses and services and configures them automatically.

Create a service account to allow ExternalDNS to interact with Google Cloud DNS:

SERVICE_ACCOUNT_NAME="external-dns"
SERVICE_ACCOUNT_EMAIL="$SERVICE_ACCOUNT_NAME@$PROJECT_ID.iam.gserviceaccount.com"

# Create service account
gcloud iam service-accounts create external-dns \
  --display-name "external-dns"

# Grant DNS admin permissions
gcloud projects add-iam-policy-binding $PROJECT_ID \
  --member "serviceAccount:external-dns@$PROJECT_ID.iam.gserviceaccount.com" \
  --role "roles/dns.admin"

gcloud iam service-accounts add-iam-policy-binding \
  external-dns@$PROJECT_ID.iam.gserviceaccount.com \
  --role "roles/iam.workloadIdentityUser" \
  --member "serviceAccount:$PROJECT_ID.svc.id.goog[external-dns/external-dns]"

Deploy ExternalDNS

With the service account in place, deploy ExternalDNS using Helm:

helm repo add external-dns https://kubernetes-sigs.github.io/external-dns/
helm repo update

helm upgrade external-dns external-dns/external-dns \
  --install                                         \
  --create-namespace                                \
  --namespace external-dns                          \
  --set provider.name=google                        \
  --set google.project=$PROJECT_ID                  \
  --set serviceAccount.annotations."iam\.gke\.io/gcp-service-account"=external-dns@${PROJECT_ID}.iam.gserviceaccount.com \
  --set "sources[0]=service"                        \
  --set "sources[1]=ingress"                        \
  --set policy=sync                                 \
  --wait

The setup allows us to test ExternalDNS with a service :

apiVersion: v1
kind: Service
metadata:
  name: example-service
  namespace: example
  annotations:
    external-dns.alpha.kubernetes.io/hostname: example.mydomain.com
spec:
  type: LoadBalancer
  ports:
  - port: 80
  selector:
    app: example-app

References

Continue to Part III — Ingress NGINX.

Keywords : Kubernetes, Google Kubernetes Engine, GKE, DNS, ExternalDNS