External DNS

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Automatic DNS management for agentgateway

External DNS automatically manages DNS records for Kubernetes resources. Use it to automatically create DNS records for agentgateway endpoints.

Why use External DNS with agentgateway?

Automatic DNS - DNS records created automatically from Gateway/Service resources
Multiple providers - AWS Route53, Google Cloud DNS, Cloudflare, Azure DNS, and more
Sync on change - Records updated when resources change
TTL management - Configurable DNS TTL

Before you begin

Install External DNS for your cloud provider. Example for AWS Route53:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: external-dns
spec:
  selector:
    matchLabels:
      app: external-dns
  template:
    metadata:
      labels:
        app: external-dns
    spec:
      serviceAccountName: external-dns
      containers:
      - name: external-dns
        image: registry.k8s.io/external-dns/external-dns:v0.14.0
        args:
        - --source=gateway-httproute
        - --provider=aws
        - --aws-zone-type=public
        - --registry=txt
        - --txt-owner-id=my-cluster

Gateway API integration

External DNS can read hostnames from Gateway resources:

apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: agentgateway
spec:
  gatewayClassName: agentgateway
  listeners:
  - name: https
    protocol: HTTPS
    port: 443
    hostname: "ai.example.com"  # External DNS creates this record
    tls:
      mode: Terminate
      certificateRefs:
      - name: ai-example-com-tls  # A TLS Secret for ai.example.com

An HTTPS listener needs a tls block with a certificate. To issue and renew the certificate automatically, see the cert-manager integration.

External DNS automatically:

Watches for Gateway resources
Extracts the hostname
Creates/updates DNS records pointing to the Gateway’s external IP

HTTPRoute hostnames

External DNS also reads hostnames from HTTPRoute:

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: ai-api
  annotations:
    external-dns.alpha.kubernetes.io/hostname: api.example.com
spec:
  parentRefs:
  - name: agentgateway
  hostnames:
  - "api.example.com"
  rules:
  - backendRefs:
    - name: agentgateway
      port: 3000

Annotations

Control External DNS behavior with annotations:

metadata:
  annotations:
    # Set specific hostname
    external-dns.alpha.kubernetes.io/hostname: ai.example.com
    # Set TTL
    external-dns.alpha.kubernetes.io/ttl: "300"
    # Use specific target
    external-dns.alpha.kubernetes.io/target: 1.2.3.4

Provider examples

Cloudflare

args:
- --source=gateway-httproute
- --provider=cloudflare
- --cloudflare-proxied  # Enable Cloudflare proxy
env:
- name: CF_API_TOKEN
  valueFrom:
    secretKeyRef:
      name: cloudflare-credentials
      key: api-token

Google Cloud DNS

args:
- --source=gateway-httproute
- --provider=google
- --google-project=my-project

Azure DNS

args:
- --source=gateway-httproute
- --provider=azure
- --azure-resource-group=my-rg
- --azure-subscription-id=my-sub-id

Learn more

cert-manager

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