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External DNS

External DNS

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

Why use External DNS with Agent Gateway?

  • 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

Prerequisites

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

External DNS automatically:

  1. Watches for Gateway resources
  2. Extracts the hostname
  3. 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

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