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233 lines
6.7 KiB
Markdown
233 lines
6.7 KiB
Markdown
# DigitalOcean DNS
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This tutorial describes how to setup ExternalDNS for usage within a Kubernetes cluster using DigitalOcean DNS.
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Make sure to use **>=0.4.2** version of ExternalDNS for this tutorial.
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## Creating a DigitalOcean DNS zone
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If you want to learn about how to use DigitalOcean's DNS service read the following tutorial series:
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[An Introduction to Managing DNS](https://www.digitalocean.com/community/tutorial_series/an-introduction-to-managing-dns), and specifically [How To Set Up a Host Name with DigitalOcean DNS](https://www.digitalocean.com/community/tutorials/how-to-set-up-a-host-name-with-digitalocean)
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Create a new DNS zone where you want to create your records in. Let's use `example.com` as an example here.
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## Creating DigitalOcean Credentials
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Generate a new personal token by going to [the API settings](https://cloud.digitalocean.com/settings/api/tokens) or follow [How To Use the DigitalOcean API v2](https://www.digitalocean.com/community/tutorials/how-to-use-the-digitalocean-api-v2) if you need more information. Give the token a name and choose read and write access. The token needs to be passed to ExternalDNS so make a note of it for later use.
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The environment variable `DO_TOKEN` will be needed to run ExternalDNS with DigitalOcean.
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## Deploy ExternalDNS
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Connect your `kubectl` client to the cluster you want to test ExternalDNS with.
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Begin by creating a Kubernetes secret to securely store your DigitalOcean API key. This key will enable ExternalDNS to authenticate with DigitalOcean:
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```shell
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kubectl create secret generic DO_TOKEN --from-literal=DO_TOKEN=YOUR_DIGITALOCEAN_API_KEY
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```
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Ensure to replace YOUR_DIGITALOCEAN_API_KEY with your actual DigitalOcean API key.
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Then apply one of the following manifests file to deploy ExternalDNS.
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## Using Helm
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Create a values.yaml file to configure ExternalDNS to use DigitalOcean as the DNS provider. This file should include the necessary environment variables:
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```shell
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provider:
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name: digitalocean
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env:
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- name: DO_TOKEN
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valueFrom:
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secretKeyRef:
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name: DO_TOKEN
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key: DO_TOKEN
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```
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### Manifest (for clusters without RBAC enabled)
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```yaml
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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name: external-dns
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spec:
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replicas: 1
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selector:
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matchLabels:
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app: external-dns
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strategy:
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type: Recreate
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template:
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metadata:
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labels:
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app: external-dns
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spec:
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containers:
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- name: external-dns
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image: registry.k8s.io/external-dns/external-dns:v0.15.0
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args:
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- --source=service # ingress is also possible
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- --domain-filter=example.com # (optional) limit to only example.com domains; change to match the zone created above.
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- --provider=digitalocean
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env:
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- name: DO_TOKEN
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valueFrom:
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secretKeyRef:
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name: DO_TOKEN
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key: DO_TOKEN
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```
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### Manifest (for clusters with RBAC enabled)
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```yaml
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apiVersion: v1
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kind: ServiceAccount
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metadata:
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name: external-dns
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRole
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metadata:
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name: external-dns
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rules:
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- apiGroups: [""]
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resources: ["services","endpoints","pods"]
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verbs: ["get","watch","list"]
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- apiGroups: ["extensions","networking.k8s.io"]
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resources: ["ingresses"]
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verbs: ["get","watch","list"]
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- apiGroups: [""]
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resources: ["nodes"]
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verbs: ["list"]
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRoleBinding
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metadata:
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name: external-dns-viewer
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roleRef:
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apiGroup: rbac.authorization.k8s.io
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kind: ClusterRole
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name: external-dns
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subjects:
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- kind: ServiceAccount
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name: external-dns
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namespace: default
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---
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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name: external-dns
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spec:
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replicas: 1
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selector:
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matchLabels:
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app: external-dns
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strategy:
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type: Recreate
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template:
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metadata:
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labels:
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app: external-dns
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spec:
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serviceAccountName: external-dns
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containers:
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- name: external-dns
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image: registry.k8s.io/external-dns/external-dns:v0.15.0
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args:
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- --source=service # ingress is also possible
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- --domain-filter=example.com # (optional) limit to only example.com domains; change to match the zone created above.
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- --provider=digitalocean
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env:
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- name: DO_TOKEN
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valueFrom:
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secretKeyRef:
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name: DO_TOKEN
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key: DO_TOKEN
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```
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## Deploying an Nginx Service
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Create a service file called 'nginx.yaml' with the following contents:
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```yaml
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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name: nginx
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spec:
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replicas: 1
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selector:
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matchLabels:
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app: nginx
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template:
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metadata:
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labels:
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app: nginx
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spec:
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containers:
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- image: nginx
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name: nginx
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ports:
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- containerPort: 80
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---
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apiVersion: v1
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kind: Service
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metadata:
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name: nginx
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annotations:
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external-dns.alpha.kubernetes.io/hostname: my-app.example.com
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spec:
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selector:
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app: nginx
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type: LoadBalancer
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ports:
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- protocol: TCP
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port: 80
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targetPort: 80
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```
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Note the annotation on the service; use the same hostname as the DigitalOcean DNS zone created above.
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ExternalDNS uses this annotation to determine what services should be registered with DNS. Removing the annotation will cause ExternalDNS to remove the corresponding DNS records.
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Create the deployment and service:
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```console
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$ kubectl create -f nginx.yaml
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```
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Depending where you run your service it can take a little while for your cloud provider to create an external IP for the service.
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Once the service has an external IP assigned, ExternalDNS will notice the new service IP address and synchronize the DigitalOcean DNS records.
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## Verifying DigitalOcean DNS records
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Check your [DigitalOcean UI](https://cloud.digitalocean.com/networking/domains) to view the records for your DigitalOcean DNS zone.
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Click on the zone for the one created above if a different domain was used.
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This should show the external IP address of the service as the A record for your domain.
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## Cleanup
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Now that we have verified that ExternalDNS will automatically manage DigitalOcean DNS records, we can delete the tutorial's example:
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```
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$ kubectl delete service -f nginx.yaml
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$ kubectl delete service -f externaldns.yaml
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```
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## Advanced Usage
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### API Page Size
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If you have a large number of domains and/or records within a domain, you may encounter API
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rate limiting because of the number of API calls that external-dns must make to the DigitalOcean API to retrieve
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the current DNS configuration during every reconciliation loop. If this is the case, use the
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`--digitalocean-api-page-size` option to increase the size of the pages used when querying the DigitalOcean API.
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(Note: external-dns uses a default of 50.)
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