Setting up ExternalDNS for Services on Cloudflare¶
This tutorial describes how to setup ExternalDNS for usage within a Kubernetes cluster using Cloudflare DNS.
Make sure to use >=0.4.2 version of ExternalDNS for this tutorial.
Creating a Cloudflare DNS zone¶
We highly recommend to read this tutorial if you haven’t used Cloudflare before:
Create a Cloudflare account and add a website
Creating Cloudflare Credentials¶
Snippet from Cloudflare - Getting Started:
Cloudflare’s API exposes the entire Cloudflare infrastructure via a standardized programmatic interface. Using Cloudflare’s API, you can do just about anything you can do on cloudflare.com via the customer dashboard.
The Cloudflare API is a RESTful API based on HTTPS requests and JSON responses. If you are registered with Cloudflare, you can obtain your API key from the bottom of the “My Account” page, found here: Go to My account.
API Token will be preferred for authentication if CF_API_TOKEN environment variable is set.
Otherwise CF_API_KEY and CF_API_EMAIL should be set to run ExternalDNS with Cloudflare.
You may provide the Cloudflare API token through a file by setting the
CF_API_TOKEN="file:/path/to/token".
Note. The CF_API_KEY and CF_API_EMAIL should not be present, if you are using a CF_API_TOKEN.
When using API Token authentication, the token should be granted Zone Read, DNS Edit privileges, and access to All zones.
If you would like to further restrict the API permissions to a specific zone (or zones), you also need to use the --zone-id-filter so that the underlying API requests only access the zones that you explicitly specify, as opposed to accessing all zones.
Throttling¶
Cloudflare API has a global rate limit of 1,200 requests per five minutes. Running several fast polling ExternalDNS instances in a given account can easily hit that limit. The AWS Provider docs has some recommendations that can be followed here too, but in particular, consider passing --cloudflare-dns-records-per-page with a high value (maximum is 5,000).
Deploy ExternalDNS¶
Connect your kubectl client to the cluster you want to test ExternalDNS with.
Begin by creating a Kubernetes secret to securely store your CloudFlare API key. This key will enable ExternalDNS to authenticate with CloudFlare:
kubectl create secret generic cloudflare-api-key --from-literal=apiKey=YOUR_API_KEY --from-literal=email=YOUR_CLOUDFLARE_EMAIL
And for API Token it should look like :
Ensure to replace YOUR_API_KEY with your actual CloudFlare API key and YOUR_CLOUDFLARE_EMAIL with the email associated with your CloudFlare account.
Then apply one of the following manifests file to deploy ExternalDNS.
Using Helm¶
Create a values.yaml file to configure ExternalDNS to use CloudFlare as the DNS provider. This file should include the necessary environment variables:
provider:
name: cloudflare
env:
- name: CF_API_KEY
valueFrom:
secretKeyRef:
name: cloudflare-api-key
key: apiKey
- name: CF_API_EMAIL
valueFrom:
secretKeyRef:
name: cloudflare-api-key
key: email
Use this in your values.yaml, if you are using API Token:
provider:
name: cloudflare
env:
- name: CF_API_TOKEN
valueFrom:
secretKeyRef:
name: cloudflare-api-key
key: apiKey
Finally, install the ExternalDNS chart with Helm using the configuration specified in your values.yaml file:
Manifest (for clusters without RBAC enabled)¶
apiVersion: apps/v1
kind: Deployment
metadata:
name: external-dns
spec:
strategy:
type: Recreate
selector:
matchLabels:
app: external-dns
template:
metadata:
labels:
app: external-dns
spec:
containers:
- name: external-dns
image: registry.k8s.io/external-dns/external-dns:v0.14.1
args:
- --source=service # ingress is also possible
- --domain-filter=example.com # (optional) limit to only example.com domains; change to match the zone created above.
- --zone-id-filter=023e105f4ecef8ad9ca31a8372d0c353 # (optional) limit to a specific zone.
- --provider=cloudflare
- --cloudflare-proxied # (optional) enable the proxy feature of Cloudflare (DDOS protection, CDN...)
- --cloudflare-dns-records-per-page=5000 # (optional) configure how many DNS records to fetch per request
env:
- name: CF_API_KEY
valueFrom:
secretKeyRef:
name: cloudflare-api-key
key: apiKey
- name: CF_API_EMAIL
valueFrom:
secretKeyRef:
name: cloudflare-api-key
key: email
Manifest (for clusters with RBAC enabled)¶
apiVersion: v1
kind: ServiceAccount
metadata:
name: external-dns
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: external-dns
rules:
- apiGroups: [""]
resources: ["services","endpoints","pods"]
verbs: ["get","watch","list"]
- apiGroups: ["extensions","networking.k8s.io"]
resources: ["ingresses"]
verbs: ["get","watch","list"]
- apiGroups: [""]
resources: ["nodes"]
verbs: ["list", "watch"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: external-dns-viewer
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: external-dns
subjects:
- kind: ServiceAccount
name: external-dns
namespace: default
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: external-dns
spec:
strategy:
type: Recreate
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:v0.14.1
args:
- --source=service # ingress is also possible
- --domain-filter=example.com # (optional) limit to only example.com domains; change to match the zone created above.
- --zone-id-filter=023e105f4ecef8ad9ca31a8372d0c353 # (optional) limit to a specific zone.
- --provider=cloudflare
- --cloudflare-proxied # (optional) enable the proxy feature of Cloudflare (DDOS protection, CDN...)
- --cloudflare-dns-records-per-page=5000 # (optional) configure how many DNS records to fetch per request
env:
- name: CF_API_KEY
valueFrom:
secretKeyRef:
name: cloudflare-api-key
key: apiKey
- name: CF_API_EMAIL
valueFrom:
secretKeyRef:
name: cloudflare-api-key
key: email
Deploying an Nginx Service¶
Create a service file called ‘nginx.yaml’ with the following contents:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- image: nginx
name: nginx
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx
annotations:
external-dns.alpha.kubernetes.io/hostname: example.com
external-dns.alpha.kubernetes.io/ttl: "120" #optional
spec:
selector:
app: nginx
type: LoadBalancer
ports:
- protocol: TCP
port: 80
targetPort: 80
Note the annotation on the service; use the same hostname as the Cloudflare DNS zone created above. The annotation may also be a subdomain
of the DNS zone (e.g. ‘www.example.com’).
By setting the TTL annotation on the service, you have to pass a valid TTL, which must be 120 or above.
This annotation is optional, if you won’t set it, it will be 1 (automatic) which is 300.
For Cloudflare proxied entries, set the TTL annotation to 1 (automatic), or do not set it.
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.
Create the deployment and service:
Depending where you run your service it can take a little while for your cloud provider to create an external IP for the service.
Once the service has an external IP assigned, ExternalDNS will notice the new service IP address and synchronize
the Cloudflare DNS records.
Verifying Cloudflare DNS records¶
Check your Cloudflare dashboard to view the records for your Cloudflare DNS zone.
Substitute the zone for the one created above if a different domain was used.
This should show the external IP address of the service as the A record for your domain.
Cleanup¶
Now that we have verified that ExternalDNS will automatically manage Cloudflare DNS records, we can delete the tutorial’s example:
Setting cloudflare-proxied on a per-ingress basis¶
Using the external-dns.alpha.kubernetes.io/cloudflare-proxied: "true" annotation on your ingress, you can specify if the proxy feature of Cloudflare should be enabled for that record. This setting will override the global --cloudflare-proxied setting.