General deployment with Cloudflare integration

In this guide, we will demonstrate how to configure k8gb to integrate with Cloudflare for automated zone delegation configuration.

Initial setup

As a prerequisite, we will need two Kubernetes clusters where you want to deploy k8gb and enable global load balancing between them.

You can reuse local clusters from the Infoblox tutorial, the EKS-based setup from Route53 tutorial or any Kubernetes deployment method that is convenient to you.

The specific Kubernetes deployment method is not essential for the focus of this documentation guide.

For simplicity, we will assume that clusters have simple 'eu' and 'us' geotags.

Deploy k8gb with Cloudflare integration enabled

Use helm to deploy a stable release from the Helm repo.

helm repo add k8gb https://www.k8gb.io

Example values.yaml configuration files can be found here

Remember to change the zone-related values to point configuration to your own DNS zone.

k8gb:
  dnsZone: "cloudflare-test.k8gb.io"
  # -- main zone which would contain gslb zone to delegate
  edgeDNSZone: "k8gb.io" # main zone which would contain gslb zone to delegate

Cloudflare-specific configuration

Let's look closer at the Cloudflare section of the configuration examples.

cloudflare:
  # -- Enable Cloudflare provider
  enabled: true
  # -- Cloudflare Zone ID
  zoneID: cdebf92e613133e4bb176a14a9c5b730
  # -- Configure how many DNS records to fetch per request
  # see https://github.com/kubernetes-sigs/external-dns/blob/master/docs/tutorials/cloudflare.md#throttling
  dnsRecordsPerPage: 5000

Follow https://developers.cloudflare.com/fundamentals/setup/find-account-and-zone-ids/ to find your zoneID

Install the k8gb helm chart in each cluster

In eu cluster, execute

helm -n k8gb upgrade -i k8gb k8gb/k8gb --create-namespace -f ./docs/examples/cloudflare/k8gb-cluster-cloudflare-eu.yaml

In us cluster, execute

helm -n k8gb upgrade -i k8gb k8gb/k8gb --create-namespace -f ./docs/examples/cloudflare/k8gb-cluster-cloudflare-us.yaml

Create a Cloudflare secret in each cluster

kubectl -n k8gb create secret generic cloudflare --from-literal=token=<api-secret>

Note: you can create Cloudflare API tokens at https://dash.cloudflare.com/profile/api-tokens

Create test Gslb resource

Now we can test the setup with a pretty standard Gslb resource configuration.

apiVersion: k8gb.absa.oss/v1beta1
kind: Gslb
metadata:
  name: test-gslb-failover
  namespace: test-gslb
spec:
  ingress:
    ingressClassName: nginx
    rules:
    - host: failover.cloudflare-test.k8gb.io
      http:
        paths:
        - backend:
            service:
              name: frontend-podinfo
              port:
                name: http
          path: /
          pathType: Prefix
  strategy:
    dnsTtlSeconds: 60 # Minimum for non-Enterprise Cloudflare https://developers.cloudflare.com/dns/manage-dns-records/reference/ttl/
    primaryGeoTag: eu
    splitBrainThresholdSeconds: 300
    type: failover

The only unusual thing here is spec.strategy.dnsTtlSeconds that should be of a minimum 60-second value in case you are operating a non-Enterprise Cloudflare subscription. The lower values will be rejected by Cloudflare API.

Apply Gslb resource to each cluster.

kubectl apply -f ./docs/examples/cloudflare/test-gslb-failover.yaml

Check Zone Delegation configuration

As a result of the setup, you should observe DNSEndpoint automatically created, similar to the one below:

$ kubectl -n k8gb get dnsendpoints.externaldns.k8s.io k8gb-ns-extdns -o yaml
apiVersion: externaldns.k8s.io/v1alpha1
kind: DNSEndpoint
metadata:
  annotations:
    k8gb.absa.oss/dnstype: extdns
  creationTimestamp: "2023-11-12T19:55:20Z"
  generation: 3
  name: k8gb-ns-extdns
  namespace: k8gb
  resourceVersion: "5851"
  uid: 5d240eb8-1c19-48c3-bf69-508545f52ea4
spec:
  endpoints:
  - dnsName: cloudflare-test.k8gb.io
    recordTTL: 60
    recordType: NS
    targets:
    - gslb-ns-eu-cloudflare-test.k8gb.io
    - gslb-ns-us-cloudflare-test.k8gb.io
  - dnsName: gslb-ns-us-cloudflare-test.k8gb.io
    recordTTL: 60
    recordType: A
    targets:
    - 172.26.0.8
    - 172.26.0.9

On the Cloudflare dashboard side, you should observe that NS and glue A records are automatically created:

Troubleshooting

If something is not working as expected with the integration, check the logs of the externalDNS pod that is responsible for the creation of the DNS records with Cloudflare API.

kubectl -n k8gb logs -f deploy/external-dns