Kubernetes Cloudflare Sync

This App is intended to run in your Kubernetes Cluster and sync DNS records on Cloudflare with your nodes' IPs.

Example Usage

You can read this article to get an idea on why you would want to use it: http://www.doxsey.net/blog/kubernetes--the-surprisingly-affordable-platform-for-personal-projects

Build

GKE provides you with a private cotainer image repository for each cluster. The following two commands build the app and publish into your cluster-specific repository.

docker build -t gcr.io/PROJECT_ID/kubernetes-cloudflare-sync:latest . docker push gcr.io/PROJECT_ID/kubernetes-cloudflare-sync:latest

Configure

apiVersion: apps/v1
kind: Deployment
metadata:
  name: kubernetes-cloudflare-sync
  labels:
    app: kubernetes-cloudflare-sync
spec:
  replicas: 1
  selector:
    matchLabels:
      app: kubernetes-cloudflare-sync
  template:
    metadata:
      labels:
        app: kubernetes-cloudflare-sync
    spec:
      serviceAccountName: kubernetes-cloudflare-sync
      containers:
      - name: kubernetes-cloudflare-sync
        image: gcr.io/PROJECT_ID/kubernetes-cloudflare-sync
        args:
        - --dns-name=kubernetes.example.com
        env:
        - name: CF_API_KEY
          valueFrom:
            secretKeyRef:
              name: cloudflare
              key: api-key
        - name: CF_API_EMAIL
          valueFrom:
            secretKeyRef:
              name: cloudflare
              key: email

Important: Make sure to replace PROJECT_ID

The app needs two types of permissions:

1. talk to cloudflare and update DNS
2. get a list of nodes in the cluster and read their IP

The former requires just the API keys from cloudflare. We can store them as secret in the cluster by running:

kubectl create secret generic cloudflare --from-literal=email=YOUR_CLOUDFLARE_ACCOUNT_EMAIL_ADDRESS_HERE --from-literal=api-key=YOUR_CLOUDFLARE_GLOBAL_API_KEY_HERE

For the latter we create a clusterrolebinding in our cluster by running:

kubectl create clusterrolebinding cluster-admin-binding --clusterrole cluster-admin --user YOUR_EMAIL_ADDRESS_HERE

Important: Make sure this is the same E-Mail as you use for running kubectl.

apiVersion: v1
kind: ServiceAccount
metadata:
  name: kubernetes-cloudflare-sync
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: kubernetes-cloudflare-sync
rules:
- apiGroups: [""]
  resources: ["nodes"]
  verbs: ["list", "watch"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: kubernetes-cloudflare-sync-viewer
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: kubernetes-cloudflare-sync
subjects:
- kind: ServiceAccount
  name: kubernetes-cloudflare-sync
  namespace: default

Applying all configs by running:

kubectl apply -f .

ENV

• CF_API_EMAIL The email address to use for cloudflare
• CF_API_KEY The key to use for cloudflare
• CF_API_TOKEN The token to use for cloudflare (in lieu of email and key)
• CF_PROXY Enable cloudflare proxy on dns (default false)
• CF_TTL TTL for dns (default 120)
• DNS_NAME The dns name for the nodes, comma-separated for multiple (same root)
• USE_INTERNAL_IP Use internal ips too if external ip's are not available
• SKIP_EXTERNAL_IP Don't sync external IPs (use in conjunction with --use-internal-ip)
• NODE_SELECTOR Node selector query