Dynamic DNS with IP objects
As described in the core concept, IP objects allow you to use cloudflare-operator as a dynamic DNS controller.
In this guide, we will configure an IP object to fetch the public IP address from the internet and use it as the target content for a DNS record.
Simple example
Create an IP object with the following content:
---
apiVersion: cloudflare-operator.io/v1
kind: IP
metadata:
name: external-v4
spec:
ipSources:
- requestMethod: GET
url: https://ifconfig.me/ip
- requestMethod: GET
url: https://ipecho.net/plain
- requestMethod: GET
url: https://myip.is/ip/
- requestMethod: GET
url: https://checkip.amazonaws.com
- requestMethod: GET
url: https://api.ipify.org
type: dynamic
interval: 5m0s
The IP object will fetch the public IP address from the internet using one of the specified URLs.
If the request fails, the next URL will be tried. If all URLs fail, the last known IP will be used and
the ready condition will be set to false.
Now, create a DNS record object with the following content:
---
apiVersion: cloudflare-operator.io/v1
kind: DNSRecord
metadata:
name: example-com
namespace: cloudflare-operator
spec:
name: example.com
ipRef:
name: external-v4 # reference to the IP object
proxied: true
ttl: 1
type: A
Response filtering
Using jq
You can use jq to filter the response content.
Here is an example for ipify.org:
Request content:
$ curl 'https://api.ipify.org?format=json'
{"ip":"69.42.0.69"}
The IP object would look like this:
---
apiVersion: cloudflare-operator.io/v1
kind: IP
metadata:
name: external-v4
spec:
ipSources:
- requestMethod: GET
url: https://api.ipify.org?format=json
responseJQFilter: .ip
type: dynamic
interval: 5m0s
Using regex
If you want to use a regex, you can use the postProcessingRegex field.
This might be useful if you want to extract the IP address from a HTML page.
The regex must contain a single capture group.
Here is an example for ifconfig.me:
Request content:
$ curl 'https://ifconfig.me/'
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
...
In this case, the IP object would look like this:
---
apiVersion: cloudflare-operator.io/v1
kind: IP
metadata:
name: external-v4
spec:
ipSources:
- requestMethod: GET
url: https://ifconfig.me/
postProcessingRegex: '(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})'
type: dynamic
interval: 5m0s
Fetching IP from an API
If you want to fetch the IP address from an API, you can use the responseJQFilter field.
In this example, we are going to fetch the IP from a Hetzner cloud instance.
To authenticate with the API, you can configure the IP object to use a secret
where the secret key will be used as the header name
and the secret value will be used as the header value.
Create a secret with the following content:
---
apiVersion: v1
kind: Secret
metadata:
name: hetzner-cloud-api-key
namespace: cloudflare-operator
stringData:
Authorization: Bearer <your-api-token>
Now, create an IP object with the following content:
---
apiVersion: cloudflare-operator.io/v1
kind: IP
metadata:
name: my-instance-v4
spec:
ipSources:
- requestHeaders:
Accept: application/json
requestHeadersSecretRef:
name: hetzner-cloud-api-key
namespace: cloudflare-operator
requestMethod: GET
responseJQFilter: .servers[] | select(.name == "my-instance.example.com").public_net.ipv4.ip
url: https://api.hetzner.cloud/v1/servers
type: dynamic
interval: 5m0s