This small Alpine Linux based Docker image will allow you to use the free CloudFlare DNS Service as a Dynamic DNS Provider (DDNS).

Image Tag	Architecture	OS	Size
latest	x64	Alpine Linux
armhf	arm32v6	Alpine Linux
aarch64	arm64	Alpine Linux

Quick Setup:

docker run \
  -e API_TOKEN=xxxxxxx \
  -e ZONE=example.com \
  -e ZONE_ID=xxxxxxx \
  -e SUBDOMAIN=subdomain \
  oznu/cloudflare-ddns

This image will also run on a Raspberry Pi or other ARM based boards that support Docker using the armhf or aarch64 tags:

docker run \
  -e API_TOKEN=xxxxxxx \
  -e ZONE=example.com \
  -e ZONE_ID=xxxxxxx \
  -e SUBDOMAIN=subdomain \
  oznu/cloudflare-ddns:armhf

• --restart=always - ensure the container restarts automatically after host reboot.
• -e API_TOKEN - Your CloudFlare API Token. Get it here: https://dash.cloudflare.com/profile/api-tokens. Required
• -e ZONE - The DNS zone that DDNS updates should be applied to. Required
• -e ZONE_ID - The DNS zone ID that matches the provided ZONE. Required
• -e SUBDOMAIN - A subdomain of the ZONE to write DNS changes to. If this is not supplied the root zone will be used.
• -e PROXIED - Set to true to make traffic go through the CloudFlare CDN. Defaults to false.
• -e RRTYPE=A - Set to AAAA to use set IPv6 records instead of IPv4 records. Defaults to A for IPv4 records.
• -e DELETE_ON_STOP - Set to true to have the dns record deleted when the container is stopped. Defaults to false.

If you need multiple records pointing to your public IP address you can create CNAME records in CloudFlare.

If you're wanting to set IPv6 records set the envrionment variable RRTYPE=AAAA. You will also need to run docker with IPv6 support, or run the container with host networking enabled.

If you prefer to use Docker Compose:

version: '2'
services:
  cloudflare-ddns:
    image: oznu/cloudflare-ddns:latest # change 'latest' to 'armhf' or 'aarch64' if running on an arm device
    restart: always
    environment:
      - API_TOKEN=xxxxxxx
      - ZONE=example.com
      - ZONE_ID=xxxxxxx
      - SUBDOMAIN=subdomain
      - PROXIED=false