Netcup DynDNS API Job using Ansible

Summary

This container uses cron and ansible to periodically set dns entries for the current device.

This is meant to be a (mostly) drop-in replacement for b2un0/docker-netcup-dyndns You should just need to change the value for MODE from both to @ *.

This in itself does the same as the original but come with the folling improvements:

• fallback identity server when the original is down
• creates the domain entries automatically
• can set other subdomains than just @ and *

Setup

Docker

version: '2'
services:
    netcup-dyndns:
        container_name: netcup-dyndns
        environment:
            SCHEDULE: "*/10 * * * *"
            DOMAIN: "example.com"
            MODE: "@ *"
            IPv4: "yes"
            IPv6: "yes"
            CUSTOMER_ID: ${CUSTOMER_ID}
            API_KEY: ${API_KEY}
            API_PASSWORD: ${API_PASSWORD}
            TZ: "Europe/Berlin"
        restart: unless-stopped
        image: ghcr.io/lightlike/netcup-dyndns:latest

Without Docker

This container only executes the ansible playbook as a cronjob. Any dependencies can be found inside the Dockerfile so this can be executed without the container.

This is not supported and you have to know how to work with ansible.

Variables

Variable	Function
SCHEDULE	Cron schedule for executing ansible playbook default: every 10 minutes time between executions can be reduced but try not to reduce it to much.
DOMAIN	The domain the values should be set to
MODE	Subdomains the IPs should be set to (separated by space) default: @ and *
IPv4	if IPv4 should be set default: no
IPv6	if IPv6 should be set default: no
CUSTOMER_ID	netcup customer id
API_KEY	netcup API key
API_PASSWORD	netcup API password

Funtionality

This container uses http://ident.me/ and http://tnedi.me/ to get the current IP of the Server and sets that as in netcup. The Documentation for these sites can be found under: https://api.ident.me/ and https://api.tnedi.me/ These Websites are located in Germany if that may couse trouble for you.

IPv6

Docker by default does not support outgoing requests using IPv6. This can be enabled by following this guide: https://docs.docker.com/config/daemon/ipv6/ If you do not need IPv6 for anything else, you can also just set:

version: '2'
services:
    netcup-dyndns:
        container_name: netcup-dyndns
        network_mode: "host"
        environment:
            ...
        restart: unless-stopped
        image: ghcr.io/lightlike/netcup-dyndns:latest

That should not cause any problems as this container does not expose any ports.

Replacing the current logic

The current ansible logic can be replaced by replacing the update-dns.yaml. This can be done by mounting a new file from the host system to the container.

version: '2'
services:
    netcup-dyndns:
        container_name: netcup-dyndns
        environment:
            ...
        volumes:
            - /path/to/new/yaml:/netcup-dns/ansible/update-dns.yaml:ro
        restart: unless-stopped
        image: ghcr.io/lightlike/netcup-dyndns:latest