ovh-dynhosts

Docker image to update OVH dynhosts regularly. Based on Alpine linux.

Small domain lists

Large domain lists

Why

A DynHost is used to assign a dynamic ip to a subdomain. This can be very useful to make your local development machine available via a public subdomain.

Configure OVH

In your OVH domain settings head over to the DynHost tab and follow the steps to create your dynhost.

Small domain lists

Run container

The image is available via Docker Hub.

docker run \
  -e DDNS=domain.example.com,subdomain.example.com,otherdomain.com \
  -e LOGIN=login \
  -e PASSWORD=password \
  --restart always \
  --name ovh-dynhosts \
  paulobergine/ovh-dynhosts

Or via docker-compose:

version: '3'

services:
  ovh-dynhosts:
    image: paulobergine/ovh-dynhosts:latest
    container_name: ovh-dynhosts
    restart: unless-stopped
    environment:
      DDNS: domain.example.com,subdomain.example.com,otherdomain.com
      LOGIN: login
      PASSWORD: password

Of course you need to insert your credentials.

This will update the dynhost every 15 minutes if the ip changed.

Large domain lists

If you need to update a large list of domains, you can use a JSON file instead of an environment variable.

Use this Dockerfile :

FROM alpine:3.9

RUN apk add --update --no-cache curl bind-tools jq dos2unix

WORKDIR /usr/src/app

COPY dynhost.sh .
COPY DDNS.json .

RUN chmod +x ./dynhost.sh

RUN dos2unix -b ./dynhost.sh

RUN ln -sf /usr/src/app/dynhost.sh /etc/periodic/15min/dynhost

CMD ["crond", "-f"]

Or via docker-compose:

version: '3'

services:
  ovh-dynhosts:
    container_name: ovh-dynhosts
    restart: unless-stopped
    build:
      dockerfile: Dockerfile
      context: .
      args:
        LOGIN: "login"
        PASSWORD: "password"

For this to work you will need to create and add to the folder a JSON file like this example :

{
    "DDN": "domain.example.com"
}
{
    "DDN": "subdomain.example.com"
}
{
    "DDN": "otherdomain.com."
}

Then add the new script :

#!/bin/sh

echo "Starting script"

DDNS=`cat /usr/src/app/DDNS.json | jq '.DDN'`

for DDN in $DDNS
do
  echo "Checking IP" >> /usr/src/app/dynhost.log

  IP=$(dig -4 TXT +short o-o.myaddr.l.google.com @ns1.google.com | tr -d \")
  CURRENT_IP=$(dig +short $DDN)

  if [ "$IP" ]; then
    if [ "$CURRENT_IP" != "$IP" ]; then
        echo "Updating $DDN from $CURRENT_IP to $IP" >> dynhost.log
        curl --user "${LOGIN}:${PASSWORD}" "http://www.ovh.com/nic/update?system=dyndns&hostname=${DDN}&myip=${IP}" >> dynhost.log 2>&1
    else
        echo "No update required" >> dynhost.log
    fi
  else
    echo "IP not found" >> dynhost.log
  fi
done