ddclient

https://help.ubuntu.com/community/DynamicDNS#Redirecting_a_registered_hostname_to_a_dynamic_DNS_name

# Configuration file for ddclient generated by debconf
# /etc/ddclient.conf

daemon=300

pid=/var/run/ddclient.pid

ssl=yes

protocol=googledomains

use=web, web=https://domains.google.com/nic/update, web-skip='IP Address'

server=domains.google.com

login="auto generated"# login name from domains.google.com

password="auto generated" #password from domains.google.com

example.com