In case there's already a DHCP config for netplan for the private IP address:
File: /etc/netplan/50-cloud-init.yaml
Contents:
# This file is generated from information provided by
# the datasource. Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following: