Cloud-init Reference
Ubuntu accept-ra: false
This will set accept-ra to false on all Ubuntu templates using the ens3 interface naming.
write_files:
    -
        encoding: b64
        content: bmV0d29yazoKICB2ZXJzaW9uOiAyCiAgZXRoZXJuZXRzOgogICAgZW5zMzoKICAgICAgYWNjZXB0LXJhOiBmYWxzZQ==
        owner: 'root:root'
        path: /etc/netplan/99-user-conf.yaml
        permissions: '0600'