certbot is a cli that enable you to get a free ssl cert for your site.
Once you install the cli, it's one step to get a cert chain. Be aware that juju.one is not the same as *.juju.one domain. To get one cert for all your domain, you have to pass two domain parameters -d juju.one -d *.juju.one
Here's the command to get cert for my isp and domain.
certbot certonly --dns-linode --dns-linode-credentials linode.ini -d juju.one -d *.juju.one