Comment 6 for bug 1876029

You can use ingress-address which replaced private-address - it is populated by Juju when a unit enters the relation scope at the Juju level - in other words, on <name>-relation-joined an ingress-address for a remote unit will be present.

`network-get <binding-name>` can be used to retrieve ingress-address and bind-address of the unit for the current hook execution.

As for hostnames, see https://bugs.launchpad.net/juju/+bug/1864086 for more info.