Comment 24 for bug 1713803

It looks like open-iscsi makes use of resolvconf in debian/net-interface-handler, but does check for its presence before doing so. That said, there is not additional integration with anything to set nameservers/search domains, so open-iscsi will need further investigation to see if all is well with it when resolvconf is not present and the iSCSI server is configured with an FQDN rather than a straight IP address.