Comment 15 for bug 1845303

We have identified an unexpected consequence of the patches landed in this bug which is that /etc/resolve.conf will likely contain more than one search domain, one from the host network dhcp (e.g. maas) and one from the o-hm0 port dhcp (ml2-dns). The issue is that if the openstack dns search domain is written first, dns requests timeout before trying the maas one which is needed to resolve the hostname on o-hm0 and this caused neutron to fail to configure networking (ovs) on that unit. There is a really simple fix for this which is to add UseDomains=route to the networkd config written by the charm. We have tested this in production and are confident it fixes the problem so I will submit as a patch.