It turns out we do need to set DNS on the overcloud subnet. It should be the .2 of the CIDR under test and not the _admin_net's .2. There seems there are security group rules in the way.
It turns out we do need to set DNS on the overcloud subnet. It should be the .2 of the CIDR under test and not the _admin_net's .2. There seems there are security group rules in the way.