I'm running into the exact same issue as described in this thread. The HostedEngine VM (HE) loses connectivity during the deployment while on the NAT'd network and the deployment fails. My HE VM is never migrated to shared storage because that part of the process hasn't been reached, nor have I been asked for the shared storage details, which are simple NFS shares. I've tried the deployment from the CLI and through Cockpit, both times using the Ansible deployment, and both times reaching the same conclusion.
I did manage to connect to the Centos 7 host that is running the HE guest with virt-manager and moved the NIC to the 'ovirtmgmt' vswitch using macvtap, which allowed me to access HE from the outside world. One of the big issues though is that the HE isn't on shared storage and I'm not sure how to move it there. I'm running 2 Centos 7 hosts with different CPU makes, AMD and Intel. So i have two separate single-host clusters but I'm trying to at least have the HA setup for the HE, which I think is still possible. I know that I won't be able to do a live migration, but that's not a big deal. I'm afraid my failed deployment of HE is preventing this and I'm at an impasse. I don't want to give up on oVirt but it's becoming difficult to get my lab environment operational and I'm wasting a lot of time troubleshooting.
Any help or suggestions would be greatly appreciated.