It seems to be failing on adding the ovirtmgmt bridge to the interface defined on the host as part of the
host addition installation process. I had this issue during a hosted-engine install when ovirtmgmt was on a tagged
port which was already configured with a chosen name not supported by the ovirt installation scripts.
After I reconfigured the network config with the correct style name, I was able to install hosted engine on CentOS8.
Check if ovirtmgmt exists on the host you're trying to add to your ovirt installation, note which interface should
have that network bridge added.
In my case, the network port needed to be configured in the form of eno1.## where ## was the vlan number, replace en01 with correct ethernet interface.
Similar issues could happen if you're using a bond named something other than what the installation scripts expect (bond.#).
Its a little confusing, but there are actually two different places to 'edit' a host's config from engine.
The obvious one is 'edit host' but the feature to set networks per device or configure host devices for passthrough
is under the other (almost hidden) area of the engine web UI.
Under the engine UI, try to set the non-op host into 'maintenance' and then click on the hostname in compute:hosts page, and then networks tab
and then 'setup host networks' and to try to add it by dragging it from the right hand side of the page to the correct interface on the left
and saving it. If you're defining any other logical networks you'll need to get to that page per host to set them up.