I've ended up resetting engine's MTU and reverting the MTU on ovirtmgmt to 1500 and resyncing all the host nodes.
The underlying NIC MTU was still 9000 for other VLANs.
Afterwards, the host is available again and was able to install with engine deploy enabled.

Maybe the network switch|router is misconfigured?
I don't have the direct access to examine it.
The symptom was that ssh host to engine, or the other way, would connect but hang before completing negotiations.
This caused the "unresponsive" host problems.

On Wed, Jan 30, 2019 at 5:02 AM Sahina Bose <sabose@redhat.com> wrote:
On Tue, Jan 29, 2019 at 10:05 PM Edward Berger <edwberger@gmail.com> wrote:
>
> Done. It still won't let me remove the host.
> clicked maintenance, checked ignore gluster... box.
> clicked remove.  got popup " track00.yard.psc.edu:
>
> Cannot remove Host. Server having Gluster volume."

If the server has bricks, the only option to remove the host is to
replace/remove the bricks.
Can you try reinstall of host instead?

>
>
> On Tue, Jan 29, 2019 at 4:24 AM Sahina Bose <sabose@redhat.com> wrote:
>>
>> On Mon, Jan 28, 2019 at 7:31 AM Edward Berger <edwberger@gmail.com> wrote:
>> >
>> > I have a problem host which also is the one I deployed a hyperconverged oVirt node-ng cluster from with the cockpit's hyperconverged installation wizard.
>> >
>> > When I realized after deploying that I hadn't set the MTUs correctly for the engine-mgmt, associated vlan and eno.2 device and also for my infiniband interface ib0, I went in and tried to set them to new values 9000 and 65520 it got into some kind of hung state.
>> >
>> > The engine task window shows a task in "executing" and a never ending spinning widget
>> > "Handing non responsive Host track00..."
>> >
>> > I can tried updating the hosts /etc/sysconfig/network-scripts by hand.
>> > I've tried every combination of the engines set host in maintenance mode , "sync networks" "refresh host capabilities" activating and rebooting, but I'm still stuck with an unresponsive host.
>> >
>> > I had another host that also failed but it allowed me to put it into maintenance mode and then remove it from the cluster and "add new" it back and it was happy.
>> >
>> > This one won't let me remove it because its serving the gluster volume mount point, even though I did give the mount options for the 2nd and 3rd backup volume servers.
>> >
>> > I'd appreciate any help restoring it to proper working order.
>>
>> Can you try removing the host after checking the "Ignore quorum loss ..." box?
>>
>> >
>> > I'm attaching the gzip'd engine log.
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