Well, actually I want to migrate both DNS hostnames and the subnet (from a /24 to a /16) to which the ovirtmgr interface is connected.
The second change is the most problematic as you say..in any case what would be the best procedure, even if it implies downtime?

2016-10-06 10:04 GMT+02:00 Barak Korren <bkorren@redhat.com>:
> Is there a clean way and possibly without downtime to change the hostname
> and IP addresses of all the hosts in a running oVirt cluster?

As long as you don't change the VLANs and subnets for the hosts, you
can change IPs by putting the hosts into maintenance one-by-one (so
that VMs migrate to other hosts), removing them and re-adding with the
new IPs.

Hostnames (Except the engine's) should not matter for oVirt at all
(you can register hosts to oVirt with names, but I wouldn't recommend
that for production, as the DNS becomes a massive SPOF).

If you change the subnet the hosts are attached to, and you have VMs
that are using that subnet as well, you will not be able to do this
without downtime, because the VMs will probably not have the right IP
settings to allow them to communicate using the new subnet...

--
Barak Korren
bkorren@redhat.com
RHEV-CI Team



--
Davide Ferrari
Senior Systems Engineer