you have to shutdown all the hosts in the cluster and when you update the cluster I think you have to run reinstall from the install menu so installs the gluster packages. I tried a short-cut with ours and as one host was in maintenance it reinstalled and activated it so there was somewhere for the VMs and SPM to migrate to.

From: Maton, Brett <matonb@ltresources.co.uk>
Sent: 27 September 2018 14:27
To: Ovirt Users
Subject: [ovirt-users] Enabling Gluster Service

I just enabled the Gluster service in an existing oVirt 7.2.7-1 cluster via the Web-UI which put all hosts into non-operational status.

Lots of events being created:

Could not find gluster uuid of server host001.local on Cluster testlab.

Could not find gluster uuid of server host002.local on Cluster testlab.

Could not find gluster uuid of server host003.local on Cluster testlab.

and a bunch of failed vm migrations

Is it possible to add glusterfs after ovirt has been installed and configured?