With the EOL of gluster 6, it would be nice the oVirt 4.3 branch keeps up to date with the latest gluster version's, where 8 is just released, but 7 still being maintained. It would be nice the yum dependency repository of oVirt would be updated to reflect this. the 6 could just be changed to an 7 in the file, like; [ovirt-4.3-centos-gluster7] name=CentOS-$releasever - Gluster 7 baseurl=http://mirror.centos.org/centos/7/storage/$basearch/gluster-7/ gpgcheck=1 enabled=1 gpgkey=https://www.centos.org/keys/RPM-GPG-KEY-CentOS-SIG-Storage
Gluster 7 is enabled by default in oVirt 4.4. Since no further development is going to happen in 4.3, also no further testing is done there. Please upgrade to oVirt 4.4 for getting newer Gluster as well included in oVirt Node. As an alternative, on CentOS 7 systems you can "yum install centos-release-gluster7" but please be aware this has not been tested for oVirt 4.3 compatibility.