Install nightly snapshot

From master branches

You just need to execute:

yum install http://resources.ovirt.org/pub/yum-repo/ovirt-release-master.rpm

for adding all needed repositories.

From 4.2 branches

You need to install both stable release rpm and development release rpm:

yum install http://resources.ovirt.org/pub/yum-repo/ovirt-release42.rpm

yum install http://resources.ovirt.org/pub/yum-repo/ovirt-release42-snapshot.rpm

for adding all needed repositories.