There is a lot of other dependencies to declare other than postfix, MTA would have been better.
I agree, and suggest to open an RFE on ovirt-host (and elsewhere? didn't check) to change the Requires:.
ovirt-host have a lot of dependencies: rpm -q --requires ovirt-host NetworkManager-config-server cockpit cockpit-dashboard cockpit-machines-ovirt cockpit-networkmanager cockpit-ovirt-dashboard dracut-fips firewalld glusterfs-rdma ipa-client katello-agent mailx net-snmp net-snmp-utils ovirt-host-dependencies = 4.2.3-1.el7 ovirt-hosted-engine-setup ovirt-provider-ovn-driver postfix python-firewall rng-tools rpmlib(CompressedFileNames) <= 3.0.4-1 rpmlib(FileDigests) <= 4.6.0-1 rpmlib(PayloadFilesHavePrefix) <= 4.0-1 screen sysstat tcpdump vdsm-hook-ethtool-options vdsm-hook-fcoe vdsm-hook-openstacknet vdsm-hook-vfio-mdev vdsm-hook-vhostmd vdsm-hook-vmfex-dev Many of thee are useless depending of your setup. rng-tools, for example, but my hardware don't provides any of the needed random generators. screen, tcpdump ? I'm quite surprised. glusterfs-rdma, I'm not doing glusterfs, and I don't have any hardware to do rdma