Here are the only commands used to install ZFS on Centos 7
First install from CentOS-7-x86_64-Minimal-1611.iso
yum -y install epel-release yum -y update reboot
yum localinstall --nogpgcheck http://download.zfsonlinux.org/epel/zfs-release.el7.noarch.rpm # backup kept here: https://s3-us-west-2.amazonaws.com/fishdust/zfs-release.el7.noarch.rpm yum -y install kernel-devel yum -y install zfs modprobe zfs
modprobe zfs, ZFS did not run.
After reboot, ZFS was not running either.
I followed the instructions here, specifically:
systemctl preset zfs-import-cache zfs-import-scan zfs-mount zfs-share zfs-zed zfs.target reboot
systemctl enable zfs-import-scan
reboot again, and all works.